Review and synthesis of bioenergy and biofuels ...

Review and synthesis of bioenergy and biofuels research

Report for Defra Ricardo-AEA/R/ED59367 Issue FINAL Date 13/06/2014


Customer:

Contact:

Defra

Kathryn Rushton Ricardo-AEA Ltd Gemini Building, Harwell, Didcot, OX11 0QR t: 01235 75 3109 e: [email protected] Ricardo-AEA is certificated to ISO9001 and ISO14001

Customer reference: SCF0401 Confidentiality, copyright & reproduction: This report is the Copyright of Defra and has been prepared by Ricardo-AEA Ltd under contract to Defra dated 13/01/2014. The contents of this report may not be reproduced in whole or in part, nor passed to any organisation or person without the specific prior written permission of Defra. Ricardo-AEA Ltd accepts no liability whatsoever to any third party for any loss or damage arising from any interpretation or use of the information contained in this report, or reliance on any views expressed therein.

Authors: Kathryn Rushton, Richard J Smithers, Susan O’Brien, Aaron Burton, J Webb, Peter Alexander, Judith Bates, Robert Stewart, Pat Howes Approved By: Kathryn Rushton Date: 13 June 2014 Ricardo-AEA reference: Ref: ED59367- Issue FINAL

Ref: Ricardo-AEA/R/ED59367/Issue FINAL

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Acknowledgements We would like to thank the following people for contributing to this project: Luke Spadavecchia (Defra), Keeley Bignal (DfT) and Ruhi Babbar (DECC) for their role in the Project Steering Group. Duncan Eggar (BBSRC), Geraldine Newton-Cross (ETI), Andrew Lovett (University of East Anglia (UEA)), Michelle Truman (NERC), David Turley (NNFCC), Peter Alexander (SRUC), Clare Wenner (UK Renewable Energy Association (REA)), Patricia Thornley (Tyndall Centre), Gail Taylor (Southampton University), Astley Hastings (Aberdeen University), Niall McNamarra (CEH Lancaster Environment Centre), Jonathan Oxley, Harley Stoddart (HGCA), Angela Karp (Rothamsted) and Iain Donnison (IBERS) for providing information for the project.


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Executive summary This report presents the results of a Rapid Evidence Assessment into the issues surrounding the production of feedstocks (both imported and home-grown) currently used in the UK for bioenergy, excluding those associated with forestry and wood, and anaerobic digestion. Issues relating to conversion were also not addressed. The aim of the project was to provide a common evidence base for use by Defra and other government departments. In addition to considering peer-reviewed and grey literature, we discussed relevant ongoing research in the UK with some of the key researchers. The results are presented in theme summaries, which comprise the main chapters of this report, and are supported by evidence-base spreadsheets, which are included as appendices to the report. The purpose of each theme chapter is to provide a high-level summary of the topic, including:       

Current issues Information in the literature Confidence in the information reviewed Trends Evidence gaps Current research Suggestions for further research.

The evidence-base spreadsheets list the key references selected for use in this review and for each document provide details of:        

The reliability of data sources The strength of data Data quality Relevance to the theme Relevance to specific feedstocks Objectives Key messages Relevance to other themes.

After identifying suggestions for further research in relation to individual themes, it became apparent that there were some evidence gaps identified across more than one theme. These are:     

Impacts on marginal soils in terms of biodiversity, yields and economic performance, water use and water quality Integrated assessment of optimal land use, e.g. in terms of food, fuel, water availability, biodiversity and social issues, as well as bioenergy The use of bioenergy crops in integrated farming Landscape- or catchment-scale assessment Up-to-date guidelines for growers on bioenergy crops and their impacts on water quantity, water quality and biodiversity.

It should be noted that there is a considerable amount of relevant ongoing research in the UK and new research is also being commissioned, therefore, gaps identified may be the subject of research projects in the near future.


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The following table lists the themes covered by the project and highlights key findings. Theme

Key findings

Current state of the market

 



UK agricultural production impacts



 

 Socio-economics

  



GHG mitigation potential 



The UK Biomass strategy foresees a significant contribution to UK energy production from bioenergy up to 2050; perhaps up to 350,000ha of energy crops by 2020 and 800,000ha of energy crops by 2050. The current UK target for renewable transport biofuels is 4.75% by volume of liquid road transport fuels by 2014, which may rise to 10% by 2020. No advanced biofuels made from lignocellulosic biomass are currently produced in the UK although this may change in the future. Currently bioenergy for heat and power is mainly produced from imported solid biomass. There is a robust but limited supply of UK wastes and straw currently used for heat and power production. The current supply of short rotation coppice (SRC) and the energy grass, Miscanthus, is very low, with about 10,000ha planted in the UK. Modelling suggests that most arable land in the UK, up to 8.5Mha, is suitable for energy-crop production. The availability of this land depends on a range of assumptions. Estimates of suitable and available land, which take into account food production and sustainability constraints, range from 0.57Mha to 1.64Mha. In the UK, research into perennial crops has focused on SRC willow and poplar and Miscanthus and continues to address potential to increase their yield and energy content. There is currently no evidence of particular varieties of energy crops being required by end users. However, long-term breeding research is evaluating traits that would make perennial crops more suitable for processing as biofuels. There is very limited evidence on the potential for integrated food and energy-crop production in the UK. Both UK-produced crops and imported crops will have socio-economic impacts. For imported crops the main issues are land-use rights, working conditions and food security in the producer country. For UK crops, potential benefits are rural development and job creation, with recent estimates of 35-50,000 jobs supported in the UK bioenergy sector, excluding biofuels, to meet the bioenergy projections in DECC’s Renewable Roadmap (25-41 TWh of electricity and 33-44 TWh of heat). These jobs are primarily in plant construction (47%) and operation (33%), while UK feedstock production only accounts for 14% of job creation. This does not take into account any displacement of jobs from previous agricultural activities. A range of barriers to adoption of bioenergy have been identified, including public perception and farmer attitudes to energy crops. These need to be addressed to achieve substantial uptake and thus generate anticipated benefits. When biomass is burnt it releases the same amount of carbon dioxide into the atmosphere as was removed during plant growth. However, bioenergy crops are not carbon neutral, as there are emissions from fossil fuels used in their planting, fertilisation, harvesting, processing and transportation. In addition it is also necessary to account for the benefits of any co-products (e.g. rape meal) produced when processing, emissions from land-use change (LUC; both direct and indirect) and changes in carbon sequestration. The UK must comply with the Renewable Energy Directive (RED), which sets minimum greenhouse-gas (GHG) savings that biofuels must meet and sets out a calculation methodology that must be applied. The minimum GHG-emission saving compared to fossil fuels is currently 35%, rising to 50% from 2017, and from 2018 it must be 60% for new


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Theme

Land-use change

Key findings







Biodiversity



 



Water use

   

Water quality





installations. In the UK, the methodology has been incorporated into the DfT's Carbon Calculator for biofuels and bioliquids. Ofgem has a similar carbon calculator for biomass used for heat and power production, which is also based on the methodology set out in the RED. All bioenergy crops can cause land-use change (LUC), either directly by being grown on previously uncultivated land, or indirectly by displacing food/ feed crops from agricultural land, leading to additional land being brought into cultivation elsewhere. Straw, chicken litter, tallow and wastes are assumed to be feedstocks that do not cause land-use change. European bioenergy sustainability legislation currently includes provision for direct land-use change, and the UK is involved in negotiations at the EU level to find a policy solution which mitigates the impact of indirect land-use change (ILUC). It is likely that a combination of approaches will be the most effective way to minimise ILUC. This may include: constraining the use of food crops, promoting the use of low ILUC feedstocks, including estimates of ILUC in GHG-emissions estimates, increasing land productivity and utilising marginal land. Production of agricultural biomass (i.e. current crops used for biofuels, purpose-grown energy crops and agricultural residues used for bioenergy in the UK) has the potential to cause both positive and negative impacts on biodiversity. Biodiversity impacts can occur where the biomass is grown, with use of marginal land being a particular concern. They can also occur elsewhere as a result of intensification of land use and ILUC. Much research has focused on the impact at a species level, particularly in relation to birds, butterflies and plants. The degree and nature of the impact (positive or negative) is to some degree inevitably specific to individual taxonomic groups and species. SRC and energy grasses are generally reported as supporting a wider abundance and diversity of flora and fauna when compared to conventional arable agriculture. Oil palm plantations are less species-rich than primary or secondary forest. Despite increasing interest at the science-policy interface in integrated landscape-scale thinking, there remains less research at a landscapescale than at a site-scale of the impact of producing agricultural biomass. In the UK, concerns have focused on the water use of perennial energy crops, and their impact on water availability. In general, water use of SRC is higher than arable crops but lower than other forest types. Miscanthus appears to use less water than SRC, however, yields are water limited in many areas of the UK. Catchment-scale impacts of SRC plantations on hydrology have been suggested to be negligible, as long as they are not planted in extensive areas of a single catchment. Flood-risk reduction from SRC plantations and buffer strips is a potential benefit of SRC. SRC has been suggested as having potentially positive benefits for improving water quality in catchments due to the lower fertiliser and pesticide inputs than are used for traditional crops and its ability to intercept pollutants in surface water runoff when used as a riparian buffer strip. Miscanthus, switchgrass and reed species have also shown potential to improve water quality either through their use in buffer strips or as a stand-alone crop.


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Table of contents 1

Introduction ................................................................................................................ 1 1.1 Themes .............................................................................................................. 1

2

Methodology ............................................................................................................... 4 2.1 Overview ............................................................................................................ 4 2.2 Literature sources and selection of relevant documents ..................................... 4 2.3 Ranking the reliability of data sources ................................................................ 5 2.4 Ranking confidence in evidence across multiple papers..................................... 7 2.5 Theme summaries ............................................................................................. 7

3

Current state of the market ........................................................................................ 8 3.1 Summary of current issues ................................................................................. 8 3.2 Confidence in the results ...................................................................................13 3.3 Trends in the information...................................................................................13 3.4 Evidence gaps ..................................................................................................13 3.5 Suggestions for further research .......................................................................13

4

UK agricultural production impacts .........................................................................15 4.1 Summary of current issues ................................................................................15 4.2 Summary of information in the literature ............................................................16 4.3 Confidence in the results ...................................................................................18 4.4 Trends in the information...................................................................................19 4.5 Evidence gaps ..................................................................................................19 4.6 Suggestions for further research .......................................................................19

5

Socio-economics.......................................................................................................21 5.1 Summary of current issues ................................................................................21 5.2 Summary of information in the literature ............................................................22 5.3 Confidence in the results ...................................................................................25 5.4 Trends in the information...................................................................................25 5.5 Evidence gaps ..................................................................................................26 5.6 Suggestions for further research .......................................................................26

6

Greenhouse-gas mitigation potential ......................................................................27 6.1 Summary of current issues ................................................................................27 6.2 Summary of information in the literature ............................................................28 6.3 Confidence in the results ...................................................................................33 6.4 Trends in the information...................................................................................34 6.5 Evidence gaps ..................................................................................................34 6.6 Suggestions for further research .......................................................................34

7

Land-use change .......................................................................................................35 7.1 Summary of current issues ................................................................................35 7.2 Summary of information in the literature ............................................................36 7.3 Confidence in the results ...................................................................................39 7.4 Trends in the information...................................................................................39 7.5 Evidence gaps ..................................................................................................39 7.6 Suggestions for further research .......................................................................40

8

Biodiversity................................................................................................................41 8.1 Summary of current issues ................................................................................41 8.2 Summary of information in the literature ............................................................42


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8.3 8.4 8.5 8.6

Confidence in the results ...................................................................................44 Trends in the information...................................................................................44 Evidence gaps ..................................................................................................45 Suggestions for further research .......................................................................45

9

Water use ...................................................................................................................47 9.1 Summary of current issues ................................................................................47 9.2 Summary of information in the literature ............................................................47 9.3 Confidence in the results ...................................................................................49 9.4 Evidence gaps ..................................................................................................49 9.5 Suggestions for further research .......................................................................49

10

Water quality..............................................................................................................50 10.1 Summary of current issues ................................................................................50 10.2 Summary of information in the literature ............................................................50 10.3 Confidence in the results ...................................................................................51 10.4 Evidence gaps ..................................................................................................52 10.5 Suggestions for further research .......................................................................52

11

Further gaps identified..............................................................................................53 Summary of air quality issues ....................................................................................... 2 References ................................................................................................................... 5 Literature searches....................................................................................................... 8 Primary screening on titles and abstracts ....................................................................19

Appendices Appendix 1: Air quality Appendix 2: Detail of literature searches Appendix 3: Organisations that provided information Appendix 4: Glossary Appendix 5: Current state of the market evidence-base spreadsheet Appendix 6: UK agricultural production impacts evidence-base spreadsheet Appendix 7: Socio-economics evidence-base spreadsheet Appendix 8: Greenhouse-gas mitigation potential evidence-base spreadsheet Appendix 9: Land-use change evidence-base spreadsheet Appendix 10: Biodiversity evidence-base spreadsheet Appendix 11: Water use evidence-base spreadsheet Appendix 12: Water quality evidence-base spreadsheet


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1 Introduction The aim of this project was to conduct a Rapid Evidence Assessment (REA) of research into the issues surrounding the production of feedstocks (both imported and home-grown), currently used in the UK for bioenergy in order to provide a common evidence base for use by Defra and other government departments. “REAs provide a balanced assessment of what is already known about a policy or practice issue, by using systematic review methods to search and critically appraise existing research. They aim to be rigorous and explicit in method and thus systematic but make concessions to the breadth or depth of the process by limiting particular aspects of the systematic review process”1.

1.1 Themes The review focused on impacts on agricultural land and covered the themes shown in Table 1-1. Table 1-1: Themes covered by the review Theme Current state of the market

Focus    

 UK agricultural production impacts

Socio-economics

      

Demand for feedstocks Availability of feedstocks (home grown versus imported) Potential for UK production to sustainably replace imports Economics of biofuels production Barriers to farmer adoption of biofuels crops Potential land requirements Availability of land for production Interaction with food production Potential for integrated production systems Where combustion requirements have an impact on crop quality Impacts from adoption (e.g. employment, inequality, food security) The social barriers to adoption (lack of knowledge or behavioural barriers

Greenhouse-gas (GHG) mitigation potential

 

GHG benefits against status quo Costs per tonne of carbon abatement

Land-use change

      

Definitions Main issues identified Current policy/ legislation Direct monitoring of LUC Modelling of indirect LUC (ILUC) Schemes to manage/ verify sustainable production Risks from contaminated feedstocks e.g. aflatoxin-infected corn, dioxin-contaminated vegetable oils Species Habitat area Habitat disturbance Pollution Invasion. Habitat connectivity.

Air quality*1 Biodiversity

1

     

http://www.civilservice.gov.uk/networks/gsr/resources-and-guidance/rapid-evidence-assessment/what-is


1


Theme Water use

Focus  

Water use Flood risk

Water quality

 

Water quality Effects of manure and wastewater application on water quality

Forestry was considered out of scope and anaerobic digestion (AD) was excluded, as AD has been an active area of research for Defra and assessments of impacts on agriculture from AD are already available2. Conversion issues are also important but were excluded. A summary of air quality issues associated with combustion of bioenergy feedstocks based on current information available to experts in Ricardo-AEA is included as Appendix 1.

1.2 Crops and residues The following crops and residues were included in the scope of the project: Dedicated energy crops grown in the UK     

Short-rotation coppice (SRC) willow SRC poplar Miscanthus Panicum (switchgrass) Phalaris (reed canary grass)

Crops grown in the UK that can be used for food or energy   

Sugar beet Oil-seed rape Wheat

Imported feedstocks    

Palm oil from Indonesia Corn ethanol from the USA and Ukraine Sugar cane from Brazil and Guatemala Used cooking oil

Agricultural residues   

Chicken litter Straw Contaminated or damaged crops

Non-agricultural residues 

Tallow.

1.3 The report This report provides an overview of the REA methodology employed and then stand-alone summary chapters in relation to each theme. There is some repetition between the theme summaries where issues are pertinent to more than one theme.

2

http://randd.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectID=17396#Description and http://sciencesearch.defra.gov.uk/Default.aspx?Menu=Menu&Module=More&Location=None&Completed=0&ProjectID=18631


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The purpose of each theme chapter is to provide a high-level summary of the topic, including:       

Current issues Information in the literature Confidence of the information reviewed Trends Evidence gaps Current research Suggestions for further research.

