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Biomass and Bioenergy

Biomass and Bioenergy. Approaches to Assessing Greenhouse Gas Mitigation Potential Carly Green. IEA Bioenergy Task 38 National Meeting - Ireland. 20 November 2003. University College Dublin. Introduction. What is biomass? Why calculate GHG benefits The Carbon Cycle Options for biomass

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Biomass and Bioenergy

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  1. Biomass and Bioenergy Approaches to Assessing Greenhouse Gas Mitigation Potential Carly Green IEA Bioenergy Task 38 National Meeting - Ireland 20 November 2003 University College Dublin

  2. Introduction • What is biomass? • Why calculate GHG benefits • The Carbon Cycle • Options for biomass • How are GHG benefits calculated • Life Cycle Analysis • Case Studies

  3. What is biomass? • Accumulates in living vegetation following photosynthesis • Important pool in the carbon cycle • Exists in many forms • Contributes to other pools within the global system

  4. Contribution Emitted (source) Absorbed (sink) Burning fossil fuels 6.3 Land use change 1.6 Enhanced vegetation growth 3.0 Ocean-atmosphere exchange 1.7 Total 7.9 4.7 Balance 3.2 The Carbon Budget (Source: Broadmeadow and Matthews, 2003)

  5. Greenhouse gas mitigation options • Fuel for Energy • Dedicated Sources (i.e. by-products of other activities) • Dependant Sources (i.e. energy crops grown specifically for food) • Carbon Sink • Wood Products

  6. Fuel for Energy • Long use history (i.e. centuries) • Currently contributes 14% to the global energy requirements • More efficient use through modern technology • Solid liquid and gas • Capable of replacing all fossil fuel energy forms

  7. Fuel for Energy (cont.) a. CO2 captured by growing crops and forests b.O2 released and C is stored in the biomass of plants c.C in harvested biomass is transported to the power station d.Released C from burning biomass is made available again. ‘Recycling of carbon’ Source: IEA Bioenergy Task 38

  8. Carbon Sink • Recent Policy has focused on this option • Kyoto Protocol Article 3.3 • Increase carbon stock in various pools • Aboveground / belowground and soil • Time Dependant • Land use change

  9. Managed as a carbon sink a. Establishment b. Full vigour c. Mature Phase d. Longterm equilibrium Managed as commercial forest Periodic felling indicated by arrows Over several rotations carbon stocks niether increase of decrease Accumulation balanced by removals for wood products, bioenergy etc Carbon Stock Dynamics

  10. Wood Products • Product replacement • Sink • Fuel at end of life

  11. Why calculate GHG benefits • Analyse potential • Quantify benefits • Compare options • Quality decision

  12. Life cycle analysis considerations • Carbon stock dynamics • Trade-offs and synergies • Leakage • Permanence • Emissions factors • By-products • Efficiency • Upstream/downstream emissions Task 38 standard methodology for calculating GHG emissions Source: IEA Bioenergy Task 38 • Other greenhouse gases

  13. Constraints Must compare systems within same system boundary • Information (data) sources • Boundary selection • Restricted analysis Task 38 standard methodology for calculating GHG emissions Source: IEA Bioenergy Task 38

  14. Bioenergy Case Study 1 GORCAM output Source: IEA Task 38

  15. Bioenergy Case Study 2a Ethanol production in Brazil vs United States Potential CO2 emissions avoided • Brazil 5.6 MtC/yr • United States 0.59 MtC/yr • Source: Kheshgi and Marland, 2000

  16. Bioenergy • Bioenergy output to fossil energy input • Forestry and agriculture (25-50 : 1) • Liquid energy (4-5 : 1) Source: Marland, 1999

  17. 0,62 natural gas power plant with gas and steam turbine N2O 16,4 wood chips power plant with steam turbine 44,9 CH4 Greenhouse gas 0,307 413 CO2 34,5 459 CO2-eq 51,1 0 100 200 300 400 500 Greenhouse gas emission factor [g CO2-eq. kWh electricity-1] Bioenergy Case Study 2b Austria: Fuel cycle analysis of Power plants Source: Jungmeier et al, 1999

  18. Sink Source Canada: Total Forest Ecosystem Carbon Modelling (1920 - 1995) Case Studies - Sink Source: Kurz and Apps, 1999

  19. Case Study - Sink Typical radiata pine regime New Zealand:Long-term average carbon density Source: IEA Task 38, 2003

  20. Case Study – Wood Products • 1 kilometre of transmission line • Life 60 years • Including disposal Product Replacement Emission in tonnes of CO2 equivalent to construct Source: Matthews and Robertson, 2002

  21. Case Study – Wood Products Canada:Forest Products Carbon Storage Source: IEA Task 38, 2003

  22. Preferential Use Source: Matthews and Robertson, 2002

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