1. GHG emissions from landfills for EPER reporting Ian Whitwell Pollution Inventory team Environment Agency of England & Wales

2. EPER reporting process PPC regulations from IPPC Legal Notice: report annual mass emissions to national inventories: England/Wales: Pollution Inventory Scotland: Scottish Pollutant Release Inventory Northern Ireland EA collects/extracts required data for EPER submission - 2002 emissions data submitted Landfills, incinerators most relevant operations Relevant GHGs: CH 4, CO 2, N 2 O, CFCs etc

3. Landfills New to Inventory reporting Decision to provide a reporting tool. Ease of use important Landfill risk assessment tool being developed for use in permitting landfills: GasSim Use source term as basis for Inventory reporting: GasSimLite Freely available from www.gassim.co.ukwww.gassim.co.uk Currently use non-mandatory

4. GasSim conceptual model GasSimLite

5. Principles The scientific principles implemented in GasSim also underpin the 2002 revisions to the UK National Assessment Model (Bob Gregory will describe more tomorrow) GasSim is a probabilistic model Parameter uncertainty expressed as pdf Output for Inventory reporting is 50 th percentile Validation studies

6. The Source term Gas generation module primarily considers: Infiltration Waste mass and breakdown, e.g. % domestic, industrial, etc Waste composition and biodegradability Waste degradation rates Water balance Landfill engineering design Emissions module considers: Gas engines and flares Methane oxidation in the cap (IPCC or fracture model) Surface emissions Lateral emissions

7. Landfill engineering Four types of cap are available Seven types of basal liner design are available IPCC default approach for methane oxidation A mechanistic model of methane oxidation is available

8. Waste inputs

9. Gas plant Specify gas engines and flares Turndown ratios Gas collection efficiency Air-fuel ratios Destruction efficiency

10. Use in practice Nearly all UK IPPC landfills now report CH 4, CO 2 and other GHGs using GasSim(Lite) In general default values are used Some concerns from operators in defining historical waste inputs First used for 2002 emissions reporting Experience suggests 2-3 yrs until reliable use

11. Potential benefits for GHG reporting Site specific data: bottom up data should provide better national estimates Emissions data available for other GHGs if required: CO 2, CFCs etc Approach consistent with IPCC Tier 2 methodology for CH 4

12. CH 4 emission estimates for UK landfills Note: - PI includes emissions for England & Wales only - EPER includes England, Wales, Scotland and Northern Ireland * no QA

13. Future options More feedback on use of GasSimLite by landfill operators. Verification process Understand reasons for differences between bottom-up (EPER) and top-down (IPCC) national estimates Include uncertainty Consider use of EPER data for national CH 4 estimates