Each theme chapter is supported by an evidence- base spreadsheet, included as appendices to the report, which list the key references that have been identified and selected for use in this review. In this report, we have used the following definitions:  ‘Bioenergy’ – both biomass and biofuels  ‘Biofuels’ – crops used for liquid fuels  ‘Biomass’ – crops used for heat and power.


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2 Methodology 2.1 Overview The methodology employed by this project was broadly consistent with civil service guidance on REAs3 and was undertaken in three phases: an assessment of existing UK research on bioenergy and biofuels; a thematic synthesis of the evidence; and a gap analysis. Figure 2-1: Summary of methodology Define the scope and boundary of the search Define the search terms Literature search results High-level selection criteria

Retained literature

Team experts

DEFRA Steering group

Definition of themes

Literature categorised by theme in literature spreadsheet

Thematic synthesis Gap analysis

This section briefly describes how relevant documents were identified and selected, and the specific methodologies used to rank: 1. Reliability of data sources 2. Confidence in evidence across multiple papers.

2.2 Literature sources and selection of relevant documents Relevant literature was identified from: 

3

Abstract and citation databases: Scopus, Web of Science and Science Direct

http://www.civilservice.gov.uk/networks/gsr/resources-and-guidance/rapid-evidence-assessment/how-to-do-a-rea


4


 

Suggestions by key bioenergy research procurement organisations consulted as part of this work. The organisations that provided information are listed in Appendix 2 Literature already known to Ricardo-AEA experts.

The literature search involved the following steps:  







 



Defra Steering Group was consulted on search terms (identified by experts) for each theme before they were deployed The search terms were then refined as the searches progressed, depending on the number of references located and their relevance. The final search terms are given in Appendix 3 Primary screening for relevance of the literature returned was then carried out through assessment of the titles and abstracts. This was done by comparing the titles and abstracts against the exclusion criteria in Appendix 3. In this way, references that were obviously not relevant to the theme were excluded The references that were deemed of relevance following screening were captured in an evidence-base spreadsheet. This spreadsheet contained all basic information on the reference, such as author, title, year Supplementary sources of relevant information were also identified by the project team and consultees from their expert knowledge. These were added to the evidence-base spreadsheets for each theme Further screening of the list of documents included in the evidence-base spreadsheets was then conducted by each theme expert This further screening was carried out in order to identify a long list of the papers addressing all feedstocks and all issues relevant to each theme covered by the literature From this long list, approximately ten to fifteen key references for each theme were selected for full review on the basis of their ‘pedigree score’ (the reliability of information from which their data were derived – see Section 2.3).

The evidence-base spreadsheets for each theme provided in Appendices 5-12 show the long list of relevant references with the key references highlighted at the top.

2.3 Ranking the reliability of data sources In order to choose the best papers for the full review, the pedigree of relevant papers was assessed. Our assessment of primary research (‘non-review’) papers is based on the methodology of van der Sluijs et al (2002). A different scoring methodology for review papers was developed following the same principles for use in this REA. Both methodologies are described below. As the scoring for review and non-review papers was different, review and non-review papers were distinguished from one another in the evidence-base spreadsheet and the scores for review and non-review data pedigree were presented in different columns.

2.3.1 Data pedigree of non-review papers The pedigree of the information was evaluated by scoring key elements of the underlying data between 0 and 4 on four aspects, using the framework in Table 2-1 below. Data pedigree was established from the sum of the scores of the key inputs. A combined score of 0 – 4 was poor; 5 – 8 moderate; 9 – 12 good; and 13 – 16 very good. These scores were recorded in the evidence-base spreadsheet in order to identify those references ranked highest for use in the subsequent synthesis and gap analysis.


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Table 2-1. Pedigree-matrix to evaluate data and evidence for non-review papers Strength indicators

Score

Proxy

Empirical

Method

Validation

4

An exact measure of the desired quantity

Controlled experiments and large sample of direct measurements

Best available practice in wellestablished discipline

Compared with independent measurements of the same variable over long domain

3

Good fit or measure

Historical/field data, uncontrolled experiments, small sample of direct measurements

Reliable method, common within established discipline, best available practice in immature discipline

Compared with independent measurements of closely related variable over shorter period

2

Well correlated, but not measuring the same thing

Modelled data, indirect measurements

Acceptable method but limited consensus on reliability

Measurements not independent proxy variable with limited domain

1

Weak correlation, but commonalities in measure

Educated guesses, Preliminary Weak and very indirect indirect methods with validation approximations, rule unknown reliability of thumb

0

Not correlated and not clearly related

Crude speculation

No discernible rigour

No validation performed

2.3.2 Data pedigree of review papers The following scoring system (Table 2-2) was developed for review papers. Table 2-2. Pedigree-matrix to evaluate data and evidence for Review papers Strength indicators

Score

Research question

Search strategy

Weighting

Summary of results

3 Clearly formulated question

Explicit, systematic Systematic scoring Quantitative metasearch strategy of ‘data pedigree’ analysis, caveats and confidence and assumptions detailed

2 Research question broadly identified

Limited search strategy

Qualitative consideration of strength and quality of data

1 Research question not identified

Selected evidence only

Limited Limited analysis, consideration of difficult to trace strength and quality evidence of data

Qualitative analysis, caveats and assumptions detailed

A combined score of 4-6 was described as poor; 7-9 moderate and 10-12 good.


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2.4 Ranking confidence in evidence across multiple papers In order to comment on consistency of evidence across each theme, we used the methodology associated with the Intergovernmental Panel on Climate Change’s Fifth Assessment Report4 to rank confidence in evidence across multiple papers. We used the following dimensions: the type, amount, quality, and consistency of evidence (summary terms: “limited,” “medium,” or “robust”), and the degree of agreement (summary terms: “low,” “medium,” or “high”). These were combined using the matrix in Table 2-3 below to give an overall confidence rating (high, medium, low). Generally, evidence is most robust when there are multiple, consistent independent lines of high-quality evidence. Confidence ratings were provided on a separate worksheet in the Evidence Base spreadsheets. Table 2-3: A depiction of evidence and agreement statements and their relationship to confidence

Agreement

HIGH

LOW

High agreement Limited evidence

High agreement Medium evidence

High agreement Robust evidence

Medium agreement Limited evidence

Medium agreement Medium evidence

Medium agreement Robust evidence

Low agreement Low agreement Low agreement Limited evidence Medium evidence Robust evidence Evidence (type, amount, quality, consistency)

HIGH

White is ‘low’, light grey is ‘medium’ and darker grey is ‘high’.

2.5 Theme summaries Each theme chapter is intended to be a stand-alone summary, as described in Section 1.3. The literature review did not include detailed review of policy papers, however, these have been referred to in the theme summaries to provide context and background. As part of the project, we contacted key organisations to discuss current UK research into bioenergy feedstocks and, where relevant, information on current research has been included in the theme summaries. The organisations that provided information are listed in Appendix 2. It should be noted that there is a considerable amount of relevant ongoing research in the UK and new research is also being commissioned, therefore, gaps identified may be the subject of research projects in the near future.

4

Mastrandrea, M.D., C.B. Field, T.F. Stocker, O. Edenhofer, K.L. Ebi, D.J. Frame, H. Held, E. Kriegler, K.J. Mach, P.R. Matschoss, G.-K. Plattner, G.W. Yohe, and F.W. Zwiers, 2010. Guidance note for Lead Authors of the IPCC Fifth Assessment Report on consistent treatment of uncertainties. Intergovernmental Panel on Climate Change (IPCC). Available at: http://www.ipcc.ch/pdf/supporting-material/uncertainty-guidancenote.pdf


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3 Current state of the market 3.1 Summary of current issues Demand for bioenergy in the UK is driven by the need to increase the contribution of renewable energy in the UK energy mix and to reduce GHG emissions from energy generation. Although there are no targets for bioenergy from heat and power, the UK Biomass strategy and the Committee on Climate Change foresee a significant contribution to UK energy production from bioenergy up to 2050; perhaps up to 350,000ha of energy crops by 2020 and 800,000ha of energy crops by 2050. The current UK target for renewable transport biofuels is 4.75% by volume of liquid road transport fuels by 2014, which may rise to 10% by 2020. The current renewable transport fuel supply comprises mainly bioethanol and biodiesel. A total of 32,000ha of UK wheat, oil seed rape and sugar beet was used to produce biofuels in 2012/13. The current trend is for more biodiesel to be produced from wastes and residues, due to sustainability concerns. No advanced biofuels made from lignocellulosic biomass are currently produced in the UK, although in the 2020 to 2050 timeframe it is envisaged that biofuel production will move towards advanced biofuels. Currently bioenergy for heat and power is mainly produced from imported solid biomass. There is a robust but limited supply of UK wastes and straw currently used for heat and power production5. The current supply of SRC and Miscanthus is very low, with about 10,000ha planted in the UK. The use of UK waste and straw for bioenergy has advantages as set out in the Government’s Bioenergy Strategy. However, the available supply of UK wastes and straw for bioenergy is predicted to increase only slightly between now and 2050. To substantially increase UK bioenergy contribution will therefore require energy crops and/ or increased use of woody products such as Short Rotation Forestry (SRF) and forestry residues. Modelling suggests that there is a large area of land suitable for energy crop production in the UK. The availability of this land depends on a range of assumptions about the amount of land needed for food and feed production and on what sustainability constraints are applied; estimates of suitable and available land range from 0.57Mha to 8.5Mha. From a farmers perspective there is no issue with producing wheat, sugar beet and oil seed rape for energy uses, as these crops are well known and can be sold through normal channels. There are a range of issues for farmers in producing SRC and Miscanthus. Firstly, SRC and Miscanthus are often not economically competitive with current farm enterprises. This is the case even with establishment grants, although recent research has shown that SRC and Miscanthus can be competitive in a number of situations, particularly on lower quality land. However, utilising low quality land has potential biodiversity implications (see biodiversity theme summary). Even where SRC and Miscanthus are economically attractive there remain a range of barriers preventing farmers from growing the crops. The most important of these are; a lack of a stable and long term market, unwillingness to tie up land for long periods and the risk associated with unknown crops. The low rate of uptake of SRC and Miscanthus to date demonstrates that there is unlikely to be progress in commercial SRC and Miscanthus production unless these barriers are overcome.

5

Ofgem Annual sustainability report. https://www.ofgem.gov.uk/publications-and-updates/annual-sustainability-report-201011?docid=318&refer=Sustainability/Environment/RenewablObl/FuelledStations/ro-sustainability. ARUP 2014- Advanced biofuels feedstocks- an assessment of sustainability.


8


A summary of evidence reviewed for the current state of the market chapter is available as Appendix 5 to this report.

3.1.1 UK feedstock demand Demand for bioenergy in the UK is largely driven by requirements to increase the share of renewable energy in the UK to 15% of gross final consumption of energy by 2020 and to reduce UK GHG emissions by 80% by 2050.6 The latest estimate of the UK Renewable Energy requirement in 2020 is 223TWh to 230 TWh7, with a sub target of about 44TWh contribution from liquid road transport fuels8 There are currently no specific bioenergy targets in the UK for electricity and heat production. However, the 2012 UK Bioenergy Strategy envisages a substantial contribution to renewable energy targets from bioenergy, subject to sustainability constraints9, and the Committee on Climate Change (CCC) Bioenergy Review in 2011 envisages between 300,000ha and 800,000ha of energy crops by 2050, delivering between 15TWh and 70TWh, depending on the scenario considered. The CCC also envisages the use of UK food and fodder crops for bioenergy reaching a maximum 7TWh in 2020 (equivalent to about 400,000ha wheat) and then reducing to zero by 2050. The Renewable Transport Fuel Obligation ( RTFO) has a current target of 4.75% renewable transport fuel by volume in the UK supply by 2014. This may be raised to 10% by 2020, depending on the outcome of discussion on ILUC at EU level, but this is likely to include a cap of 5% on the contribution of biofuels from food and fodder crops. Additional biofuels would have use waste feedstocks or be advanced biofuels made from lignocellulosic biomass such as straw or SRC or Miscanthus.

3.1.2 Current UK bioenergy supply from domestic crops The current estimated areas of UK grown crops used for biodiesel and bioethanol production are shown in Table 3-1 below10. Table 3-1: Current estimated areas of UK-grown crops used for biodiesel and bioethanol production UK grown Crop

Area for biofuels in 2012/ 2013, Crop (ktonnes) (kha)

% UK production

Oilseed rape (OSR)

2.1

7

0.3

Sugar beet (SB)

10.4

631

9

Wheat

19.6

132

1

The area of OSR used for biodiesel production has been decreasing from a maximum of 17,700 ha in 2009, with the majority of the feedstock now coming from used cooking oil (UCO) and tallow. The area of wheat use for bioethanol has been variable, since the UK’s first wheat to ethanol plant has been closed intermittently due to market conditions including high wheat prices and cheap bioethanol imports. At future planned levels of operation wheat

6

The EU Renewable Energy Directive (RED) requires that the UK has a 15% share of energy from renewable sources in gross final consumption of energy in 2020. The 2008 UK Climate Change Act requires an 80% cut in the UK’s carbon emissions by 2050 below 1990 levels. 7 UK Renewable Energy Roadmap update, December 2012. 8 R-AEA Biofuels Modes project 3 for DfT. July 2011. 9 Although not quantified in the 2012 strategy, the earlier 2007 Strategy suggests that up to 350,000ha of energy crops could be grown in the UK by 2020 producing 17.2TWh primary energy. 10 Defra 2013


9


to bioethanol plants in the UK would require about 1.6 million tonnes of wheat11. The area of SB has been fairly consistent. Currently Miscanthus, SRC and straw have been utilised in heat and power applications. Estimated production and utilisation in UK power stations are shown in Table 3-2 below. Table 3-2: Estimated production and utilisation of Miscanthus, SRC and straw in UK power stations UK grown crop

Area in UK 2012/ 2013 (kha)

Crop (ktonnes)

Utilised in UK power stations (ktonnes)

Miscanthus

7

70

45

SRC

2.5

15

14

Straw

215

In addition, a number of straw fired plants are in development, which will require an additional 667 thousand tonnes of straw by 2020. It can be seen that when there is demand, a substantial quantity of annual crops and straw can be delivered to the UK bioenergy market, but that Miscanthus and SRC are still at a very low level of production in the UK.

3.1.3 Potential UK bioenergy feedstock supply Potential production of bioenergy crops in the UK is discussed in detail in the ‘UK Agriculture production’ theme. In summary:    





A number of recent studies have considered the potential of land in the UK to produce energy crops Estimates for land suitable for wheat, OSR and SB are lower than for SRC and Miscanthus, since lignocellulosic crops are more suited to lower grade land About 8.5 Mha out of a total of 17.2Mha of total utilised agricultural area in the UK is estimated to be suitable for SRC or Miscanthus There is a wide range of estimates of suitable and available land, ranging from 0.57Mha to 2.5Mha. The differences are due to the range of assumptions made about sustainability requirements, economic feasibility and what land is required for other purposes including food/ feed There is a range of estimates of yields that would be achieved by lignocellulosic crops. Yield depends on the variety, land conditions and agronomy. To date yields in commercial situations have been significantly lower than in trials, with typical values being 12 odt/ha for Miscanthus and 8 odt/ha for SRC willow Assuming an average yield of 10odt/ha for energy crops and an average Calorific Value of 18GJ/odt, the potential primary energy production from energy crops on the available land is estimated to be 103PJ- 450PJ or 28TWh- 125TWh.

The straw resource is estimated from the area of cereal crop production. Current estimates of total straw available for collection in the UK are in the range of 7.4Mt to 11Mt (14TWh) per year. However, there is considerable debate about the amount of straw that can be harvested sustainably, with sustainable removal rates of 25% to 60% being quoted. Taking current alternative uses of straw into account, and assuming 50% can be removed sustainably on average, recent estimates of straw available for bioenergy are about 2.5 Mt. 11

HGCA, pers comm.


10


The future UK straw availability depends on the area of cereal grown and livestock demands, but is expected to remain fairly constant to 2020. Recent research concludes that there is a robust but limited UK bioenergy resource available from straw and wastes. These resources are not predicted to increase significantly to 2050. To increase bioenergy feedstock production significantly in the UK in the medium term requires increased production of energy crops and/ or forestry products.

