Development of Life Cycle Impact Assessment By Using NETS Scheme

Development of Life Cycle Impact Assessment By Using NETS Scheme Sate Sampattagul1, Sadamichi Yucho2, Kato Seizo2 and Tanongkiat Kiatsiriroat1 1 Chiang Mai University, Mechanical Engineering Department, Thailand 2 Mie University, Department of Mechanical Engineering, Japan Abstract Operation of grid power plants involves directly environmental burdens like fossil fuels depletion, global warming, rain acidification, etc. The LCIA (Life Cycle Impact Assessment) of the fuels, and power plants for grid electricity, therefore, is strongly required towards further environmentally friendly technology. In this paper, a newly consolidated LCIA scheme "LCA-NETS" (NETS: Numerical Eco-load Total Standardization) is first developed from the internationally objective criterion. This scheme is then applied to the fuels of petroleum, coal, LNG and nuclear from overseas and respective fuel-fired power plants on the basis of widely collected inventory data. Discussion of the analyzed results is made on the LCIA results compared with renewable energy plants and further eco-improvement strategy. Keywords Life Cycle Assessment (LCA), Life Cycle Impact Assessment (LCIA), Power plants, Fossil fuels, Electricity, LCA-NETS 1 INTRODUCTION Operation of grid power plants and fuel acquisition directly generate impacts on environment such as fossil fuels depletion, global warming, and rain acidification. It is necessary to analyze and evaluate such impacts with LCA (Life Cycle Assessment), and to take measures to improve environmental performance. There are some LCA studies related to fuels and electricity in Japan. One of them can be found in Petroleum Energy Center where emissions of CO2, NOx and SOx through fuels’ lifecycle are analyzed and estimated in detail. As for power plant, CO2 and CH4 emissions including plant construction phase are analyzed by Uchiyama and Hondo in Socioeconomic Research Center.

In this study, we propose LCIA methodology ‘LCA-NETS’ to evaluate impacts for industrial products. It is developed focusing on 4 characteristics; (i) not depending countries or areas, (ii) not including weighting factor based on a subjective viewpoint, (iii) calculation based on objective data, (iv) conversion from LCI results into impact by using a simple thinking. In this paper, first the summary of developed methodology LCA-NETS is described and it is applied to the lifecycle of fuels, power generation plants and generated electricity to evaluate their impact on environment. Then environmental performance for those in Japan is discussed.

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THE SUMMARY OF LCIA METHODOLOGY ‘LCANETS’ Our developed methodology needs objectivity not depending a specific area, country or value since it aims at the evaluation of industrial products distributed internationally. The basic idea of ‘LCA-NETS’ is based on the balance between ‘Loader’ that generates an impact and ‘Receiver’ that suffers the impact. In this way of thinking, the maximum amount of environmental factor substance that the Loader can emit or consume is equal to the maximum of impact that Receiver can endure. The balance equation for environmental factor i in an impact category j is

However, the most important thing is not only such LCI (Life Cycle Inventory) analysis like LC-CO2 emission, but also assessment of impact caused by these emission, such as global warming, water and air pollution, rain acidification, ozone-layer depletion, waste issues, naturalresources depletion and especially fossil-fuels depletion involved in energy security. It is needed to analyze and evaluate impacts from a LCIA (Life Cycle Impact Assessment) viewpoint that integrates these impacts and to find out methods to improve environmental performance. There are nowadays some LCIA methodologies. One of typical methodologies is called DtT (Distance to Target) methods that convert LCI results into a single unit with weighting factor by the use of Government’s goal or regulation. These are, for example, Ecopoint in Switzerland and JEPIX in Japan. Another typical methodology are damage-oriented method such as EcoIndicator99 in Netherlands, Impact2002+ in Switzerland, EPS in Sweden and LIME in Japan. In this method, damage for protected targets is estimated with the aid of modeling of environmental mechanism and fate analysis.

j j j MEVi = Pi × ELMi [NETS]

(1)

where the unit of [NETS] (Numerical Eco-load Total Standardization) expresses impact on environment. If Receiver is mankind, a maximum impact that people can endure is 100 NETS per capita. ‘100 NETS per capita’ indicates the situation where people in the area affected by the impact cannot keep their past lifestyle unless they change their lifestyle. For example, in the situation in an impact category of Fossil-fuels Depletion, people must seek an alternative fuel due to depletion of a fossil-fuel such as petroleum depletion. In the case of ‘Air Pollution’, people in the area have to see doctors due to disease caused by polluted air.

