Life cycle assessment of bioenergy

Transcription

1 EPROBIO Intensive program Foggia, July 2012 Life cycle assessment of bioenergy Wouter Achten & Joana Almeida KU Leuven, Belgium

2 Content Revisit general methodology Methodology issues in LCA of bioenergy systems Example: Oil palm biodiesel Literature examples/overview: Biodiesels Bioethanol Biogas

3 LCA Method Goal and scope Inventory Interpretation Conclusions Recommendations Product/system improvement Policy making Impact assessment

4 Goal and Scope Funtional unit Impact category System boundaries Reference system Allocation

5 Functional unit - bioenergy Input unit related: Mass or energy of input biomass Independant from conversion processes and type of end-use Allows comparing the best use for a given feedstock Output unit related: Unit of heat, power or distance transport Allows comparison of the provision of a certain service from different feedstocks Unit of agricultural land Hectares Year Used in characterized by multiple final products It allows avoiding an allocation 10% 70% 15% 5% Cherebuni & Stromman, Bioresource Technology, 2011

6 Functional unit - bioenergy Global warming potential of electricity production from short rotation coppice , ,12 ton CO2-eq./ha/100jr fk wilg Miscanthus hakhout ton CO2-eq./GJprod 0,1 0,08 0,06 0,04 0, emissie productsysteem (per ha) emissie referentiesysteem (per ha) vermeden broeikasgasemissie (per ha) 0 vermeden broeikasgasemissie (per geproduceerde GJ) Lettens et al., Biomass & Bioneregy, 2003 Performance on a ha basis (figure left) differs from the one on an energetic basis Show result using different functional units? Which question do you want to answer?

7 Impact category - bioenergy Energy balance 8% GHG balance Energy + GHG balance > Energy + GHG balance 18% 23% 50%

8 Impact category - bioenergy Achten et al., Applied Energy, 2010

9 System boundaries - bioenergy Cradle-to-grave (well-to-wheel): Biomass production Processing and transport Use phase (end of life) is important Waste Important direct emissions: N 2 O field emissions 1-5% of N fertilizer application = 298 CO 2 eq CO 2 final combustion of bioenergy (Winter 2011)

10 System boundaries - bioenergy Land use change 23% Direct Indirect LCA limitation: Static Arbitrary amortization period (20 year in EU directive) Discounting LCA in timesteps Carbon debt

11 Carbon debt GHG emissions Fossil Biodiesel Biodiesel Fossil Carbon debt (CO 2 eq per ha) Land LCA use change: Biodiesel clearing system land reduces GHG emissions soil emissions compared to fossil CO 2 diesel Repayment time (yr) (Adapted from Vandenbempt 2008, Thanks!) x y Time

12 dluc - Carbon debt LCA results Fargione et al Science

13 iluc Direct land use change Indirect land use change (dluc) (iluc) Land use change towards bioenergy crops can trigger a land use change else where in the world (eg. deforestation) eg. US switch to Corn triggered Deforestation in Brazil

14 iluc US boeren: maize &soy maize & maize US: soy-export Price Soy Global: Soy cultivation-intensity Deforestation in Brazil for soy Process emissions Who is responsible? + indirect Process emissions + indirect LUC emissions

15 dluc & iluc Carbon debt Brazil Lapola et al PNAS

16 dluc & iluc Carbon debt Brazil Lapola et al PNAS

17 Reference system - bioenergy Fossil reference system 75% Other biofuel system as reference 12% No reference system 13% Cherebuni & Stromman, Bioresource Technology, 2011

18 Allocation - bioenergy Allocation by ratio Mass Energy Economic EU 48% 11% 20% 17% Avoiding allocation System boundary expansion PAS2050, ISO Choice of functional unit (area, input related) 31% 25% 6% Ignored 7% Unknown 11%

19 LCA Method Goal and scope Inventory Interpretation Conclusions Recommendations Product/system improvement Policy making Impact assessment

20 Examples Biodiesel from Oil palm in Cameroon

21 Oil palm biodiesel Goal & Scope Functional unit: 100 km driven with Oil palm biodiesel Achten et al., ES&T, 2010

22 Oil palm biodiesel Goal & Scope Achten et al., ES&T, 2010

23 Oil palm biodiesel Inventory Foreground: On site data collection Expert interviews Field measurements Field emissions: IPCC default data Background data: literature & databases

24 Oil palm biodiesel Impact assessment Achten et al., ES&T, 2010

25 Fossil energy use Achten et al., ES&T, 2010 Reduction: 45% 25

26 Global warming potential Achten et al., ES&T, 2010 Reduction: 77% 26

27 Acidification Achten et al., ES&T, 2010 Reduction: 13% 27

28 Eutrophication Achten et al., ES&T, 2010 Increase: 35% NOx from Biodiesel Combustion 28

29 Scenarios Achten et al., ES&T, 2010 Waste water scenarios Agricultural land Cultivation 1. Dumped (case study) (M.I) Fresh Fruit Bunches Extraction Crude Palm Oil POME 2. In ponds without CH 4 recovery (M.II) Refinery Stearin Transesterification 3. In ponds with CH 4 recovery (biogas) (M.III) Biodiesel Engine combustion

30 Achten et al., ES&T, 2010 Oil palm system Cultivation System boundary expansion By-products Substitution Reference system Extraction FFB Extraction CPO POME Refinery Stearin Transesterification PKO PKO PKM PKM M.III: biogas from POME Olein FFA PKO + AE PKM PKO + AE local animal PKM + feed local FRef animal II: feed natural gas CPO Crude oil Processing Diesel Distribution and storage Diesel Glycerine Glycerine Engine combustion Engine combustion 30

31 Fossil energy use Achten et al., ES&T, 2010

32 Global warming potential Achten et al., ES&T, 2010

33 Acidification Achten et al., ES&T, 2010

34 Eutrophication Achten et al., ES&T, 2010

35 Carbon debt Vandebempt, 2009

36 - FU: 1 MJ diesel - well-to-wheel - IC s: Abiotic depletion, Global warming potential, Ozone depletion, photochemical oxidation, acidification, eutrophication, human toxicity, fresh water aquatic ecotoxicity, marine aquatic ecotoxicity, Terrestric ecotoxicity - Allocation: mass ratio - Impact assessment: CML 2001

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39 Soybean

40 Jatropha

41 Micro algae

42 Single score

43 Sensitivity to allocation

44 - Reviews 47 papers - FU: area based

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50 - FU: MJ fuel - well-to-wheel - IC s: energy & global warming - Allocation: energy, mass, value ratio and avoided allocation

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55 Learning goals General Methodology Points of attention for LCA in biofuels General LCA impacts of biofuels.

56 Wouter Achten Joana Almeida