3.1.4 Imported feedstock available to the UK Currently a large proportion of biofuels and solid biomass feedstock for power is imported. Researchers have attempted to determine if there will be sufficient availability of imported feedstock in the future to meet projected UK demand, in a world where there is likely to be increased global demand for biomass. Researchers first estimated the total biomass resource available, then the amount that would be available on the international bioenergy market taking domestic country/ region use and competing markets into account. Finally they estimated the proportion of this that would be available to the UK. The results should be regarded as speculative, as they are subject to a number of assumptions about the development of energy crops, country/regional biomass use and development of trade in biomass. Results show that there is sufficient resource to meet UK demand, but that much of that resource is from energy crops that have not yet been planted. Potential of imported crops is projected to increase to 2035 and then decrease to 2050 as the UK market share decreases.

3.1.5 Market prices for UK bioenergy feedstocks Feedstock prices have been reviewed recently12. These are consistent with market sources and are summarised in Table 3-3 below. Table 3-3: Feedstock prices Feedstock

Current price (£/tonne)

Point in supply chain

Straw

63 (48 to 75)

Farm gate

Miscanthus

53

Farm gate

SRC

50

Farm gate

UCO

724

Free on Board

Animal fats cat I and II

480

FOB traded

13

(FOB) traded

Prices for wheat, sugar beet and oil seed rape for bioenergy are assumed to be the same as feed wheat, sugar beet and oils seed rape for other purposes.

3.1.6 Farm economics of energy crop production Research concentrates on SRC and Miscanthus, as agronomy and economics of wheat, sugar beet and oil seed rape are well known. Work to date on SRC and Miscanthus has comprised bottom up estimates of cost based on materials and labour costs. Income from these perennial crops has been annualised for comparison with annual crops. However, the delay of up to four years in starting to obtain income from perennial crops is seen as an additional problem in terms of the farm economics of these crops.

12 13

ARUP URS 2013 With FOB traded, the buyer pays for transportation of the goods.


11


Gross annual equivalent margins for SRC and Miscanthus compare poorly with individual annual crops such as wheat, OSR, SB and with the average arable rotation, at current market prices and average UK yields14, even when establishment grants are included. SRC and Miscanthus can compete with lower margin enterprises such as renting out grassland and arable production on poor quality land. Recent work has compared yields of crops on a regional basis and predicts where Miscanthus and SRC will be competitive at current and increased prices. There is a strong regional variation, and increasing the price of Miscanthus in particular to £70/t gives a large increase in the area that can be economically competitive. No research was found into the impacts on farm economics of integrating energy crops into existing farm enterprises e.g. by introducing novel annual energy crops into arable rotation or by intensifying use of grassland.

3.1.7 Barriers to farmer adoption Farmers in the UK perceive no barriers to production of wheat, OSR and SB for energy. Production meets current EU Renewable Energy Directive (RED) sustainability criteria through voluntary schemes (see the Land Use Change theme summary), and indeed they often do not sell a crop for a specific end use. Farm economics remain a major barrier to production of SRC and Miscanthus in the UK. However, there are also a range of other barriers. These are summarised in Table 3-4 below, and have been confirmed in recent surveys with UK farmers. Suggestions from farmer surveys and the literature for overcoming these barriers have also been summarised Table 3-4: Barriers to production of SRC and Miscanthus suggested in the literature. Barriers

Mitigation Literature

options

suggested

in

the

Economics compared with current enterprises, Utilise low productivity land for energy crops to particularly arable rotations. Time from increase overall farm income. establishment to income generation. Long term guaranteed support for production. Income support for early years for perennial crops. Unwillingness to change/ Doesn’t fit with existing Integration with existing enterprises to boost business plan. income/ yields. Risk from unknown crops/ tying up land for long Learn from experience of early adopters e.g. via periods/ lack of equipment and experience. case studies/ farm visits. Lower labour requirements. Update and promote establishment/ management guidelines. Uncertain markets

Stable long term bioenergy policy.

Moral or sustainability concerns

Current low levels of SRC and Miscanthus production, and low levels of interest in growing these crops from farmers surveyed show that these barriers remain serious and need to be addressed if significant UK production of SRC and Miscanthus is to be achieved.

14

Alexander 2013, SAC 2009.


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3.2 Confidence in the results This is based on an assessment of the quality of the evidence, and agreement between the different sources reviewed (see Table 3-5). Table 3-5: Confidence in evidence of the current state of the market Feedstock

SRC and Miscanthus Wheat, sugar beet and oil seed rape straw UCO and tallow

Subtheme UK feedstock demand

Current UK bioenergy supply from domestic crops

Potential UK bioenergy feedstock supply

Imported feedstock available to the UK

Market prices for UK bioenergy feedstocks

Farm economics of energy crop production

Barriers to farmer adoption

Low

High

Medium

Low

Medium

Medium

High

Low Medium

High High

Medium Medium

High High

High

Medium

High

Medium

High

Medium

3.3 Trends in the information 

Reduction in demand for OSR for biofuels and increase in use of UCO as a result of incentives to use wastes.

3.4 Evidence gaps 3.4.1 Described in the literature  

Economic performance of SRC and Miscanthus in commercial situations on lower quality land. Up to date guidelines for SRC/ Miscanthus production and management.

3.4.2 Gaps not described in the literature  

Integrated production of bioenergy/ arable crops/ livestock. Review of biomass availability for export on a country by country basis.

3.5 Suggestions for further research 3.5.1 Described in the literature As described in 3.4.1.

3.5.2 Further suggestions  

Look at integrated production of bioenergy/ arable crops/ livestock to see how this affects yields and economics. Investigate alternative annual crops e.g. triticale for bioenergy production and increased crop rotation options.


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3.5.3 Ongoing research    



How to add value to bioenergy crops for farmers who are growing them – Institute of Biological, Environmental and Rural Sciences, Aberystwyth University (IBERS). How to provide farmers with up to date information on energy crop production – IBERS Review on straw incorporation – HGCA Value Chain Model in development by Supergen Bioenergy for Energy Technologies Institute (ETI) is looking at the economic and carbon impact of sustainably developing UK biomass resources and converting these to a range of energy vectors. The model is not published, but it would be worth exploring what access Defra might have. Estimate the potential size of the international bioenergy trade in the future using the TIAM-UCL global energy systems model. Extension of the E4Tech Biomass Systems Value Chain Model, supported by Engineering and Physical Sciences Research Council (EPSRC) Supergen.


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4 UK agricultural production impacts 4.1 Summary of current issues An estimated 7.5 million (M) oven-dry tonnes (odt) of bioenergy crops, equivalent to 3.5 M odt of dedicated bioenergy crops for electricity and 4.0 M odt for bioethanol, would be required to meet the aspirational UK Renewable Energy Strategy targets of 15% of all energy and 30% of electricity demand to be met by renewable sources by 2020 and the Renewable Transport Fuel Obligation of at least 4.75% (by volume) of all transport fuel to be biofuel by 2014. To meet these requirements the UK Biomass Strategy15 concluded that 0.35 M ha of perennial energy crops are needed by 2020, together with an estimated 0.74 M ha for transport fuel from biofuel. These estimates of land requirement were based on assumed average yields of 10 odt ha-1 for short-rotation coppice (SRC) and 8 odt ha-1 for wheat. The European Environment Agency has predicted that 0.80 M ha in the UK could be made available for bioenergy cropping by 2010, rising to 1.10 M ha in 2020 and 1.60 M ha in 2030. These predictions are set against current bioenergy crop production, comprising willow from SRC and Miscanthus, of 10,000 ha, indicating that a large increase in area of production is needed to meet demand. The main question is: can these demands for bioenergy crops be met without compromising food production or other environmental initiatives by requiring conversion of land from food production or sensitive habitats including permanent grassland? In this theme, literature has been reviewed to identify evidence on the area of land required for cultivation of bioenergy crops, the area of land available for bioenergy crops and the impacts of growing bioenergy crops on food production. Perennial crops are considered preferable to annual crops such as wheat and oilseed rape as a source of bioenergy since perennial crops have a better energy ratio and more effective mitigation of greenhouse-gas (GHG) emissions. Considerable work has been carried out to identify areas of the country most suitable for the production of the perennial bioenergy crops Miscanthus and SRC, mainly willow. Estimates are available of the area of land suitable for the cultivation of perennial bioenergy crops and also of the land area required to meet the targets for renewable energy from bioenergy crops. Most agricultural land, up to 8.5 M ha, is considered suitable for the cultivation of bioenergy crops. Estimates of the area of land available differ greatly depending upon the assumptions made. Scenarios that prioritise food production and/or nature conservation estimate the area of land remaining for bioenergy crops may be between 0.57 and 1.64 M ha. These scenarios envisage continued increases in the productivity of agricultural crops as a result of which the area of land needed to produce food may decrease creating surplus land for bioenergy crops. The area of land needed for bioenergy crops by 2020 in order to meet renewable energy objectives is estimated to be 0.80 M ha. Work has been carried out to measure the yields of many varieties of Miscanthus, willow and poplar and to assess their suitability for cultivation in different agroclimatic regions of the UK. Growing the most appropriate bioenergy cultivars is likely to reduce the area of land needed to meet bioenergy targets. Work continues into the physiology and genetic variability of perennial bioenergy crops in order to identify traits which can further increase their yield and energy content. No evidence was found of any work assessing the impact of combustion requirements on crop quality although longer term breeding is evaluating traits that make perennial crops more suitable for processing as biofuels.

15

This was published in 2007 and is since replaced with the Bioenergy Strategy, which does not include land area estimates.


15


Work has been carried out to determine the willingness of farmers to grow bioenergy crops, the reasons for not growing them and the conditions under which farmers would be willing to sell straw as a bioenergy feedstock. A fixed price of £50 t−1 was the minimum contract price required by farmers to sell straw. Contracts of either 1 or 3 years and the stipulation of a fixed area of straw to be supplied were the most frequently cited preferences by farmers. A summary of evidence reviewed for the UK agricultural production impacts chapter is available as Appendix 6 to this report.

4.2 Summary of information in the literature Table 4-1 below summarises reported estimates of either the land area required or the land area available for the production of bioenergy crops . Table 4-1: Studies of the land required or available for bioenergy crops, including an EU wide study Land required (M ha)

Authors

Objective

Welfle et al. (2014)

Modelled 4 scenarios, prioritising food security, economic development, conservation and bioenergy. Results for 2010 Modelled potentially available land for perennial bioenergy crops under current and forecast climates GIS modelling of the area of land suitable for Miscanthus within 25 and 40 km of site of end use Modelled the theoretical maximum available land for Miscanthus and SRC Prioritised food production and nature conservation. Up to 50% of crop residues can be removed. Forecast to 2030 Identified ‘idle’ and marginal land that can be used for bioenergy without competing for food production Estimated the spatial supply of SRC 0.800 Estimated the implications of planting 350,000 0.350 ha of bioenergy as Miscanthus.

Lovett et al. (2013)

Thomas et al. (2013) Aylott and McDermott (2012) Fischer et al., 2010 FERA (NF0444), (2010) Aylott et al. (2010) Lovett et al. (2009)

Land available (M ha) 0.711 2.246 1.400 8.500 2.000 2.400 0.930 3.630 0.57 11% of area 0.868

7.100*

* England only Availability of land for production Recent estimates (2014) have been made of the area available for bioenergy crops in 2020 under four scenarios in which priority was given to: food security; economic growth; conservation; bioenergy production. The areas estimated were: food security scenario, 1.64 M ha; economic development scenario, 1.46 M ha; conservation scenario, 0.71 M ha; energy scenario, 2.25 M ha. A 2010 estimate indicated that by 2030 0.57 M ha of land would be available in the UK for bioenergy crops, around 11% of land forecast to be cultivated at that time. This was based on a scenario which prioritised food production and nature conservation and took account of forecast increases in productivity of agricultural crops. Up to 50% of crop residues were assumed to be used for biofuel production without risks for agricultural sustainability.


16


The area of land suitable for the production of Miscanthus and SRC willow in Great Britain was reported to be 8.50 M ha. This decreased to 6.4 M ha if Agricultural Land Class (ALC) Grades 1 and 2 land were excluded and decreased further to 1.4 M ha if ALC Grade 3 land was excluded. The approach did not allow the cultivation of bioenergy crops on key land use areas, but no constraint was imposed to maintain food production. The theoretical maximum available land for Miscanthus and SRC was also modelled at between 0.93 and 3.63 M ha. If planting is assumed to not take place below a gross margin of £526/ha for Miscanthus (at £60/odt) then the maximum area of land available will be reduced to 0.72-2.80 M ha. At a gross margin of £241/ha for SRC (at £60/odt) this figure decreases to 0.62-2.43 M ha. A study has also been carried out to determine the area of land viable for the cultivation of Miscanthus within 25 km and 40 km of the identified potential end uses of feedstock. The areas available within those radii, out of an estimated total of 2.50 M ha, were 2.00 M ha and 2.40 M ha within 25 and 40 km respectively. The results also indicated that potential generation exceeds the 2020 UK bioenergy generation aspirational target of 259 PJ, whichever radius is applied. However, the predictions assumed Miscanthus cultivation at all appropriate sites, with no policy interventions to limit transport distance. A survey of farmer attitudes found that 17.2% (11.9%) of farmers interviewed would consider growing, and 1.2% (0.4%) were currently growing, Miscanthus and SRC respectively. The main reasons cited for not growing dedicated bioenergy crops were impacts on land quality, lack of appropriate machinery, commitment of land for a long period of time and time that needs to elapse before financial returns are adequate to make the crops profitable. Potential land requirements The production of 7.5 M tonnes of bioenergy from SRC has been considered to be an achievable target for England. Such production would require 0.80 M ha and could be grown mostly on marginal lands, ALC Grades 4 and 5. Recently reported work modelled yields of the perennial bioenergy crops Miscanthus and the SRC species, willow, poplar, silver birch and Sitka spruce across GB under current and forecast climates to 2050. A combination of Miscanthus, SRC willow and poplar and short rotation forestry (SRF) poplar produced the greatest GB mean yields and out yielded all other bioenergy crop types for each designated 1 km2 location. No estimates were made of the land requirements of these crops to meet bioenergy targets but the results suggest that by using the optimum species in different climatic areas bioenergy may be produced over a smaller area than is suggested by forecasts based on the performance of only Miscanthus and SRC willow. Perennial crops are considered to be preferable to annual crops as a source of bioenergy since perennial crops have a better energy ratio and more effective mitigation of GHG. The predicted competition with food for finite land resource remains unresolved. Indications are that bioenergy could potentially contribute up to 7% of the UK demand for heat and electricity, but land will become an issue if it is deployed for liquid biofuels, as this is in addition to this figure. Academics have suggested that a clear strategy for land management is required. A farmer survey has also been carried which estimated the amount of straw farmers may be willing to sell for the production of bioethanol is 2.52 Mt if they are paid an acceptable price. The authors present the areas of crops grown in the UK that could provide straw for bioethanol, estimates of straw yield and the proportions of straw produced (54%) that could be supplied for bioethanol if the farmer’s requirements are met. These data could be used to calculate the reduction in nutrients returned to soil should straw be sold for bioethanol and the amounts and costs of additional fertilizer needed to replace those nutrients. Reducing residue returns to soil would be expected to lead to a decrease, albeit small, in soil organic matter. Applications of potash fertilizer would need to be increased (typically by 30-40 kg/ha) to compensate for the reduction in potash returned to soil.