However, in the case of power plants and fuels that are distributed all over the world through countries and areas, it is indispensable to use a common viewpoint and rational criteria. Therefore, it would appear that the methods described above are not suitable because studied range is restricted a specific country or area in DtT methods and modeling methods are under study in damage oriented methods.

j MEVi (Maximum Eco-load Value) in left side of eq. (1) indicates the total impact that Receiver (people) can endure and is 100 NETS per capita multiplied by population of mij in the area affected by the impact.

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Mining for crude oil for power generation is the process where crude oil under ground is brought up on the ground and then transported to the nearest port after removal of its impurities. The data related to environmental factors is investigated for every mining site because the amount of environmental factors varies by site. Associated gas for flaring is estimated from GOR (Gas Oil Ratio) and flaring ratio in every area. The amounts of emissions for CO2, SO2 and NO2 are estimated by using the amount of associated gas, unit gas emissions and self-consumed energy. The data of raw materials for facilities is calculated from data reference and energy consumption for its construction is assumed to be 20% of manufacturing energy for all materials. The life time of facilities is commonly set at 30 years. After mining, crude oil is transported by tankers. In this process, gas emissions, consumed fuels and losses due to VOC are estimated from capacity of tanker, the amount of transported crude oil, fuel efficiency and transportation distance for each sea route. The amount of environmental factors in construction for tankers and manufacture for facilities in plants are calculated with the use of inventory

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1.0E-05 5.0E-06 U ranium

0.0E+00

M ining & Pre-treatm ent (Prim ary) Land transportation Sea transportation Pre-treatm ent (Secondary) (a) for respective processes 100% 80% 60% 40% 20% 0%

U ranium

3.2 LCI analysis LCI analysis for fuels including petroleum, coal, LNG, Uranium is implemented on the bases of hearing investigation and literature research. In this paper, the LCI creating method for petroleum is described blow as an example.

2.0E-05 1.5E-05

LN G

3.1 System Boundary Fuels for power generation in Japan are mainly petroleum, coal, natural gas and uranium. In this study, impacts generated through fuels provision to Japan is analyzed from an objective viewpoint by ‘LCA-NETS’. Provision of fuels is divided into processes including mining, primary treatment, land and sea transportation, secondary treatment and domestic transportation. The functional unit for 4 fuels is set at 1 MJ. This study considers materials, energy and fuels as input, and gas emissions and wastes as output in each process as well as facilities, their construction, maintenance and operation. Environmental factors related to 8 impact categories described above are considered.

2.5E-05

LN G

LCA OF FUELS FOR POWER GENERATION

3.0E-05

C oal

3

3.5E-05

C oal

j In the LCA-NETS, ELMi is derived from eq. (1) by setting j j Pi and MEVi for each impact category, including Fossilfuels Depletion, Natural-resources Depletion, Global Warming, Ozone-layer Depletion, Air and Water Pollution, j Rain Acidification and Waste. Pi is set by objective data published by the United Nations, governments, academic j societies and industrial organizations. The value for Pi is kept updated.

3.3 The result of LCIA LCA-NETS are applied to the LCI results of fuels for power generation. Obtained LCIA results are shown in Fig. 1.

O il

j On the other hand, Pi in right side of eq. (1) is the maximum value of an environmental factor that Loader j can emit or consume. The unit of Pi depends on the environmental factor such as kg, kWh, etc. Therefore j ELMi (Environmental Load Module) [NETS/(kg, kWh, …)] is a unit-conversion coefficient and expresses an impact per emission or consumption of environmental factor i in an impact category j.

