ENVIRONMENTAL IMPACTS OF THE ENERGY PRODUCTION FROM FOREST BIOMASS IN PORTUGAL Costa, T. P., Arroja, L., Quinteiro P., Tarelho, L. A. C., Dias, A. C. Centre for Environmental and Marine Studies (CESAM) & Department of Environment and Planning. University of Aveiro, 3810-193 Aveiro, Portugal. E-mail:
[email protected];
[email protected]
Introduction and objectives Electricity production from forest wastes is one of the most important future markets for biomass worldwide. This is due to the relatively low costs and easy access of the wastes. In Portugal, the furnaces most used for the energy production from forest biomass are the fluidized beds (11 plants in operation with an installed capacity of 298 MW) and the grates (9 plants in operation with an installed capacity of 155 MW) (E2p, 2017). However, studies are needed to evaluate the impacts related to this activity and the Life Cycle Assessment (LCA) methodology can provide a comprehensive quantification to support decisions. The aim of this study is to assess the environmental impacts, by means of LCA, resulting from the conversion process of forest logging residues from eucalyptus into electricity in Portugal considering three types of different supply chains and two types of technologies: grate furnaces and fluidized bed furnaces.
Methodology
Results Figure shows the environmental impact assessment results associated with each stage of the production of 1 kWh of electricity from the combustion of forest residues
The functional unit is the production of 1 kWh of electricity to the national grid. The impact assessment methodology implemented to carry out the study was the ILCD (JRC-IES, 2010).
System boundary
180
0.9
Site preparation (clearing, scarification, fertilization)
Forest
Stand tending (cleaning, fertilization, selection of coppice stems)
120
100
Logging (with harvester) Residues in forest floor
Wood
Transportation
Transportation
processing and transportation
Transportation
Unloading
Unloading
Chipping
Loading
Transportation
Unloading
Unloading
Loading
Transportation
Unloading
Energy conversion
Power plant -Grate furnace (S2A) -Fluidised bed (S2B)
Power plant -Grate furnace (S3A) -Fluidised bed (S3B)
For all the impact categories analyzed, the biomass supply chain to produce electricity with smaller impacts is the one in which the logging wastes are collected and chipped at the roadside, due to a lower diesel requirement in transport and loading/unloading operations when compared with the bundling system.
Regarding the energy conversion technology, the fluidized bed furnace has a better environmental performance than grate furnace in all selected impact categories.
*
0.4 0.3
20
0.1
0
0 S1B
S2A
S2B
S3A
S1A
S3B
S1B
S2A
S2B
S3A
S3B
S2B
S3A
S3B
S3A
S3B
4.5 0.0045 4.0
0.0040
3.5 3.0 2.5 2.0 1.5 1.0
0.0035 0.0030 0.0025 0.0020 0.0015 0.0010
0.5
0.0005
0.0
0.0000 S1B
S2A
S2B
S3A
S1A
S3B
2.0
1.0
1.8
0.9
1.6 1.4 1.2 1.0 0.8
0.6 0.4
0.0 S1A
S1B
S2A
S2B
Forest management
Conclusions
0.5
0.2
0.2
Power plant -Grate furnace (S1A) -Fluidised bed (S1B)
0.6
40
S1A
Chipping
0.7
Mineral and fossil depletion (mg Sb-eq)
Loading
Loading
Marine eutrophication (g N-eq)
Collection,
Loading
Forwarding (with forwarder)
Photochemical ozone formation (g NMVOC-eq)
Bundling
Chipping
60
S1A
Residues for energy
Forwarding (with forwarder)
80
Acidification (molc H+-eq)
management
Climate change (g CO2-eq)
Planting
140
Infrastructure establishment (road and firebreak building and maintenance)
0.8
Particulate matter (g PM2.5-eq)
160
S3A
S3B
S1B
S2A
0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 S1A
S1B
Collection, processing and transportation
S2A
S2B
Energy conversion
References JRC-IES, 2010. ILCD handbook. General guide for life cycle assessment - detailed guidance. Ispra, Italy. Dias, A.C., 2014. Life cycle assessment of fuel chip production from eucalypt forest residues. Fuel 4, 246-253. https://doi.org/10.1016/j.fuel.2012.02.053. E2p, 2017. Energias endógenas em Portugal. URL http://e2p.inegi.up.pt/?Lang=PT#Tec2
Acknowledgments The authors would like to thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ - Brazil), the financial support to CESAM (UID/AMB/50017 - POCI-01-0145-FEDER-007638), to FCT/MCTES through national funds (PIDDAC), and the cofunding by the FEDER, within the PT2020 Partnership Agreement and Compete 2020 and to the project SABIOS (PTDC/AAGMAA/6234/2014) funded under the project 3599-PPCDT. Ana Cláudia Dias also thanks FCT for funding (IF/00587/2013). MINISTÉRIO DA CIÊNCIA, TECNOLOGIA E ENSINO SUPERIOR