17


Interaction with food production A comparison of the impacts of perennial and annual bioenergy crops, using the land use requirements identified, and assuming average yields for converted land, found that conversion of arable land to Miscanthus would result in a decrease in food production equivalent to 0.3 Mt of cereal. To meet the 2011 UK biofuel target of 27 PJ using wheat bioethanol, 3 Mt of cereal would be required. Producing 7.5 M tonnes of bioenergy from SRC should not compromise environmental sustainability or food production as the 0.80 M ha required could be grown mostly on ALC Grades 4 and 5 with just 5% grown on Grade 3 land. It has also been reported that replacing 10% of arable land, 20% of improved grassland and 100% of set-aside grassland in England and Wales with the three most productive SRC genotypes would yield 13 Modt of bioenergy annually (supplying 7% of UK electricity production or 48% of UK combined heat and power (CHP) production). There was no discussion of the impacts of this on food production although the published findings allow the reader to make their own conclusions on the potential reduction in food output that would arise from the change in land use. Empirical modelling using GIS has been used to produce a yield map and estimate regional energy generation potentials after masking out areas covered by environmental and socioeconomic factors which could preclude the planting of bioenergy crops. There were regional differences in the importance of different factors affecting bioenergy planting. Areas with the greatest bioenergy yields co-locate with food producing areas on high grade land. When such high grade land and unsuitable areas are excluded, a policy-related scenario for increased planting on 0.35 M ha utilised 4–28% (depending on the region) of lower grade land and would not necessarily greatly impact on UK food security. This area corresponded to 7.4% of the arable cropping area in England and was estimated as displacing 102,939 ha of winter wheat (5.5% of nationally planted area) and 26,799 ha of oilseed rape (5.9%). The total bioenergy yield equated to around 2.4% of total energy demand in 2005. Potential for integrated production systems Only one of the studies examined in detail considered integrated production systems. The authors concluded that ‘Planting a proportion of land on individual farms with energy crops (10 – 20%) offers the most practical route to increasing bioenergy production in the UK without unduly disrupting food production and the environment.’ This approach meets some of the recommendations of an earlier report, but did not advocate the concept of ‘regional biomass crop production zones’ that had been proposed. Crop yields and quality No explicit evidence was found to indicate that special cultivars or management techniques are required for farmers to meet bioenergy end user specifications. Work has been carried out to quantify yields of different perennial bioenergy crops on different soils and locations which can be used to choose regionally-appropriate bioenergy crops to optimize yield and minimize the land requirement. Further breeding of Miscanthus was modelled to have the potential to increase yield by almost 90%.

4.3 Confidence in the results We found only a moderate number of papers or reports on this theme. Papers reviewed often reported related work and were based on the same underlying data. An earlier review also noted that ‘there is considerable overlap between reports’. In consequence, confidence in some of these estimates is limited as they have defined the area available for bioenergy crops as the area suitable minus areas of land occupied by infrastructure or designated under some form of environmental or aesthetic protection without taking account of the need for food production. Only two studies attempted to estimate for the UK the area of land available while maintaining current food production.


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The confidence ranking (Table 4-2) based on review of individual papers and agreement across papers. Table 4-2: Confidence in evidence of the impact on agricultural production of biomass feedstocks Land available Land required for bioenergy for bioenergy crops crops

The impacts on food production

Adoption of integrated production systems

Bioenergy crop yields and quality

Medium

Low

Low

Medium

Medium

4.4 Trends in the information No trends can be derived from these results as studies were often based on widely different premises and hence the results are not comparable.

4.5 Evidence gaps 4.5.1 Described in the literature An earlier review of studies of the availability of bioenergy crops for energy purposes found that the high level assumptions were remarkably consistent and conservative but that there were also generic methodological problems that needed to be overcome: in particular inconsistent definitions of the land resource potentially available for the production of bioenergy crops and discrepancies in the scope of, and extent of, estimates of the proportions of land under different uses, i.e. arable crops, grassland, brownfield sites, etc. The previous review concluded that existing studies were imperfect, but that they exhausted the availability and quality of the underlying data. Earlier studies were considered to simply describe what might be possible; the level of effort (and policies) required to realise these increases were yet to be determined. Consequently, increasing the precision of estimates would require a major new data collection effort. It was also concluded that the dominant assumption that bioenergy can only proceed with negligible impact on other markets is untenable and merited further investigation. Another previous study concluded that while the UK has strength in basic crop science, in particular for food crops, including breeding, improvement and agronomy (including an understanding of the probable response to climate change), this has not been applied widely to likely dedicated bioenergy cropping systems. This considered that ongoing research within TSEC-BIOSYS and SUPERGEN-Biomass may address some of these gaps, but with limited long-term strategic vision. However, the author failed to take into account the detailed study, including a large number of field trials, funded by the DTI of yield potentials for a number of perennial bioenergy crops, or the GIANT-LINK project which is co-funded by Defra and industry.

4.5.2 Gaps not described in the literature Willow breeding work finished in 2010 and the breeders consider there is more to be gained in developing cultivars for marginal soils. More work to identify high value secondary products from willow could also improve the economics of this crop.

4.6 Suggestions for further research 4.6.1 Described in the literature Estimating the bioenergy resource potential is a highly interdisciplinary task and therefore a mix of approaches for different bioenergy resources are needed in order to quantify Ref: Ricardo-AEA/R/ED59367/Issue FINAL

19


interactions with existing markets, the technical and agronomic constraints and the potential opportunities. There is also a need for expert judgement when compiling and combining multiple bioenergy resource estimates as no one organisation is likely to have the necessary breadth of expertise in all sectors. Bioenergy crops need to be viable to both farmers and the energy sector. Currently crops such as Miscanthus and SRC are the most common option. These are suited to use in electricity or heat generation, but energy crops for alternative uses in energy (e.g. second generation biofuels) and more farmer friendly crops should also be considered. Such crops include reed canary grass and switchgrass, which are established from seed with lower costs and using conventional equipment. Further work is necessary to ascertain yields and performance on a range of ALC land classes. A slightly smaller yield potential may be an acceptable downside if it means that take-up is better. Such research needs to be linked to the best use of the biomass produced and the needs of the energy sectors.

4.6.2 Further suggestions In light of the need for an interdisciplinary approach to estimating the amount of land available for bioenergy crops without compromising food production there is clearly a need for a more explicit UK study. Such a study would combine assessing forecast demands for food within the UK and trends in production to determine the extent to which future demand for food can be met and the extent to which increases in productivity may release land for bioenergy crops. Such work would utilise the findings of work which identified the most productive bioenergy crops for the different regions of the UK and also make use of methods developed to take account of the needs for land for urban, transport, woodland and other uses which would preclude the cultivation of bioenergy crops, together with assessments of the impact on the production of food crops. Finally a comparison should be made to identify grid squares where the gross margin from bioenergy crops may exceed that for food crops and hence where farmers may be likely to replace food crops with bioenergy and hence assess the impact on food production. The case study carried out for Marston Vale in England gave primacy to the production of food for direct human consumption, but not livestock feed. Such an approach, if applied to the UK, would give a more realistic assessment of the land available for biofuels but primacy would also need to be given to producing feed for livestock as it cannot be assumed that current livestock production can be maintained by the use of co-products from liquid biofuel production. Detailed work has been carried out to determine yield potentials of a range of perennial bioenergy crops, and to identify the best choice of bioenergy cops for different locations in the UK. However, such work is of only limited importance in minimising the impact of bioenergy crop cultivation on food production. Since the majority of agricultural land will remain in food production, it could be argued that the best way to most effectively utilise the limited area of land is to increase and optimise yields of food crops thereby potentially allowing greater areas for the production of bioenergy crops rather than focussing on increasing yields of crops which will only ever occupy a small proportion of land. The UK may need to increase wheat production in the future to meet global wheat demands as the climate changes as, in the short term at least, the UK may be able to increase wheat production whereas the output from some other regions is likely to reduce.


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5 Socio-economics 5.1 Summary of current issues The social-economic aspects of bioenergy involve:  

the impacts from adoption, e.g. to employment, inequality, or food security; and the social barriers to adoption, e.g. from lack of knowledge or behavioural barriers.

There have been suggestions that a push for environmental sustainability could undermine rural development and increase poverty in some areas. There is a need to understand social barriers, as these may reduce adoption and lead to the levels of uptake not meeting expectations, and a failure to achieve policy targets or generate anticipated benefits. Consideration is given to bioenergy feedstock production occurring in the UK and major international markets, i.e. Indonesian palm oil, US corn ethanol, and sugar cane from Brazil and Guatemala. The following section briefly outlines the socio-economic aspects of energy crops. The economic impacts are examined in more detail in the theme exploring the current state of the bioenergy market. A summary of evidence reviewed for the socio-economics chapter is available as Appendix 7 to this report.

5.1.1 Social impacts Positive and negative social impacts can occur for both UK and imported bioenergy. The impacts can be in close geographical proximity or remote from the region of production and conversion. The conversion of land to bioenergy feedstock production, for example in the UK, has the potential to impact geographically distant regions, e.g. through global food markets and in-direct land use change. The interconnectivity of geographic regions, with regard to bioenergy, means the wider social impacts should to be considered, regardless of where production occurs. Employment One of the drivers for bioenergy is the opportunity it presents for rural development, both in developed and developing countries. The production of feedstock and its conversion, either into biofuels, heat or power, has the ability to contribute to rural employment and income creation. Jobs can be supported directly in the bioenergy supply chain, in feedstock production, transportation or conversion, and also indirectly in the wider economy. However the bioenergy sector will potentially displace previous activities, for example a previous land use, and the net impact needs to be considered. Incomes and working conditions Diversified farm income from bioenergy feedstock production has the ability to improve farm viability, farm business income stability and possibly increased farmers’ incomes. Improved farm revenue also provides the prospect of potentially higher salaries for farm workers. The nature of new development undertaken will have varying social implications depending on whether the jobs created have better or poorer working conditions, for example, casual labour that can be vulnerable to low pay and high job insecurity. The nature of income effects and quality of employment will depend on the specific situations, governance structures, local legislative frameworks (e.g. employment rights) and the activities involved.


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Inequality Any benefits and losses accruing from bioenergy may not be distributed evenly. In some situations, the economic livelihood of a few may be increased, while others are negatively impacted, potentially creating or widening inequality. This is a concern in some countries where there is already large inequalities in terms of rights, assets and power. In the UK there may be distributional impacts, especially if government subsidies are involved. Land use rights Where land use change occurs, particularly in developing countries, there can be negative impacts, potentially creating economic, welfare or cultural damage. This can occur through the loss of the previous land use, or from the loss of land access, either to existing landowners or customary land users. Food security Food security is generally considered as having access to sufficient, safe and nutritious food, and therefore encompasses the affordability as well as the availability of food. Bioenergy, and in particular biofuels, have been suggested to be responsible for reducing food security, primarily by leading to higher food prices and increased food price volatility, by displacing or directly using food crops. Human wellbeing can be significantly reduced in some counties and across some income groups by higher food prices or reduced availability of produce, which may also be caused due to changing agricultural practices. Health There may be health implications, either from working directly in the biofuel supply chain, e.g. from poor practices when working with agro-chemicals, or from environmental impacts caused by bioenergy production.

5.1.2 Social barriers Social barriers to the adoption of bioenergy occur in feedstock production or conversion, and are relevant to UK and imported bioenergy. Public acceptability There may be changes in cropping patterns, including uptake of locally novel crops, or the construction of facilities to convert or process the feedstock. The location and scale of such developments may be constrained by public perceptions. Behavioural and attitudinal barriers Farmers or land managers / owners may be reluctant to change historic agricultural practices and adopt novel and locally untried crops, for example resulting from a high perception of risk associated with these crops. Such resistance to change may result in time lags in the adoption of otherwise economically rational activities. Knowledge or education There may be knowledge or educational barriers that act to stop certain groups being able or willing to adopt (or support) bioenergy feedstock production.

5.2 Summary of information in the literature The evidence on social impacts and barriers, in the literature reviewed, is divided into UK and internationally related. However, due to the links created by global commodity markets, and the potential for in-direct land use change, the location of impacts may not just occur in geographic proximity to the feedstock production, e.g. UK production may cause impacts in another countries. Where no evidence has been found the section is omitted, the subsequent evidence gaps section provides more details on these areas.


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5.2.1 Social Impacts Employment UK: NNFCC estimate that there would be 35-50,000 jobs supported in the UK bioenergy sector, excluding biofuels, to meet the bioenergy projections in DECC’s Renewable Roadmap (25-41 TWh of electricity and 33-44 TWh of heat). These jobs were primarily in plant construction (47%) and operation (33%), while UK feedstock production only accounted for 14% of job creation. This does not take into account any displacement of jobs from previous agricultural activities. Although the transport and conversion of UK energy crops are likely to create employment and diversify rural economies, the feedstock production is likely to be associated with lower agricultural employment in comparison to arable cultivation. The balance between jobs supported and job displacement varies based on local factors, the scale of development, and the level of previously unused production capacity (i.e. the capacity to produce an agricultural commodity that is currently not being used, e.g. a field left fallow or unplanted, or less intensively managed). International: It has been estimated that each US corn ethanol plant (for plants that produce 60 Million Gallons per Year) supports 54 direct and 210 indirect jobs. As these plants are frequently located in remote areas they can support fragile local economies, helping to address rural depopulation. The use of existing over-production or unused production capacity is cited as having occurred in the Brazilian, Malaysian and Indonesian biofuels sector, based on the legacy from their existing sugar cane or palm oil sectors. It is estimated that up to 4.5 million Indonesians directly or in-directly depend on the palm oil industry, although only around 2% of production in 2010 was used for biofuels. Incomes and working conditions International: Positive livelihood benefits have been seen for Indonesian palm oil employees. However, survey work there has also suggested that the casual labour created on plantations does not meet the expectations of satisfactory working condition, e.g. there are unsafe practices, low pay and a lack of the freedom to join a union or collectively bargain. There has been some suggestion that sugarcane cutters in Brazil do receive above minimum wage, although not sufficient to escape the poverty level. Inequality UK and International: One common finding was that many outcomes, including inequality, depended on the scale of production system used. There is evidence that in some situations a more decentralised approach, using smaller scale production or process facilities, generates greater social benefits with a more even distribution of income. However, larger plantations benefit from economies of scale, while smaller producers face greater barriers due to low market power and lack of knowledge. Land use rights International: Land ownership may also be affected, particularly by large plantations, such that the well-being of poorer communities may be adversely impacted. The groups most negatively impacted by Indonesian palm oil production have been former landowners and customary land users as a result of land use change. An example given was indigenous tribes being forced by palm oil companies to give up land, resulting in areas of cultural significance such as ancestral graves being destroyed. This issue has given rise to the call to strengthen customary land rights. Food security UK: The impact on food security is perhaps less acute in the UK, than in some other regions, due to the relatively low average percentage of incomes spent on food. Nonetheless, there is


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evidence that higher prices cause some switching from fresh food to less healthy processed food in the UK. International: As many developing countries are net food importers, the high food prices and low supply in 2007/8 created food insecurity which is estimated to have caused an additional 200 million people to have insufficient food. Shortly after this event, a number of studies were published linking the price increases to biofuel subsidies in developed countries. It was suggested that in Sub-Saharan Africa calorie intake will be reduced by 11% by 2020, due to food-biofuel competition, with oilseed prices 76% higher by that date. UK and International: Despite continued increases in bioenergy after 2008, prices returned to more sustainable levels, suggesting significant contribution from other factors, such as harvest failures, globalised trade and speculation. The debate on the level of impact of food versus fuel continues, however where there is under-utilised agricultural capacity, or increases in agricultural productivity make land available, such conflicts can be minimised. Also, there may be potential production systems where food and bioenergy can be produced in a complementary, rather the conflicting, manner. The land use change theme discusses the food versus fuel issue in greater detail. Health International: There are several claims that the health of plantation workers suffers due to bad practice when spraying agro-chemicals or from accidents with plantation equipment, both in Indonesia for palm oil production and on Brazilian sugar cane plantations. Also, there are claims that agro-chemical and palm oil mill effluents contaminate the drinking water of some rural communities. In Brazil respiratory related health problem increase during the sugar cane burning season, with two to three times more child hospital admissions during the period. However, care must be taken to consider the health implications from the counterfactual employment opportunities or land uses, as this has not yet been done.