O il

j mi is the world population in the case of an impact in global scale such as global warming and resources depletion.

database developed by authors. These LCI data such as metals and fuels depend on areas or countries producing them. If such necessary data is not available, it is replaced by Japanese data. Calculated environmental factors in each area are converted into the amount per 1 MJ with weighted average with imported crude oil, its density and its heating value. LCI for coal, LNG and Uranium is also created by similar methods and converted into the amount of environmental factors per 1 MJ.

Life C ycle Im pacts [N ETS/M J]

(2)

Im pacts ratio

MEVij = 100 mij [NETS]

Fossil-fuel D epletion N atural-resources D epletion G lobal W arm ing O zone-layer D epletion W ater Pollution A ir Pollution R ain A cidification W aste Issues

(b) for impact categories Fig. 1 Life cycle impact of fuels, per 1 MJ.

‘a’ in this figure shows impacts for each fuels on every process including mining, primary pre-treatment, land and sea transportation and secondary pre-treatment. ‘b’ shows percentage of impacts in each impact categories. Total impacts per 1MJ for each fuel are, if the impact of

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petroleum is 1.00, 1.79 (LNG), 1.28 (Coal), 1.00 (Oil) and 0.14 (Uranium) in descending order.

and thermal efficiency is calculated by using collected data (Table 1).

The reason that the impact of LNG is larger than other fuels is that large energy consumption in its liquefaction process (shown in mining and pre-treatment in fig (a)). The natural gas in its producing countries or their neighboring countries isn’t needed to liquefy and is transported by pipelines. The impact in 100 km of pipeline transportation is about 20 % compared with transportation to Japan with liquefaction. This fact implies the necessity to retrieve the most of large energy added in liquefaction when LNG gasification.

Table 1 Specifications for selected power plants.

The impacts of sea transportation for petroleum and coal are 52 % and 73% of all their impact respectively. The reason is the impact of rain acidification due to NOx and SOX generated in fuel combustion from tankers. This result implies the necessity of regulation of gas emission for ships. The impact of oil refinery process is added to that of crude oil when petroleum products such as gasoline, diesel oil, kerosene and heavy oil are used. The reason that the impact of uranium is remarkably small is that heat value of uranium is greatly large than other fuels. This means that uranium is most effective fuel for power generation. The risk of uranium is not considered in this paper, but LCA-NETS needs to include assessment of it in the future. The impacts of each fuel depend heavily on their type of transportation from their process viewpoint. From viewpoint of impact category, measures for fossil-fuels depletion and rain acidification are more important than those for global warming. These results indicate the importance of effective use for coal and recycling technique for Uranium in Japan.

S teel,A lum inum ,H eavy oil,C oncrete,…

Fuel procurem ent

P ow er generation

W aste processing

OUTPUT S olid W aste,C O 2,C H 4,S O x,N O x,…

OUTPUT

INPUT

Electricity 1kW h (P roduct)

4 LCA OF POWER GENERATION 4.1 System Boundary Electricity in Japan is generated at crude-oil fired, coalfired, LNG-fired, LNG-fired (combined cycle), Nuclear power plant. In this chapter, LCIA for 1 kWh of electricity is implemented. As shown in Fig. 2, System boundary includes power plant of operation, maintenance, construction and waste disposal.

Power

Capacity

Operation

Thermal

[MW]

