Life cycle GHG emissions of biofuels: Results from review of studies

1. Life cycle GHG emissions of biofuels: Results from review of studies Emanuela Menichetti UNEP-DTIE, Energy Branch European Environment Agency Expert workshop Copenhagen, 10 June 2008

2. UNEP’s Activities on Bioenergy • Bioenergy Strategy developed in 2007 • UN Energy report on Bioenergy • Most relevant current activities • GBEP => UNEP entrusted with developing sustainability work stream • RSB => UNEP is a Steering Board Member and participates in all 4 technical working groups • Jatropha Roundtable => network of centres of excellence to share information on agronomics, sustainability criteria, technologies and business models

3. Life cycle GHG emissions of biofuels • Two main review studies • Chapter on LCA for the OECD MCM report in cooperation with the IEA • Report for the International Panel for Sustainable Resource Management

4. Overview • Review and analysis of 60 studies • Full LCA studies: 32% • Energy and GHG emission balances: 33% • Methodological / review studies: 23% • Life cycle inventories: 7% • Energy balances: 5% • Focus mostly on transport applications

5. Selected results for GHG (w/o LUC)

6. Key determinants of results (w/o LUC) • Two main life cycle stages – and within these two – a limited number of variables are responsible for the largest impact share • Agricultural phase • N2O balance • Assumptions on co-products (and allocation) • Transformation phase • Process energy • Assumptions on co-products (and allocation)

7. Example: rapeseed biodiesel Green: quite consistent background assumptions Orange: some discrepancies observed, it affects results to some extent Red: high inconsistency area, it affects results significantly Overall GHG improvement on biodiesel : Ecobilan 80% vs. EMPA 23%-41%

8. Allocation methods QUESTIONS: • What is the most appropriate allocation method for biofuel co-products for regulation purposes? • One method for whole life cycle or mixed approach? • Consistency with allocation method(s) in fossil fuel chains?

9. Influence of process energy • Quantity and type of energy source significantly affect LCA results • QUESTION: What should be used for regulation purposes? • Present average mix, state-of-the art, BAT, expected trends? • Wide range of specific process energy consumption observed in reviewed studies (e.g. Unnasch and Pont, 2007) • State-of-the art vs. old plants (e.g. Wang et al. 2007)

10. Other methodological aspects • Various (and non harmonised) LCI databases • Various LCIA methods used • Most studies only cover CO2, N2O and CH4 • Various reference scenarios modelled • Uncertainty related to the fossil fuel chain: • Variability in assumptions and results of fossil fuel chains • Lack of updated LCA of marginal fossil fuel production (deep extraction, unconventional oils) • Comparison with average or marginal fossil fuels?

11. Land use change • Very significant impacts on overall GHG balances • Direct land use change can be integrated in LCA • Harmonization on data and methods needed • More research needed to include indirect land use change • What is the reference baseline? • How to take productivity and process improvements into account?

12. Conclusions • Research gaps • Need for more full LCA studies on other crops and geographical contexts • Number of open questions • N2O emission factors • Allocation methods • Consistency of fossil fuel chain LCA • Level of technology representativeness for policy-making decisions • Direct and indirect land use change • Parametric LCA? • To better evaluate the influence of assumptions • To depict future improvements • To orientate policy making • Harmonisation of rules • GBEP, RSB, UNEP LCI, EPLCA • Look at experience in the eco-labelling sector (PCR-like process)

13. Division of Technology, Industry and Economics Energy Branch 15 rue de Milan, 75009 Paris France tel. : +33.1.44.37.30.07 fax. : +33.1.44.37.14. 74 e-mail: emanuela.menichetti@unep.fr www.uneptie.fr/energy