5.2.2 Barriers Public perception UK and International: Processing facilities to convert feedstock are required for all types of bioenergy. As these are usually industrial processes and often substantial in scale, there are limited areas that are likely to be publically acceptable for such developments, this creates a constraint on bioenergy development. It is not clear from the research how significant a constraint it places on the market or how it differentially impacts alterative feedstock or conversion technologies. Behavioural and attitudinal barriers UK: Direct elicitation of UK farmers’ opinion on growing energy crops found a reluctance to change existing practices. There is also evidence of a ‘follow the leader’ attitude, where observations of neighbouring farmers decision and the outcomes of these influence preferences and behaviour. Part of this is the higher perception of risk associated with new and locally untested production techniques or crops. Communication between individual farmers is therefore important in uptake, resulting in the diffusion of knowledge and innovation within a geographic area. Results modelling this process for energy crops show long time lags (around 20 years), similar to previous novel crop uptake. Inclusion of behaviour barriers also substantially reduced the eventual level of uptake, as economies of scale could not be reached. The low uptake of energy crops in the UK, despite the availability of subsidies and evidence of potential economic benefits, also supports the importance of these barriers. Knowledge or education UK: Knowledge barriers have been identified, relating both to the awareness of available subsidies and the correct establishment and management practices for perennial energy


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crops. For example, a lack of awareness amongst farmers has been suggested as one reason behind the low uptake of the Energy Crop Scheme 2. International: A lack of local knowledge may act as a barrier to achieving the small-scale production of palm oil and sugar cane associated with more advantageous outcomes such as lower inequality and greater rural development. Similarly, local customary land users and former landowners displaced by plantations may not be able to benefit from the employment opportunities created, as they do not have the required knowledge or skills.

5.3 Confidence in the results As indicated by the number of articles that refer to it, there is a widespread acknowledgement that social issues, as well as environmental and economic considerations, are factors in the adoption of bioenergy. A comprehensive and usable definition of social sustainability is more challenging. Many articles refer briefly to social issues or sustainability, without defining or quantifying them. Where more detailed investigations into the social impacts have been conducted, it has been in relation to food crops used for biofuels. The social barriers to adoption are less commonly explicitly addressed, although there has been some work on the barriers to adoption of UK grown dedicated energy crops, i.e. energy grasses and short-rotation coppice. Even in these areas, confidence cannot be considered high due to the relative lack of evidence in comparison to other aspect of bioenergy, and the conflicting messages, for example the impact on food prices. There is no evidence for the social impacts or barriers to the adoption of tallow, poultry litter, used cooking oil or straw. The confidence level by sub-theme is presented in Table 5-1 below. Table 5-1: Confidence in social impacts and barriers Imported biofuels

UK food crops used for biofuels

UK dedicated energy crops

Employment

Medium

Low

Medium

Incomes and working conditions

Medium

Low

Low

Inequality

Low

Low

Low

Land use rights

Medium

Low

Low

Food security

Medium

Medium

Low

Health

Low

Low

Low

Public perception

Low

Low

Low

Behavioural and attitudinal barriers

Low

Low

Medium

Knowledge or education

Medium

Low

Medium

Sub-theme Impacts

Barriers

5.4 Trends in the information The debate on food security impacts from biofuels has moved steadily since 2008, initially there was a high level of concern over the social impacts of the potential food versus fuel conflict, however, a range of other factors are now believed to be involved. With conflicting evidence, the level of impact from bioenergy on food security, both in the past and into future, is less clear.


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The significant impact of social and behavioural factors as barriers to the uptake of dedicated bioenergy crops is becoming clearer.

5.5 Evidence gaps 5.5.1 Described in the literature The net contribution to employment, including the impact of displacement of the previous land use, is not well understood for either imported or UK produced feedstock. There is an on-going uncertainty and debate as to whether or to what extent bioenergy contributes to food price increases and insecurity. The opportunity cost for bioenergy subsidy policies needs to be considered. The funding could have been used to support other measures, such as direct investment in rural development. There have been some conflicting results where this has been investigated, for example US biofuel subsides.

5.5.2 Gaps not described in the literature The social impact of UK produced bioenergy feedstock is not well researched or understood. Improvements in agricultural practices, population and lifestyle changes, lignocellulosic biofuels, and climate change all have the potential to change the land required for food and bioenergy production. There is insufficient evidence on how these factors will interact over time on the ability to meet both food and bioenergy demands in a socially sustainably manner.

5.6 Suggestions for further research 5.6.1 Described in the literature Research to quantify the net impact, including displaced activities, on employment, income and rural development from the adoption of alternative bioenergy technologies and scales. Include social adoption barriers into estimates and rates of bioenergy uptake. Undertake research to understand the impact and cost-effectiveness of potential mechanisms could be used to reduce these barriers.

5.6.2 Further suggestions Research is required into the synergies and trade-offs between the economic, social and environmental objectives. The social, economic and environmental aspects of the systems are highly coupled, making a good understanding of any aspect in isolation impossible. The potential benefits and dis-benefits of the adoption of bioenergy at scale require that we attempt to understand these interactions more fully, and to suggest ways that net societal benefits can be maximised.


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6 Greenhouse-gas mitigation potential 6.1 Summary of current issues Bioenergy could in principle be carbon neutral when used for heat power and transport, in that is its use does not produce a net increase of emissions because the amount of carbon dioxide (CO2) released on combustion equals the amount originally removed from the atmosphere during plant growth. In practice, however, bioenergy is not carbon neutral as emissions of the GHG, CO2, methane (CH4) and nitrous oxide (N2O) are produced across the entire supply chain from the planting of the crop, through to its fertilisation, harvesting, processing and transportation. These ‘life cycle’ emissions can be accounted for by estimating fuel, energy use and inputs at each stage of the supply and processing chain. In addition it is also necessary to account for:   

The benefits of any co-products (e.g. rape meal) produced when processing Emissions from land use change (LUC) – both direct (DLUC) and indirect (ILUC) Changes in carbon sequestration.

Accurate assessment of the GHG emissions from bioenergy is important, because one of the key drivers for bioenergy use is the potential role in decarbonising the economy. Different studies often reach different conclusions about the level of GHG savings that bioenergy can achieve because of: 1. Different assumptions about the supply chain, methods of cultivation, fuels used for processing, inputs etc., mainly reflecting the variability that exists 2. Different system boundaries, e.g. whether emissions associated with the production of agricultural machinery are included 3. Methodological differences in the ‘accounting procedure’ e.g. in how co-products are treated 4. Whether emissions from LUC are included and how these are estimated – particularly for indirect land use change 5. Different assumptions about the ‘counterfactual’/reference’ fossil fuel system that biomass emissions are compared to. The Renewable Energy Directive sets minimum GHG emissions savings that biofuels must meet and sets out a calculation methodology that specifies many of these aspects. The minimum GHG-emissions saving compared to fossil fuels is currently 35 %, rising to 50% from 2017 and from 2018 it must be 60% for new installations. In the UK, the methodology has been incorporated into the Department for Transport's Carbon Calculator for biofuels and bioliquids16. Ofgem has a similar carbon calculator for biomass used for heat and power production, which is also based on the methodology set out in the EU Renewable Energy Directive (RED)17. A summary of evidence reviewed for the greenhouse-gas mitigation potential chapter is available as Appendix 8 to this report.

16

https://www.gov.uk/government/publications/biofuels-carbon-calculator See: https://www.ofgem.gov.uk/publications-and-updates/uk-bioliquid-carbon-calculator and https://www.ofgem.gov.uk/publications-andupdates/uk-solid-and-gaseous-biomass-carbon-calculator 17


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6.2 Summary of information in the literature Emissions associated with cultivation stages of the supply chain Emissions from cultivation typically arise from the use of diesel powered farm machinery, emissions associated with the manufacture of inputs such as fertiliser and other agrochemicals and N2O emissions from application of fertiliser to soil (Figure 6-1). For the oil and sugar/starch crops used for biofuels, cultivation emissions are dominated by emissions associated with the manufacture of fertilisers and their application to soils. Emissions are higher for the annual crops, oil seed rape (OSR) and wheat than the perennial crops oil palm and sugar cane, due to their higher fertilisation requirements. Sugar beet has lower cultivation emissions then OSR and wheat due to the incorporation of nitrogen rich sugar beet tops into the soil which reduces fertiliser requirements. N2O emissions from soil following fertiliser application are the result of the biological processes of nitrification and denitrification and are influenced by a number of factors, including soil type, moisture content and temperature so that emissions in response to N applications from fertiliser can vary significantly at the local scale. Figure 6-1 Typical emissions from cultivation for biofuels feedstocks (g CO2e/MJ of biofuel produced)

Source: CCC, 2011

Dedicated energy crops, such as Miscanthus and SRC have very low fertiliser requirements, most of which are associated with establishment of the plant in the first year and have much lower cultivation emissions than annual crops (Figure 6-2). Emissions from energy grasses are higher due to higher fertiliser application rates, but are still lower than for annual crops used for biofuels. There is less assessment of the energy crops which are being more recently considered for the UK (switchgrass and reed canary grass).


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Figure 6-2 Typical emissions from cultivation for woody energy crops (g CO2e/MJ of energy in crop)

g CO2e0/ MJ energy in fuel

1.2

1.0 0.8

Fuel use on farm Planting material

0.6

Pesticides Fertilisers

0.4

N2O emissions 0.2

0.0 SRC

Miscanthus

Source: Derived from Ofgem solid and gaseous biomass calculator

For agricultural residues such as straw, some studies treat it as a co-product which should accrue some of the GHG emissions associated with production of the whole crop (see coproducts below). Other studies treat it as residue or waste product, which does not have any GHG emissions associated with its production, only its collection, processing and transport. This is the approach taken in the RED. Options for reducing emissions from annual crop production are to reduce fertiliser requirement while maintaining yield through crop development and breeding, employing better management practices to minimise the release of N2O following fertiliser application, and using good crop protection regimes. Reducing GHG emissions associated with fertiliser manufacture through energy efficiency improvements and abatement of N2O emissions from the manufacturing process can also reduce emissions. For dedicated energy crops, ensuring that planting density, fertiliser application and harvesting frequency are optimised based on site specific conditions, can help to minimise emissions. One current area of research is whether the addition of biochar to Miscanthus (produced when biomass is pyrolysed) can reduce net CO2 emissions from the soil. Treatment of co-products Co-products can arise from the cultivation and harvesting of biofuels crops (e.g. straw from wheat production) or during their processing into biofuels (e.g. rape meal from oil seed crushing, or Dried Distillers Grain with Solubles (DDGS) produced when processing wheat for bioethanol). As these co-products can have valuable uses (e.g. as animal feed) it is necessary to allow for this in the GHG emissions calculation. Different approaches to this can lead to significantly different results. The main methods are: 



Consequential Life Cycle Analysis (LCA), (appropriate for considering the policy or wider impact of bioenergy production), normal practice is to expand the analysis to consider the consequences associated with production of the co-product. For example for DDGS used as animal feed, the GHG emissions avoided for the animal feed no longer needing to be produced are included. Attributional LCAs, (appropriate for considering the impact of a particular supply chain) allocation is commonly used. In this emissions are allocated between the main product and the co-products according to mass, energy or economic relationships such as price. Calculation of GHG emissions for the purposes of the RED is done by allocating by energy content.


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Different methods of treating co-products can lead to significant differences in estimates of the savings that biofuels can achieve, as shown below (Figure 6-3). Figure 6-3: Influence of methdology for treating co-products on emissions savings from biofuels

Source: CCC, 2011

Land-use change emissions All bioenergy crops can cause LUC either directly by being grown on previously uncultivated land, or indirectly by displacing food/feed crops from agricultural land leading to additional land being brought into cultivation elsewhere. DLUC can be measured but indirect ILUC must be modelled18. GHG emissions occur if conversion of the land releases carbon stored in the soil and existing vegetation. The magnitude of the emissions depends on the current use of the land, but also on the longer term impact of bioenergy crops on soil carbon, for which there are relatively few long term studies. A final consideration is the land-use reversion which will occur at the end of the economic lifetime of perennial crops, and there is little data on the GHG implications of this. In general, annual cropland conversion to perennial crops results in increased carbon stocks, while carbon is lost through conversion of perennial crops or grasslands to annual crops. Conversion of managed grassland to perennial energy crops appears to give no change in soil carbon, while conversion of semi-natural grassland to perennial energy crops gives a decrease in carbon stocks. Estimates of emissions from direct land use change are often based on estimates of emissions from LUC developed for use in national GHG emissions, and development of data to allow estimates at a finer spatial resolution that reflects regional and local conditions would improve the accuracy of estimates. The ongoing ELUM (Ecosystem Land Use Modelling and Soil C Flux Trial) research project is looking in more detail at LUC in relation to SRC-Willow, Miscanthus, SRC, and OSR, sugar beet and winter wheat and is carrying out measurements on trial plots to establish changes in soil carbon and improve the quality of data in this area. The RED requires the calculation of emissions from direct LUC and it is currently being considered whether an ILUC emissions factor should also be applied19. Due to the complexity of calculating indirect land use change emissions, there is substantial uncertainty over ILUC emissions and estimates from studies have varied substantially by study and depending on crop from about 20 to 100 g CO2/MJ. Results from modelling carried out for the European Commission are shown below (Table 6-4). In common with most other 18 19

See Land Use Change theme See Land Use theme


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studies, they show higher ILUC emissions from biodiesel feedstocks than for ethanol feedstocks. This led to the proposed inclusion of ILUC factors of 12 g CO2e/MJ for cereal and other starch rich crops, 13 g CO2e/MJ for sugars and 55 g CO2/MJ for oil crops. On the basis of these values, including the impact of ILUC would mean that emissions from biodiesel produced from OSR and soybean would be higher than those from conventional diesel. Figure 6-4 Estimated indirect land-use change emissions (g CO2 e/MJ) including uncertainty estimates

Note: the bars indicate 1st and 99th percentile, while the boxes are 25th and 75th percentiles Source: European Commission, 2012

Overall emissions and mitigation potential The overall savings offered by biofuels depends also on the emissions from other stages. For biofuels, the other key stage is the processing of feedstocks into the fuels. For biomass used for heat and power, harvesting, transport, drying, and processing of the fuel e.g. chipping and/or pelleting all contribute. For biofuels, particularly ethanol production which has substantial energy requirements, emissions can be reduced by using a low carbon fuel such as gas, or biomass, and using combined heat and power (CHP) plant to increase the efficiency with which process energy is provided. There is substantial interest in biorefinery concepts, where as many by and co-products are utilised (either within or without the production process) to give the most efficient use of the biomass resource and reduce overall emissions. In the case of solid biofuel, pelleting while helping to improve the energy density and ease of handling of the fuel can increase emissions substantially due to the need to reduce the moisture content of the fuel before it can be pelleted. These emissions can be reduced by using a proportion of the biomass to provide the heat required for drying. For solid heat and power the efficiency with which the biomass is combusted also influences emissions per unit of energy delivered, and higher savings may be achieved by co-firing biomass in large power plant with higher efficiencies. Another option for reducing emissions from biomass is to apply


31


carbon capture and storage to biomass power stations; this can result in negative overall emissions, and some argue that because of the possibility that this offers to reduce emissions, biomass should be preferentially used in large power plant where CCS could be applied. A potential additional source of GHG emissions from biomass combustion is black carbon. This is not a GHG but has been identified as an important short lived radiative forcing agent which is potentially contributing significantly to climate change. In the developed world the main man made sources are transport vehicle exhausts (diesel engines) and residential solid fuel combustion. For biomass used for heat and power, the main appliances of concern are room heaters, which may be batch fed and manually controlled making it difficult to control combustion processes and thus black carbon emissions. Automatically fuelled and controlled combustion sources (typically boilers and larger installations) general have higher combustion efficiencies and are often fitted with particulate abatement technologies which reduce emissions of black carbon. Typical emissions from a number of biofuels are shown below based on typical values (Figure 6-5). After allowing for ILUC, crop based biodiesel routes do not typically offer emissions savings, while bioethanol offers savings of about 45% to 60%. Biodiesel produced from UCO and tallow also offers substantial savings, of almost 90%. Figure 6-5: Typical emissions from biofuels inlcuding ILUC emissions (g CO2 e/MJ)

Source: CCC, 2011 Estimates of emissions from the use of energy crops for heat and power are available from the Ofgem calculator. Values for electricity generation from SRC and Miscanthus20 (using the default values in the calculator) are shown in Figure 6-6; these assume no direct or indirect LUC. For comparison, emissions associated with marginal electricity generation (assumed to be gas fired CCGT) are 104 g CO2/e/MJ, so use of chips or pellets produced using biomass to supply heat for drying deliver substantial savings (76 to 91%). Using gas to dry the fuel before pelleting it can increase emissions substantially and reduce savings (to 36%)21.