Ratio

Efficiency

Coal fired

700

95%

44%

Oil fired

700

40%

39%

LNG fired

700

65%

41%

LNG-CC

1700

55%

49%

Nuclear

1100

80%

33%

plant

State of the art LNG-CC (Combined cycle) power plant studied here has high thermal efficiency but its plant availability is small than coal and nuclear power plants which cover base electricity demands in Japan. MOX fueled nuclear power plant is not operating as commercial plant and most of those data is kept undisclosed. The inventory data of this plant is estimated by the use of the data in papers and our inventory database, about the material use in construction and facilities and consumed fuels. As for other basic parts, the inventory data of a conventional nuclear power plant is used here. Waste disposal processes for each power plant are treated as follows. ・ The coal ash generated in coal fired power plant is transported to landfills except the amount of utilized coal ash. ・ The way of waste disposal in nuclear power plant is based on scenario in the paper where spent nuclear fuel is stored for 50 years and where LLW (Low Level radioactive Waste) generated in fuel processing and plant operation and dismantling is reclaimed after its cement solidification. Material use and its manufacture for the landfill and solidification (steel, concrete, glass, etc.) are considered. Spent nuclear fuel in MOX fueled power plant is recycled after fuel reprocessing. HHW (High Level radioactive Waste) generated in reprocessing is stored for 50 years after the verification and is carried into geologic repositories. 4.3 The result of LCIA The LCIA was calculated with LCI results described above. The result of LCIA for 1kWh of electricity is shown Fig. 3, where ‘a’ and ‘b’ show impacts in each impact category and percentage of impacts in each process respectively. For comparison, electricity by renewable energy such as photovoltaic (polycrystalline silicon), wind power and hydropower are included in this figure. FBR (Fast Breeder Reactor) is also included as next generation of power generating technology.

Fig. 2 System boundary for power generation plant. 4.2 LCI analysis Collected data by hearing for each typical type of present operating power plant is input materials (fuels, ammonia, sulfuric acid, hydrochloric acid, sodium hydroxide, etc.), output gases (CO2, NOx, SOx, PM, etc.), solid waste (dust, sludge, waste oils, construction waste and radioactive waste) and wastewater. The plant availability

The total impacts for 1 kWh of electricity in each power generation plant are, if that in crude oil fired plant is 1.00, 0.85 (coal fired), 0.83 (LNG fired), 0.69 (LNG CC), 1.79 (nuclear), 0.51 (MOX nuclear). As shown in the figure, the impact of coal fired power plant is 15 % as environmentally-friendly as that of oil fired plant and is almost equal to that of LNG fired plant. The reason is that proved reserve of coal is much larger than other fuels.

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Life C ycle Im pacts [N ETS/kW h]

4.5E-03 Fossil-fuel D epletion

4.0E-03

N atural-resources D epletion

3.5E-03

G lobal W arm ing

3.0E-03

O zone-layer D epletion W ater Pollution

2.5E-03

A ir Pollution

2.0E-03

R ain A cidification W aste Issues

1.5E-03 1.0E-03 5.0E-04

H ydropow er

N uclear (FB R )

W ind Pow er

Photovoltaic

N uclear (M O X)

LN G -C C

LN G Fired

C oal Fired

O il Fired

N uclear

0.0E+00

(a) for impact categories

80% 60% 40%

Fuel Procurem ent

C onstruction

O peration

H ydropow er

N uclear (FB R )

W ind Pow er

Photovoltaic

N uclear (M O X)

LN G -C C

LN G Fired

C oal Fired

O il Fired

20% 0% N uclear

Im pacts ratio

100%

W aste Treatm ent

(b) for respective processes Fig. 3 Life cycle impacts of power plants, per 1 kWh.

LNG needs combined cycle for impact reduction. As for nuclear power plant, it is necessary to reduce that impact by converting into MOX because of small reserves of Uranium. This is an effective way for Japan where almost fuels are imported on other countries. If FBR that utilizes 238 U included about 99% in natural uranium has been developed commercially, the impact would decrease at same level as renewable energy such as photovoltaic and wind power (Fig. 3 (a)). Hydropower has the biggest capacity for power generation and the smallest impact for 1 kWh among renewable energy but impacts on ecosystem or land use are needed to consider in the future because it occupies large area. As shown in Fig. 3 (b), the largest impact among whole processes is in power generation process where consumed fuels cause fossil fuels depletion and discharged gases cause global warming and rain acidification. The impacts of fuel production process in oil, coal and LNG fired plant occupy 10%, 12% and 17% of

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their impact respectively and they’re not small. It means the importance of environmental measures outside of Japan such as developments of effective transportation method and pre-treatment. The coal fired power plant need to reduce the impact for waste due to coal ash treatment (16% of its total impact). Coal gasification technology having high efficiency and less waste is expected to have the comparable impact with LNG-CC. 5. CONCLUSION Inventory data for 1MJ of fuels and 1 kWh of electricity are developed and applied to LCA-NETS developed in our laboratory as a new LCIA methodology. Environmental performance of the fuels, power plants and electricity are analyzed through their lifecycle from objective viewpoint based on LCA-NETS. As the result, we can show the factors that increase impacts in power generation and technology that decrease the impact in coal and nuclear power plant.

