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GHG emissions from landfills for EPER reportingIan Whitwell
Pollution Inventory team
Environment Agency of England & Wales
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: CH4, CO2, N2O, CFCs etc
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.uk Currently use non-mandatory
GasSim conceptual model
GasSimLite
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 50th percentile Validation studies
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
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
Waste inputs
Gas plant Specify gas
engines and flares
Turndown ratios Gas collection
efficiency Air-fuel ratios Destruction
efficiency
Use in practice
Nearly all UK IPPC landfills now report CH4, CO2 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
Potential benefits for GHG reporting Site specific data: ‘bottom up’ data should
provide better national estimates Emissions data available for other GHGs if
required: CO2, CFCs etc Approach consistent with IPCC Tier 2
methodology for CH4
CH4 emission estimates for UK landfills
Note:
- PI includes emissions for England & Wales only
- EPER includes England, Wales, Scotland and Northern Ireland
* no QA
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 CH4
estimates