20

Based on default values in the calculator and assuming 30% efficiency for electricity generation Biomass electricity generation under the RO must achieve a saving of 60%, but this is based on the value for electricity generation put forward by the European commission of 198 g CO2 e. Using this comparator a saving of 67% would be achieved for pellets from SRC produced using gas for drying. 21


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Little work has been done on assessing ILUC and associated emissions from energy crops such as Miscanthus and SRC, although one theoretical study (for Denmark), which assumed that Miscanthus and SRC production replaced the Danish marginal crop of spring barley found that the magnitude of the ILUC emissions was large and negated savings for most types of electricity production from the crops. Figure 6-6: Typical emissions from biomass electricity production (g CO2 e/MJ)

g CO2e/MJ electricity

70 60

50 40 30 20 10 0 chips

pellets (biomass drying)

pellets (gas for drying)

chips

Miscanthus

pellets (biomass drying)

pellets (gas for drying)

SRC

Source: Derived from Ofgem solid and gaseous biomass calculator

Overall, it is considered that bioenergy could make a substantial contribution to primary energy needs in the future, and that it has an important role to play in contributing to carbon reductions. Costs of bioenergy as a mitigation option The cost-effectiveness of bioenergy as a GHG mitigation option was calculated for the bioenergy strategy. For SRC, it was estimated to be about £200/t CO2 (in 2020) for electricity production in large biomass plant, use for heat production in industry was more cost-effective (less than £100/t CO2) when the fuels replaced were not gas, but slightly less cost-effective than power production if heating would otherwise be provided by gas. Use of SRC for domestic heat was less cost-effective than for industrial heat. In the transport sector, DfT calculated that the cost-effectiveness of using bioethanol was less than £100/t CO2 even if ILUC impacts are included, whereas inclusion of ILUC effects for crop based biodiesel gave an extremely high price for carbon mitigation. Values are however uncertain, reflecting not just the uncertainties in lifecycle emissions discussed above, but also uncertainties in the future costs of biomass and biofuels, and other studies have suggested values quite divergent from those in the bioenergy strategy.

6.3 Confidence in the results Table 6-1: Confidence in evidence of the impact on GHG emissions of biomass feedstocks Cultivation emissions

Use of coproducts

Direct and indirect land-use change

Overall Costemissions effectiveness and mitigation potential

Medium

Medium

Medium

Medium


Low

33


While there is considerable variation in estimates of GHG emissions from the bioenergy crops considered, the reasons for the variations are well studied and understood. Some variation is due to differences in methodological approaches and some is due to real variability in the supply chain for bioenergy. Estimates of the cost-effectiveness of bioenergy require combining estimates of emissions from bioenergy supply chains, choice of reference comparison system and estimates of cost of biomass supply and conversion, so levels of uncertainty are higher. Less information is available on this aspect.

6.4 Trends in the information There is a good understanding of the key factors which affect GHG emissions from biofuels, and the emphasis now is on improved understanding and data for key aspects i.e. yield, N2O emissions in cultivation, changes in soil carbon and direct and indirect land use change. There appears to have been more emphasis on analysis of biofuels, probably driven by the targets and mandatory reporting of GHG emissions required by the RED. There has been a trend for estimates of the magnitude of ILUC impacts to decrease over the period from 2007 to present. However, ILUC is still a significant contributor to GHG emissions for some biofuels and uncertainty in estimates is still large.

6.5 Evidence gaps 6.5.1 Described in the literature Better information on LUC and on soil carbon, including long term measurements of land under energy crops, and on changes at point of grubbing up. Continuation of the ELUM project is one possible way to provide this information. Assessment of potential ILUC and associated emissions from cultivation of perennial energy crops. Black carbon emissions from small scale biomass combustion.

6.5.2 Gaps not described in the literature Assessment of GHG emissions from reed canary grass and switchgrass in the UK.

6.6 Suggestions for further research 6.6.1 Described in the literature As described in 6.5.1.

6.6.2 Further suggestions Comprehensive data on cost effectiveness of bioenergy as a mitigation option


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7 Land-use change 7.1 Summary of current issues All bioenergy crops can cause land-use change (LUC), either directly by being grown on previously uncultivated land, or indirectly by displacing food/ feed crops from agricultural land leading to additional land being brought into cultivation elsewhere. Straw, chicken litter, tallow and wastes are assumed to be feedstocks that do not cause land use change. Governments promoting bioenergy in Europe and the USA recognise that LUC can reduce the carbon emissions savings benefits of bioenergy and may have other unintended environmental and social consequences. They are working to include management of land use change impacts in current legislation covering sustainability22. European bioenergy sustainability legislation currently includes provision for direct land-use change (DLUC), and the UK is involved in negotiations at the EU level to find a policy solution which mitigates the impact of indirect land-use change (ILUC). USA schemes include both DLUC and ILUC contributions in GHG emissions estimates for production of ethanol from corn. DLUC can be measured directly and there is good evidence of the carbon stock impacts of changing from a range of land types to bioenergy cultivation. It is recognised that high biodiversity and high carbon stock land should be preserved and conversion to bioenergy production is prohibited under current legislation. The challenge is to ensure that this is respected in all areas where bioenergy crops are produced. Indirect land use change cannot be measured directly, and is difficult to assess with confidence. A number of approaches ranging from simple spreadsheet modelling to complex global economic modelling have been employed over the past six years to try to quantify ILUC. A wide range of results have been obtained but most confirm that ILUC can be significant23, although recent modelling tends to give lower estimates than early modelling. A number of approaches are suggested in the literature reviewed to minimise indirect land use change. In summary these are:      

Constrain production of bioenergy from food/ feed crops Support production of bioenergy from low ILUC risk feedstocks (those not requiring dedicated land for their production) Include estimates of GHG emissions from ILUC in GHG emissions estimates for bioenergy Account for direct LUC for all land uses and globally, so that there is no ILUC. Promote investment to sustainably increase agricultural land productivity (increased yields, double cropping, integrated farming). Utilise marginal land for bioenergy e.g. low productivity land, degraded land or abandoned agricultural land.

22

In the EU, renewable energy policy to 2020 is set by the Renewable Energy Directive (RED). RED contains mandatory provisions for the sustainable production of biofuels and bioliquids, and the EC has also published advice to Member States on how to introduce sustainability provisions for production of solid and gaseous biomass feedstocks for heat and electricity production at the National level. The Fuel Quality Directive (FQD) shares the same sustainability requirements for bioenergy. In the UK the RED and FQD are implemented via the RTFO, the Motor Fuel GHG Emissions Reporting Regulations, RO, FIT, RHI, CfD. The RTFO and RO have mandatory sustainability requirements for biofuels and bioliquids consistent with requirements of RED/ FQD. The UK has introduced sustainability reporting for solid biomass for heat and power and has plans to introduce sustainability requirements and make compliance with these mandatory. The USA has a mandate for biofuels, US-RFS2, which reaches 36 billion US gallons by 2022. California has the Low Carbon Fuel Standard (CALCFS) with the goal of a 10% reduction in transport fuel GHG emission intensity by 2020. 23 See GHG theme for further details.


35


It is likely that a combination of these approaches will be the most effective way to minimise ILUC. Recent evidence concludes that the current level of biofuel production has had only a minor impact on food price and food availability. A summary of evidence reviewed for the land use change chapter is available as Appendix 9 to this report.

7.2 Summary of information in the literature This is organised by sub-theme. The majority of evidence discusses the impacts of biofuels crops on a global basis. Where there is evidence on individual crops this is highlighted.

7.2.1 Direct land-use change DLUC occurs when land that was previously used for another purpose is converted to bioenergy feedstock production. DLUC can be measured, and may have positive or negative impacts. The impact of DLUC depends on:    

The previous land use, in particular, the above and below ground carbon stock in the vegetation The bioenergy feedstock and how it is managed The scale of the feedstock production Environmental factors including the climatic region where the land use change occurs and soil type.

The area of DLUC for a given energy production will strongly depend on the yield of the bioenergy feedstock and the conversion efficiency from feedstock to final fuel. Land use opportunities will vary regionally and consideration of suitable bioenergy crops at regional level would benefit land use efficiency. Major schemes incentivising bioenergy production in the EU and USA aim to prevent conversion of high biodiversity and high carbon stock land to bioenergy production, by means of including sustainability requirements in legislation. The EU also has a requirement for monitoring and certification of sustainable production. The effectiveness of schemes to ensure sustainable production depends on the availability of information on the full range of impacts and throughout all stages of production. This is essential to verify compliance with confidence but must be achievable at reasonable cost. Non-governmental organisations (NGOs) have supported and helped the development of a number of sustainability schemes. However, they have also questioned both the scope and effectiveness of some of the current sustainability schemes, particularly those that cover only the criteria required for RED/FQD (Renewable Energy Directive/Fuel Quality Directive). . The impact of DLUC on carbon stock, biodiversity and water use is detailed in the relevant themes. To date impacts have only been quantified for change in carbon stock24. Marginal land has been suggested as suitable for production of lignocellulosic bioenergy crops such as SRC, Miscanthus and switchgrass. However, definition of marginal land is unclear, as it may cover low productivity land, degraded or abandoned land. Depending on the type of land, lignocellulosic crops can offer an opportunity to improve the land, but yields will be low and production may require additional support to be cost effective. In addition there may be issues with existing informal land use rights.

24

See GHG emissions theme.


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7.2.2 Indirect land-use change Indirect land-use change (ILUC) may occur when bioenergy feedstock is produced on land that was previously used to provide food, feed or fibre. Assuming the demand for the food, feed or fibre still exists, it will have to be met from another source. One option is to use previously uncultivated land to meet the demand, which leads to indirect land use change. ILUC was first recognised as a threat to the sustainability of bioenergy production in 2007, and substantial work has been done since then in both Europe and the USA to quantify the ILUC risk of bioenergy production. The magnitude of ILUC for a given bioenergy crop depends on a number of factors     

Which replacement products may be used instead of the displaced crop (substitutability) Where any replacement products are grown (what land is converted) Yield/ management of replacement products (how much land/ impacts) Possibility to increase yields of bioenergy feedstock/ original product and so increase land use efficiency (intensification/ integration) Possibility to use co-products from bioenergy production to substitute for original product.

ILUC cannot be measured directly. Estimating ILUC therefore depends on modelling efforts. These can be grouped into: 





Those that use historic data on land use change and crop production to estimate the amount and type of land that would be converted for additional crop production for bioenergy on an area for area basis. These tend to give the highest ILUC impacts. A spreadsheet based approach to the actual land area required to replace the energy crops which attempts to identify the type of land that will be converted, the impacts of higher levels of inputs, higher yields, the production of co-products along with biofuels and the fact that the higher commodity prices will have a dampening effect on other demand for the agricultural commodities. These highlight the impact or various factors but outputs are very subject to the input assumptions. Those that use economic modelling tools such as Partial Equilibrium models (PE) and Computable General Equilibrium models (CGE) to predict LUC that can be attributed to bioenergy, given a range of assumptions about future demand for food, feed and bioenergy. These encompass the widest range of interactions affecting ILUC, including the impact of co-product utilisation, but are subject to a number of uncertain assumptions.

A wide range of estimates of the type and amount of ILUC resulting from production of bioenergy crops, and the related values for the GHG emissions impacts of ILUC for individual crops (ILUC factors) have been proposed in the last 6 years as a result of this modelling, and these are reviewed in the GHG theme. Although there remains debate on these values, there is agreement that ILUC could be significant and should be taken into account in consideration of the sustainability of bioenergy production. A number of approaches have been suggested for managing ILUC impacts within schemes to promote bioenergy. These are summarised in Table 7-1 below.


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Table 7-1: Strengths and weaknesses of the approaches to managing ILUC Approach

Strengths

Weaknesses

Constrain production from food crops

Straightforward to implement

Threatens existing biofuels investments. Increases costs.

Support production from low Encourages utilisation of wastes ILUC feedstocks such as wastes and straw

Competition for finite resources Constrains bioenergy potential Risk of fraud.

Support low ILUC approaches such as integrated farming or double cropping or use of marginal land

Encourages more efficient use of Setting baseline for integrated land and more crop diversity. production Opportunity to improve productivity of marginal land.

Cost of production on marginal land and land tenure issues. Management of impacts on water, soil and biodiversity. Needs to be evaluated at regional or project level.

Introduce ILUC factors

Can be combined with existing GHG emissions methodologies Easy to see impact on overall GHG emissions savings.

Wide range of estimates for ILUC factors- very dependent on assumptions. Inherent uncertainties in methodologies. Only addresses carbon stock issues.

Expand scope to consider land use change from all causes

Can be measured.

Requires co-operation across all land using industries.

Investment in increased crop productivity

Reduces land requirements.

Setting productivity baseline.

Wider positive impact on agricultural incomes.

Attributing benefit to bioenergy. Managing impacts on water, biodiversity and production GHG emissions.

There is currently no consensus on the best way to minimise ILUC, or how best to include ILUC in legislation. It is likely that a combination of the above approaches will give the best outcome. Although the majority of work has focussed on the ILUC effects of food crops used for biofuels, the issues and methodology are equally applicable for production of lignocellulosic crops on land previously used for food crops.

7.2.3 Competition for land use between food/ feed and energy crops There is serious concern that large scale use of food crops for biofuels can affect both the price and availability of food. Research in 2008 supported this concern by suggesting that biofuels were a major contributor to the food price spike of 2006-2008. However, more recent research shows that the food price spike was caused by a number of factors and biofuels had only a minor influence. Major factors leading to local hunger were identified to be crop yield, food waste, poor infrastructure, poorly functioning local markets and conflicts rather than reduced exports from developed countries.


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Increased use of crops for biofuels could have more influence on the food markets. However, there is no agreement that these impacts will necessarily be negative and lead to reduced availability and higher prices. Depending on how biofuels are implemented positive effects could include encouraging a less volatile market and driving improved agricultural practices. Lignocellulosic crops can also affect food production by displacing agricultural crops. Use of marginal/ abandoned/ degraded land avoids displacement of food crops, but is only likely to be suitable for lignocellulosic crop production and has potential environmental and social impacts.

7.2.4 Voluntary sustainability assurance schemes The RED/ FQD require sustainable production of biofuels to be assured by means of monitoring and verification. EC maintains a list of Voluntary Sustainability Schemes approved for RED/ FQD. These are often of wider applicability than biofuels and cover a wider range of sustainability criteria than those required under RED/FQD. The implementation of schemes and verification of data has been criticised by NGOs. In particular they feel that some schemes are weak in the level of assurance provided. They also feel that the range of sustainability criteria required under RED need to be expanded before feedstock production can be considered sustainable in a wider context.

7.3 Confidence in the results The confidence ranking based on review of individual papers and agreement across papers (Table 7-2). Table 7-2: Confidence in evidence of the impact on land-use change of biomass feedstocks DLUC change

ILUC

Food v fuel

Other impacts – marginal land

High

Medium

Low

Low

The majority of evidence on LUC relates to biofuels in general. There is a small amount of evidence on individual crops that is normally related to an individual country or region. Evidence on lignocellulosic crops mainly relates to issues in utilising marginal land. There was no evidence on non- crop feedstocks.

7.4 Trends in the information There has been a trend for estimates of the magnitude of ILUC impacts to decrease over the period from 2007 to present. However, ILUC is still a significant contributor to GHG emissions for some biofuels and uncertainty in estimates is still large. Recent estimates of impacts of biofuels on food prices and food availability suggest lower impacts than those originally suggested in 2008, at current levels of production.

7.5 Evidence gaps 7.5.1 Described in the literature  

Methodology for proper consideration of uncertainty in ILUC assessments. More transparency in LUC modelling efforts to enable differences in outcomes to be better understood.


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7.5.2 Gaps not described in the literature Nothing further identified.

7.6 Suggestions for further research 7.6.1 Described in the literature 

Specific LUC estimates for crops grown in the UK

7.6.2 Further suggestions 

Flexibility for bioenergy mandates to allow temporary diversion into food markets. Mechanisms for bioenergy producers to manage this.


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8 Biodiversity Article 2 of the Convention on Biological Diversity (CBD) states that: "biological diversity means the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems".

8.1 Summary of current issues Many UK habitats prioritised for conservation25 encompass habitats of European importance26. Together, they support thousands of species; some of international significance, a few predominantly found here. In the past 50 years, there has been a substantial decline in the extent and/or condition of most of the UK’s semi-natural habitats and associated species’ loss, particularly as a result of intensification of use of land and resources (and other associated drivers of change). The UK National Ecosystem Assessment27 (2011) has identified that biodiversity continues to face a range of threats, including:   

Land use change and pollution, which are the major drivers of change across species groups. Climate change, with growing evidence of impacts across most species groups Non-native invasive species, although regarded as less important for most species.