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ACKNOWLEDGMENTS We would like to express our sincere thanks to all who contributed to well cooperate in this research and also thanks to the Hitachi Scholarship Foundation for providing financial support. REFERENCES 1)

Investigation Report for LCA of Petroleum, LNG and Coal, Petroleum Energy Center, PEC-1998R-13, (1999) 2) Uchiyama, Y., Yamamoto, H., Energy Analysis on Power Generation Plants, Socio-economic Research Center, Y90015, (1991) 3) Hondo, H., Uchiyama, Y., Moriizumi, Y., Evaluation of Power Generation Technologies based on Life Cycle CO2 Emissions – Re-estimation using the latest data and Effects of the Difference of Conditions -, Socioeconomic Research Center, Y99009, (2003) 4) International Organization for Standardization (ISO) 14042, Environmental management – Life cycle assessment – Life cycle impact assessment 5) Ahbe, S., Braunschweig, A. and Mueller-Wenk, R., Method for Ecobalance (Methodik Fur Oekobikanzen), Buwal 133, (1990) 6) Miyazaki, N., et., Japan Environmental Policy Index (JEPIX) - Development of Eco-factor in Japan based on environmental policy and law - Japan Science and Technology Agency, (2003) 7) PRe Consultants http://www.pre.nl/ecoindicator99/default.htm 8) Jolliet, O., et., IMPACT 2002+: A New Life Cycle Impact Assessment Methodology, International Journal of LCA , Vol. 8(6), 324-330 (2003) 9) Steen, B., A Systematic Approach to Environmental Priority Strategies in Product Development (EPS), Version 2000 – General System Characteristics, Centre for Environmental Assessment of Products and Material Systems (CPM), (2000). 10) Itsubo, N., Inaba, A., A New LCIA Method: LIME has been completed, International Journal of LCA , Vol. 8(5), 305 (2003)

11) Research and Statistics Department Economic and Industrial Policy Bureau Ministry of Economy, Trade and Industry, Natural Resources and Fuel Department Agency for Natural Resources and Energy Ministry of Economy, Trade and Industry, Yearbook of Production, Supply and Demand of Petroleum, Coal and Coke, (Research Institute of Economy, Trade and Industry, (2002) 12) Investigation Report for LCI of Fuels for Transportation -Comparison analysis for conventional automobiles and fuel cell vehicles -, Petroleum Energy Center, PEC-2001L-04, (2002) 13) Kato, S., Maruyama, N., Kimura, Y., Anugerah, W., Kojima, Y., Jokaku, Y., Sadamichi, Y., Matsui, M., LCA of Industrial Products -Ecological Improvement by Reuse and Recycle of Vending Machines-, Proceedings of Symposium on Environmental Engineering, No.01-12, 421-425 (2001) 14) The Institute of Energy Economics, Japan, EDMC Handbook of Energy & Economic Statistics in Japan 2005, The Energy Data and Modeling Center 15) Hearing Investigation for CHUBU Electric Power Co., Inc 16) Hondo, H., Evaluation of Nuclear Power Generation Technologies based on Life Cycle CO2 Emissions, Socio-economic Research Center, Y01006, (2001) 17) Japan Coal Energy Center, www.ccuj.or.jp/ 18) Yamada, K., Komiyama, H., Photovoltaic Engineering, (Nikkei Business Publications, Inc.), (2002) 19) Nuclear Information Navigator, www.atomnavi.jp/

CONTACT Sate Sampattagul Chiang Mai University, Department of Mechanical Engineering, Faculty of Engineering, Muang, Chiang Mai, Thailand, [email protected]

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