The CBD’s global target to reduce significantly the rate of loss of biodiversity by 2010 was not achieved. The CBD’s Strategic Plan for Biodiversity for 2011-2028 includes targets to: at least halve and, where feasible, bring close to zero the rate of loss of natural habitats; establish a conservation target of 17% of terrestrial and inland water areas and 10% of marine and coastal areas; restore at least 15% of degraded areas. This plan provides the basis for Biodiversity 2020: A strategy for England’s wildlife and ecosystem services29 (2011) and the 2020 Challenge for Scotland's Biodiversity30 (2013); a strategy is also being reviewed and developed in Wales. The Lawton Review (2010)31 identified that “The essence of what needs to be done to enhance the resilience and coherence of England’s ecological network can be summarised in four words: more, bigger, better and joined”. This reflects a progressive shift in conservation thinking from a traditional site-centred, species-orientated, designation-focused approach to one that also considers the need for action at a landscape scale. There is increasing appreciation that this evolving approach demands integrated action that pays due heed to the fact that “A healthy, properly functioning natural environment is the foundation of sustained economic growth, prospering communities and personal wellbeing32”, as highlighted in the UK Government’s Natural Environment White Paper (2011). Production of agricultural biomass (i.e. current crops used for biofuels, purpose grown energy crops and agricultural residues) used for bioenergy in the UK has the potential to impact directly on biodiversity through positive or negative changes in:

25

http://jncc.defra.gov.uk/PDF/UKBAP_PriorityHabitatDesc-Rev2011.pdf http://jncc.defra.gov.uk/ProtectedSites/SACselection/SAC_habitats.asp 27 http://uknea.unep-wcmc.org/ 28 http://www.cbd.int/sp/ 29 https://www.gov.uk/government/publications/biodiversity-2020-a-strategy-for-england-s-wildlife-and-ecosystem-services 30 http://www.scotland.gov.uk/Publications/2013/06/5538 31 http://archive.defra.gov.uk/environment/biodiversity/documents/201009space-for-nature.pdf 32 https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/228842/8082.pdf 26


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     

Species; abundance and richness Habitat area; when land is converted to producing bioenergy feedstocks Disturbance; factors that alter the physical environment (e.g. soil, hydrology) or vegetation (i.e. structure and/or composition), or simply deter or attract species Pollution that affects the composition and diversity of species communities by altering nutrient availability, acid deposition, and presence of toxins Invasion of non-native species (including pests and pathogens); aiding their initial colonisation, establishment and spread Habitat connectivity; factors that impact on the ability of species to move between habitat patches, which relate to physical and functional attributes of landscapes, including the area and quality of habitat patches, the extent to which they are influenced by edge effects from surrounding land use, the distance between habitat patches, and how easily species can traverse the intervening matrix.

Indirect land-use change (see ‘Land Use’ theme summary) and associated drivers of change may also potentially result in any of the impacts above, including where it leads to intensification of food, feed or fibre production. This is a particular concern in relation to increased cultivation of marginal land in the UK and to deforestation and forest degradation arising from UK bioenergy feedstocks sourced from elsewhere, including palm oil. Article 17(3) of the European Commission’s Renewable Energy Directive (2009) identifies that biofuels and bioliquids (taken into account for the purposes of measuring compliance with the Directive’s requirements for national targets and renewable energy obligations and eligibility for financial support) should not be made from raw material obtained from land with high biodiversity value (as defined below, on or after January 2008, whether or not the land continues to have that status): a. “primary forest and other wooded land of native species, where there is no clearly visible indication of human activity and the ecological processes are not significantly disturbed b. areas designated: i. by law or by the relevant competent authority for nature protection purposes; or ii. for the protection of rare, threatened or endangered ecosystems or species recognised by international agreements or included in lists drawn up by intergovernmental organisations or the International Union for the Conservation of Nature… unless evidence is provided that the production of that raw material did not interfere with those nature protection purposes; c. highly biodiverse grassland that is: i. natural, namely grassland that would remain grassland in the absence of human intervention and which maintains the natural species composition and ecological characteristics and processes; or ii. non-natural, namely grassland that would cease to be grassland in the absence of human intervention and which is species-rich and not degraded, unless evidence is provided that the harvesting of the raw material is necessary to preserve it…”. A summary of evidence reviewed for the biodiversity chapter is available as Appendix 10 to this report.

8.2 Summary of information in the literature The relative positive or negative impact of producing agricultural biomass depends on what systems/habitats it replaces and to what it is compared. The published literature generally makes comparisons with conventional agriculture and, in relation to oil palm plantations, with


42


primary or secondary forests. The statements below are intended to synthesise and broadly reflect information in the literature. Species Much research has focused on the impact at a species level, particularly in relation to birds, butterflies and plants. The degree and nature of the impact (positive or negative) is to some degree inevitably specific to individual taxonomic groups and species. SRC and energy grasses are generally reported as supporting a wider abundance and diversity of wildlife (both flora and fauna) when compared to conventional arable agriculture. Oil palm plantations are less species-rich than primary or secondary forest. Habitat area SRC and energy grasses provide habitats in agricultural landscapes for species with different requirements. Conversion of forests to oil palm plantation has a significant impact on community composition, which indicates oil palm plantations are unsuitable habitats for most forest species Habitat disturbance Biomass crops not harvested annually increase the biodiversity of agricultural landscapes. Pollution Conventional agricultural crops typically require greater inputs of fertiliser, herbicide and pesticide than other bioenergy crops. However, there has been little consideration of the impact of pollution on biodiversity from producing agricultural biomass. Invasion Research into the potential invasiveness of bioenergy crops has focused on energy grasses. Many papers are US-based. Reed canary grass can invade wetlands, affecting wildlife habitat. Miscanthus species are invasive or have the potential to be so. Although Miscanthus × giganteus does not produce viable seed, its sterility is not assured and vegetative propagation is often associated with invasiveness. Switchgrass shares many traits with Miscanthus and can also produce seeds, giving it greater invasive potential. Habitat connectivity Despite increasing interest at the science-policy interface in integrated landscape-scale thinking, there remains less research at a landscape-scale than at a site-scale of the impact of producing agricultural biomass. Key issues identified by Warwick HRI (2010), which are supported by a wider literature, are:  





The impact on biodiversity depends on the proportion of land converted to biomass production and its spatial distribution Biodiversity benefits from increased landscape heterogeneity33 and permeability34 provided by networks of small clusters of fields given over to biomass production, as compared with a single large site Whilst conversion of arable land enhances biodiversity associated with other habitats, it inevitably reduces connectivity between patches of suitable habitat for arable species Landscape heterogeneity decreases with greater synchronisation of harvest cycles over a longer time period, which thereby has the potential to reduce species diversity.

33

Generally, species diversity is greater in more heterogeneous landscapes. Landscape permeability is a measure of how easily an individual organism can move through a landscape. Increasing landscape permeability increases the resilience of individual species’ populations by allowing them to operate across multiple sites; it also enhances the adaptive capacity of species by enabling individuals to move across landscapes in response to change. 34


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8.3 Confidence in the results Table 8-1 below sets out the confidence in evidence of the impact on biodiversity of individual biomass feedstocks. There have been a number of research projects in a UK context on the impact of SRC on biodiversity, leading to high confidence in the evidence, although this has not considered the impact of pollution, as compared to agricultural crops, or potential for invasion and is less comprehensive in relation to landscape-scale impact on habitat connectivity. Much research on energy grasses is US-based, which may not be relevant to the UK, this is particularly true of work on the potential of energy grasses to invade semi-natural habitats. Evidence on annual crops is generally extrapolated from the wider literature on arable crop production rather than from research specific to biomass production. The impact of palm oil plantations has recently been systematically reviewed by Savilaakso et al. (2014) leading to high confidence in those aspects that have been researched. Table 8-1: Confidence in evidence of the impact on biodiversity of biomass feedstocks Feedstock

Species

Habitat area

Habitat disturban ce

Pollution

Invasion

Habitat connectivi ty

Energy crops SRC Poplar SRC Willow SRC Perennial grasses Miscanthus Switchgrass (Panicum) Reed canary grass (Phalaris) Sugar beet Oil seed rape Wheat Straw Palm oil from Indonesia Corn ethanol from US or Ukraine Sugar cane from Brazil or Guatemala

Medium High High High Medium Medium Medium



Low

Low

Low Low Medium

Medium Medium Medium Medium Low Low Low

Low Low Medium Medium

Medium

Medium

Low

Low

High

High

Medium Medium Medium

Medium Medium High

Medium Medium Low

8.4 Trends in the information In recent years, research into the impact of agricultural biomass production on biodiversity has focused on a number of specific themes:     

Undertaking and applying (systematic) reviews (e.g. NNFCC 2012, Savilaakso et al. 2014, Mudgal et al. in draft) Considering implications of evidence for sustainability standards and criteria (e.g. Frank et al. 2013, IUCN 2013) Impact of SRC (e.g. Baum et al. 2012, Langveld 2012, Fry and Slater 2011, Rowe et al. 2011) Invasiveness of energy grasses (e.g. Richardson and Blanchard 2011, Lonsdale and Fitzgibbon 2011) Landscape-scale impact (e.g. Warwick HRI 2010, Karp et al. 2010); and


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

Subsequent implications for ecosystem services (Alexandros et al. 2011).

8.5 Evidence gaps 8.5.1 Described in the literature In general, gaps described in the literature are specific to the classes of biodiversity impact and feedstocks studied and do not seek to identify gaps in the literature more widely. Wildlife and Countryside Link (2007) identified that at that time there had been very little research into the impact of energy grasses on biodiversity and highlighted both potential negative impact on species of open farmland (e.g. skylark, meadow pipit and lapwing) and potential positive impact on native plants with knock-on benefits for foraging by groundnesting birds and invertebrates. Semere et al. (2007) also identified that evidence on energy grasses relates to young crops, so evidence is lacking of the impact of canopy closure and increasing maturation on biodiversity. NNFCC (2012) identified that most research has compared the impact of production of agricultural biomass with annual arable crops and highlights a lack of evidence on the impact of planting bioenergy crops on land not in agricultural production. This may be because it is axiomatic that such land may be of existing conservation interest and thus any change in land use is likely to have a negative impact on biodiversity. More generally true of the production of bioenergy crops, Bourke et al. (2013) highlight in relation to Miscanthus and oil seed rape that there is insufficient evidence of the landscapescale impact of agricultural biomass production to understand implications for maintenance of ecosystem functioning and the delivery of ecosystem services. The recent systematic review by Savilaakso et al. (2014) identified several knowledge gaps about the impact of palm oil plantations cultivation on biodiversity: landscape-scale issues; implications of reductions in species richness and changes in community composition for ecosystem functions; and the impact of different production systems (smallholdings vs industrial estates) and management practices (certified vs non-certified plantations).

8.5.2 Gaps not described in the literature The review did not identify any papers addressing impact on biodiversity from production, transport and use of the following bioenergy feedstocks: straw; corn ethanol from the USA or Ukraine; and sugar cane from Brazil or Guatemala. Looking across all bioenergy feedstocks, all classes of biodiversity impact identified in Section 8.1 are addressed but in relation to individual types of feedstock there are many gaps (see Table 8-1).

8.6 Suggestions for further research 8.6.1 Described in the literature Suggestions for further research described in the literature reflect the gaps in evidence that it identifies, summarised in Section 8.5.1.

8.6.2 Further suggestions Existing evidence and associated confidence in findings, as well as gaps identified in the literature and identified from this rapid evidence assessment by Ricardo-AEA, suggest other wider or more specific potential research priorities in relation to the impact of agricultural biomass production on biodiversity and its mitigation:


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

    

Long-term monitoring of impact on species, which is identified as a need by Semere et al. (2007) specifically in relation to Miscanthus, however, there is a more general need in relation to all bioenergy crops Projected impact of direct and indirect land-use change on habitat area, particularly in relation to marginal land in the UK Impact of pollution from agricultural biomass production as compared with annual arable crops Invasiveness of energy grasses in a UK context Impact of edge effects from agricultural biomass production on adjacent semi-natural habitats, as compared with edge effects from annual arable crops Landscape-scale impact, particularly in relation to energy grasses in the UK, and palm oil plantations.


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9 Water use 9.1 Summary of current issues Impacts of water use and therefore water availability and the risk of flooding have been identified as a major issue for all bioenergy feedstocks which can result in both positive and negative consequences. This needs to be considered at both a policy and strategy level but also in terms of site specific considerations. UK water resources are coming under increasing pressure due to issues such as climate change and population growth. Short duration droughts (12-18 months) similar to the major drought of 1976 are predicted to become more common. Changing rainfall patterns will have an impact on river flows and groundwater recharge with recent modelling indicating a decrease in river flows in the summer across most of England and Wales. Defra are currently consulting on changes to the abstraction licencing system and looking at how to meet Good Ecological Status as part of the EU Water Framework Directive, the impacts at a catchment scale of land management on water resources is an important aspect of both of these. The drought in 2012 resulted in environmental impacts from extremely low river and groundwater levels with resulting impacts on water supplies and the introduction of temporary use bans for household customers. Climate change variability has also been linked to increasing floods. The 2012 drought was broken by serious flooding across the country and in 2013/2014 there have been more flooding issues in England and Wales. This has led to questions about land management approaches and farming, how they are related to flooding and the potential for changes to increase resilience to flooding in future high rainfall events. This section provides a summary of the literature around the impacts of bioenergy and biofuels on water availability and flooding. Water quality impacts are also a consideration, however these have been assessed and summarised in a separate theme summary. Water use impacts need to be considered within this broader context and also within the wider social and economic perspectives presented in the overall report. A summary of evidence reviewed for the water use chapter is available as Appendix 11 to this report.

9.2 Summary of information in the literature The information in this section is summarised by the sub themes of crop water use and flooding considerations. The impacts on water use are usually specific to species and this is outlined in detail also. The focus in the literature in relation to direct impacts in the UK are around short rotation coppice and grasses rather than palm oil, corn ethanol and sugar cane grown outside the UK and this is reflected below.

9.2.1 Crop water use 9.2.1.1 Short rotation coppice – poplar and willow High evapotranspiration rates from traditionally riverine growing tree species such as poplar and willow has led to concerns about their impacts on water availability. However, there is agreement within the literature that this is site specific and dependent on rainfall and should be compared with the alternative land uses (e.g. arable crops or other hardwood forest types).


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Short rotation coppice (SRC) has been found to result in a 10-15% reduction in hydrologically effective rainfall compared with arable crops in the UK. In general the evapotranspiration (water use) from this crop is higher than arable crops but lower than other forest types. Based on field studies, there are conflicting reports on the range of evapotranspiration rates compared with other crops. For example, one study observed only a 50mm/year difference compared with other crops while another study observed infiltration three times less than arable crops. SRC poplar has been observed to have yield equal to willow with a better water use efficiency. A field study of SRC willow observed a 40% reduction in groundwater recharge compared with a fallow reference plot, however low soil water storage capacities reduced transpiration and moderated the impact. A shorter coppice harvest rotation is suggested to increase groundwater recharge as less rainfall interception occurs in the first year after harvesting. A study from the use of SRC for shelter belts in Mid-Wales reported reduced runoff from slopes with enhanced infiltration. A broader UK modelling approach for SRC suggested planting only in areas with 600mm of rainfall or more. The impact of riparian buffer strips on water availability at a catchment level35 should be minimal compared with wider water abstraction, however there are potential impacts in headwaters and for small streams. Catchment scale impacts of SRC plantations on hydrology have been suggested to be negligible as long as they are not planted in extensive areas of a single catchment. 9.2.1.2 Miscanthus, switchgrass, reeds Miscanthus appears to use less water than SRC, being more water efficient due to C4 photosynthesis, however yields are water limited in many areas of the UK. Miscanthus sinesis was observed to have a flexible water saving strategy and have a different response to drought effects. Overall C3 grasses have been suggested to be suitable at any latitude, however warmer conditions are needed for C4 grasses such as Miscanthus and switchgrass. A lower evapotranspiration rate and impact on groundwater compared with SRC suggests Miscanthus as a better crop choice for dry regions such as East Anglia. However, potential impacts of large plantations in the South-West of England have been recognised in Devon and Cornwall where 90% of water supply is from surface water and there are constraints during summer with holiday population water usage.

9.2.2 Flood risk 9.2.2.1 Short rotation coppice – poplar and willow Flood risk reduction from SRC plantations and buffer strips is a potential benefit identified throughout the literature. Upstream use of SRC buffer strips can reduce river response times to rainfall and could be considered as a possible way to reduce flooding. Positive benefits on average stream flows and for reducing annual floods have been suggested for SRC plantations in Northern Minnesota compared to other forest types. A wider study suggested floodplains have potential for large scale biomass systems based on polar and willow along with other biofuel crops. However, this study also highlighted potential for delayed harvesting until water levels recede and this may impact on the cost to produce the feedstock due to an increased drying requirement. 9.2.2.2 Miscanthus, switchgrass, reeds Miscanthus has been observed to result in drying of the soil profile and result in an 18 to 21% increase in interception. Switchgrass has also been identified as having benefits in flood plain areas and has been shown to be adapted to flooding also with 40% more biomass under flooded conditions than controls.

35

Riparian buffer strips are where trees are used primarily to reduce surface runoff and treat this before it reaches rivers. The amount of water lost through evapotranspiration may have a large impact on headwaters and small streams as there is less water available to begin with.


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9.3 Confidence in the results The confidence ranking based on review of individual papers and agreement across papers (Table 9-1). Table 9-1: Confidence in evidence of water use of biomass feedstocks Water supply

Flooding

SRC

Miscanthus, switchgrass, reeds

SRC


Low Agreement Medium Evidence

Medium Agreement Medium Evidence

Medium Agreement Medium Evidence

Medium Agreement Low Evidence

There is a medium level of evidence on the specific crop types related to water supply or flooding impacts. However, there are conflicts within the evidence presented and more review and modelling papers than field studies.

9.4 Evidence gaps 9.4.1 Described in the literature A major gap outlined in the literature is site specific impacts and water use considerations for SRC. Further field trials are required to establish the ranges of evapotranspiration, infiltration and interception of surface flows. Additionally, developing this into regional models, as well as those that can be used to assess individual biofuel site applications, has been suggested as useful from a policy perspective.

9.4.2 Gaps not described in the literature The interactions with other abstraction, including public water supply, requires further investigation. Additionally, following the focus on land management and flooding after the 2013/14 flood there is a need to consider how these crops can provide benefits for flood risk by either replacing arable crops or through the use of SRC shelterbelts.

9.5 Suggestions for further research 9.5.1 Described in the literature Site specific impacts and water use considerations for SRC should be further assessed. Jon Finch at the Centre for Ecology & Hydrology (CEH) is currently investigating water balances of Miscanthus and Willow using modelling and site measurements in comparison with wheat and other crops. Research at the University of Southampton is looking to adapt the JULES land system model for the UK to account for water use efficiency and also specific differences between willow and poplar.

9.5.2 Further suggestions There is a need to consider bioenergy within the context of wider water use planning being undertaken in the UK. The Environment Agency is considering the impacts of power generation specifically as part of their case for change for reforming abstraction licencing and biofuels should be considered at this level. Potential impacts on Water Company planning and water source yields within the context of flow requirements for the Water Framework Directive should be considered as well as wider flood impacts. To enable the modelling outputs from academic research should be readily applicable to industry modelling approaches and researchers should link-up with the Environment Agency and Water Companies to ensure this happens. Ref: Ricardo-AEA/R/ED59367/Issue FINAL

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10 Water quality 10.1 Summary of current issues Water quality impacts of biofuels and bioenergy compared with other crop types is an important consideration for policy in the UK. The EU Water Framework Directive (WFD) is the primary driver for water quality improvements and setting standards for good ecological status. The status of water bodies varies across the UK with a substantially higher proportion of those in Scotland being of good status, as compared to England and Wales. Overall, the ecological and chemical status of 18.7% of surface-water bodies was good but is only projected to rise to 21.3% by 2015. The ecological potential of 26.4% of heavily modified and artificial water bodies was good (29% projected for 2015) and 23.2% achieved a good chemical status (rising to 23.7% in 2015). 73.7% of groundwater bodies were chemically of good status (expected to be 79.3% in 2015) and 79.2% had good quantitative status (anticipated to increase to 80.2% by 2015). Diffuse water pollution represents the most significant pressure on surface water bodies in the UK. Up to 82% of rivers, 53% of lakes and 75% of groundwater bodies in the UK are ‘at risk’ from diffuse pollutants including nitrate and phosphorous. This paper provides a summary of the literature around the pressures of bioenergy and biofuels on water quality. Water availability and flooding are also considerations, however these have been assessed and summarised in a separate theme summary chapter. Water quality impacts need to be considered within this broader context and also within the wider social and economic perspectives presented in the overall report. A summary of evidence reviewed for the water quality chapter is available as Appendix 12 to this report.

10.2 Summary of information in the literature Crop

Water quality benefits

Water quality issues

SRC – Polar and Willow

Reduced nitrate losses, surface runoff and pollutants.

Potential sediment impacts during harvesting, however likely to be less than existing land use

Miscanthus, Switchgrass, Reeds Switchgrass filter strips reduce Potential phosphorous leaching nitrogen and phosphorous losses when irrigated with wastewater Crops outside the UK

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Increased nitrogen and carbon losses from corn production

10.2.1 Short rotation coppice – poplar and willow Short rotation coppice (SRC) has been suggested to have potentially positive benefits for improving water quality in catchments due to:  

the lower fertiliser and pesticide inputs than used for traditional crops the interception of pollutants in surface water runoff when it is used as riparian buffer strips.

The nitrate implications for Nitrate Vulnerable Zones in the UK have been specifically assessed. Nitrate losses have been found to be small compared with autumn peaks in arable


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crops although there are significant losses at establishment and during removal of stands. Overall, over the 15-30 year lifetime, SRC has been found to reduce nitrates in groundwater but there may also be a small increase in phosphorus in surface water over time. Phosphorus runoff is mostly related to the common practice in the UK and Sweden of applying municipal sewage sludge to bioenergy crops. Although there will be an excess of phosphorous applied in the sewage sludge, binding with soil particles will occur. Phosphorus groundwater drainage concentration was under detection limits based on measurements taken over two vegetation periods. Maintaining soil cover and reducing ground disturbance over the whole year, compared with arable crops, reduces surface water runoff and the pollutants in this also. Studies in the UK have found low nitrogen concentrations in groundwater even with intensive fertiliser application to SRC. One study observed 16kg N/ha leaching for SRC compared with 70-120 kg N/ha for different cereal crops. A phosphorous retention rate of 95% for willow and 94% for poplar has been observed also, however future increased leaching may result from higher fertiliser loading.

10.2.2 Miscanthus, switchgrass, reeds Miscanthus, switchgrass and reed species have also shown potential to improve water quality either through their use in buffer strips or as stand-alone cropping. The use of organic fertiliser through land spreading of organic by-products is increasing in general. Miscanthus has a low nitrogen requirement and uptake which matches well with wastewater sludge. Field observations have observed a potential increase in phosphorous leaching when Miscanthus is irrigated with waste water, however there is no indication of heavy metal build-up in the soil or groundwater. Studies focussing on switchgrass have observed increasing yield with manure application. Application in filter strips reduced phosphorous in surface water runoff by 46% and nitrogen in surface runoff by 76%. As a result this crop can still function as an effective buffer strip to manage surface water runoff even when manure is applied as a substitute for inorganic fertiliser.

10.2.3 Crops outside the UK Water quality impacts also arise from corn production for ethanol in the USA. This has led to development of greater modelling capacity in the USA through the Soil and Water Assessment Tool (SWAT). This has highlighted reduced streamflows and increased nitrogen and carbon losses with greater corn production. An increase of 10-37% nitrates in runoff has been projected with increased corn ethanol production in order to meet the Energy Independence and Security Act 2007. When using the US EPA Soil and Water Assessment Tool, precipitation and temperature were identified as key factors influencing the outputs. Climate change, and its impacts on these factors, was found to increase pollution potential from increased corn production. Additionally removal of corn stover (the remains of plant once harvested) has implications for runoff and pollution. Implications for the UK arise in the case of corn and corn stover, which may be increasingly grown in the UK.

10.3 Confidence in the results The confidence ranking based on review of individual papers and agreement across papers(Table10-1).


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Table 10-1: Confidence in evidence of the impact on water quality of biomass feedstocks Water quality SRC


Crops outside the UK

Medium agreement Medium evidence

Medium agreement Low evidence

Medium agreement Robust evidence

There is medium-level agreement within the papers on the water quality impacts of bioenergy. However, there is limited evidence for some crops and a range of evidence gaps are identified in the literature.

10.4 Evidence gaps 10.4.1 Described in the literature The impact of nitrogen from organic wastes at high application rates also needs to be considered. As this isn’t allowed in nitrate vulnerable zones there is a deterrent for farmers unless it can be shown that SRC crops can enable use of organic wastes in these areas. There is also a need for SRC species specific research on uptake of nitrogen. Another gap within the literature is the need to consider SRC and buffer strips within a landscape scale approach.

10.4.2 Gaps not described in the literature A gap not described in the literature is the need for regional modelling for water quality and potential to join-up with wider modelling exercises being undertaken for the WFD in catchment based approach pilots. Longer term assessment of phosphorus leaching from the application of municipal sewage sludge to SRC requires further research.

10.5 Suggestions for further research 10.5.1 Described in the literature Use of willow and poplar SRC on marginal soils needs to be considered as well as current studies focussing on replacement on productive agricultural soils.

10.5.2 Further suggestions There is potential to link scenario analysis of biofuel/bioenergy crop deployment with existing modelling approaches for WFD and catchment management to understand potential impacts at a regional scale using a range of scenarios.


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11 Further gaps identified As no information could be found on risks from contaminated feedstocks e.g. aflatoxininfected corn, dioxin-contaminated veg oils, this is a gap requiring further research. Some suggestions for further research were identified in more than one theme:     

Impacts on marginal soils in terms of biodiversity, yields and economic performance, water use and water quality Integrated assessment of optimal land use, e.g. in terms of food, fuel, water availability, biodiversity and social issues, as well as bioenergy The use of bioenergy crops in integrated farming. Landscape- or catchment-scale Up-to-date guidelines for growers on bioenergy crops and their impacts on water quantity, water quality and biodiversity.

Finally, there is a considerable amount of relevant ongoing research in the UK. We discussed this with some of the key researchers and incorporated this information where relevant; however, it is important to note that research in this area is not static.


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Appendices Appendix 1: Air quality Appendix 2: Detail of literature searches Appendix 3: Organisations that provided information Appendix 4: Glossary Appendix 5: Current state of the market evidence-base spreadsheet Appendix 6: UK agricultural production impacts evidence-base spreadsheet Appendix 7: Socio-economics evidence-base spreadsheet Appendix 8: GHG-mitigation potential evidence-base spreadsheet Appendix 9: Land-use change evidence-base spreadsheet Appendix 10: Biodiversity evidence-base spreadsheet Appendix 11: Water use evidence-base spreadsheet Appendix 12: Water quality evidence-base spreadsheet

Ref: Ricardo-AEA/ED59367/Issue FINAL


Appendix 1 – Air quality Summary of air quality issues Overview Air quality impacts from large plant (whether gasification or more traditional conversion technologies) are controlled through site-specific controls based on Best Available Techniques and are regulated to avoid or minimise impacts on air quality. However controls on smaller installations are currently limited in the UK and do not directly address modern air quality standards. For conventional biomass conversion technologies at the smaller scale36, widespread uptake of biomass use has the potential of a negative impact on air quality compared to gas and liquid fuels and technologies that biomass would replace. Future EU controls (Ecodesign, Medium Combustion Plant Directive) will set minimum requirements and are designed to protect air quality (at an EU level). However, these controls are not agreed yet and may not provide the scale of emission reductions needed to achieve required air quality improvements in the UK or other Member States.

Air quality Air pollution poses risks to human health, the built environment and natural ecosystems. The UK is affected by both domestic emissions and long-range trans-boundary emissions from other countries. This means that air pollution is a mix of impacts from many sources of which biomass combustion is one and air quality regulations have to be enforced with regard to all of these pressures. Poor air quality is a major health risk with children, the elderly and citizens suffering from asthma and respiratory conditions the most affected. Air pollution also affects the quality of fresh water, soil, and ecosystems. Key air quality pollutants associated with combustion of biofuels include:   

Particulate matter – health concerns focus on particles smaller than 10µm (PM10) and smaller than 2.5µm (PM2.5). Nitrogen oxides (NOx) – health impacts from formation of ‘secondary’ PM and ground-level ozone, also acidification impacts. Volatile organic compounds (VOC) - health impacts from formation of ‘secondary’ PM and ground-level ozone.

Other relevant air quality pollutants for combustion (particularly small-scale combustion) include Polynuclear Aromatic Hydrocarbons (PAH), Black Carbon and Sulphur Dioxide (SO2). The UK meets European air quality standards for nearly all pollutants. The main challenge is in meeting nitrogen dioxide limits alongside roads in cities and towns. Exceedances were reported (Defra, 2013) in 2012 over much of the UK for the long term ozone objective for human health and for, some areas, the long term ozone objective for vegetation. Parts of the UK have also exceeded the air quality target value for Benzo(a)pyrene (an indicator for PAH). A target air quality concentration for PM2.5 will become a limit in 2015 with a requirement to achieve a reduction in Average Exposure Index (AEI) by 2020. Achievement of future PM2.5 air quality limits are of concern to the UK and many other EU Member States because background concentrations are relatively high (that is there is limited headroom in some areas). Total PM2.5 emissions in Europe will critically depend on the use of small stationary sources – in particular solid fuel use for heating in the domestic sector (IIASA, 2013). 36

For example, heating boilers for commercial or institutional space heating burning wood pellets or wood chip; residential room heaters and central heating boilers burning wood logs, pellets or chips.

Ref: Ricardo-AEA/ED59367/Issue FINAL


A number of international agreements set air quality standards, impose emission limits, or set national or regional emission ceilings for pollutants. The UK is a party to the international agreements, also implementing agreements through EU legislation. The international agreements and EU legislation are dynamic, are reviewed periodically and amended when need arises. For example, to accommodate the interdependence of air pollution and climate change policies. Longer-term action could include controls to limit black carbon emission, primarily for climate change but also to reduce health impacts associated with fine and ultrafine particulates. The EC has recently reviewed air quality policy37 and proposed emission reductions for certain air pollutants and a new Medium Combustion Plant Directive to control air pollutant emissions from 1-50 MWth combustion plant. The proposed Directive is intended to complement existing legislation for combustion installations and plant ≥50 MWth and proposed Ecodesign regulations for smaller combustion plant (including domestic appliances). The Directive is also necessary to avoid possible trade-offs between air quality and increased biomass use, which may otherwise result in increased air pollution. The World Health Organisation (WHO) International Agency for Research on Cancer (IARC) (WHO IARC, 2013) has recently classified outdoor air pollution and particulate matter as carcinogenic to humans.

Emission sources Combustion activities range from open fireplaces burning wood logs and used for domestic heating to large power station boilers which either co-fire biomass alongside conventional fuels or burn only biomass fuels. Liquid biofuels can be burned in boilers or engines. Gaseous biomass may be suitable for burning in engines (for example landfill gas engines, sewage gas engines), gas turbines or boilers/furnaces. The technologies applied tend to reflect the type and characteristics of the fuel. In the domestic sector, room heaters burn wood logs or pellets and boilers will burn logs, pellets or chips. Larger appliances burn pellets or wood chip and boilers in industry burn a wide range of biomass materials. Domestic appliances range from room heaters of perhaps 4-10kW output to 50 kW output boilers. Small combustion sources extend to about 1 MWth (thermal input), medium scale are 1-50 MWth and large scale 50 MWth or larger. For small and medium scale biomass combustion plants in the UK, the principle control of emissions is the Clean Air Act 1993 which is currently under review. The Renewable Heat Incentive regulations38 include emission requirements (for Particulate Matter and Nitrogen Oxides) to mitigate the impact on air quality of the incentivised increase in biomass use in boilers . Small scale combustion sources (