Experiences with the estimation of CH 4 emissions from waste disposal in landfills Anke Herold

1. Experiences with the estimation of CH4 emissions from waste disposal in landfills Anke Herold Budapest, 9. Oktober 2006 VERTIC/REC Workshop: Fulfilling the monitoring and reporting requirements under the UNFCCC and Kyoto Protocol

2. Relevance Why do CH4 emissions from landfills matter? CH4 emissions from solid waste disposal sites are a key category for almost all Annex I Parties

3. Methods Estimating CH4 emissions from landfills 1996 IPCC Guidelines and IPCC GPG (2000) Tier 1 method: • Mass balance methodAssumption that all waste deposited in one year completely decays in the year of disposal. All degradable carbon is emitted as CH4 in the year of disposal. The method does not take into account the slower degradation process taking place in landfills Tier 2 method: • First-Order-Decay Method Takes into account delayed decomposition in landfills. Assumption that degradable carbon in waste decays to CH4 and CO2 following a first order decay reaction.

4. Impacts Impacts of methodological choice • The Tier 1 mass balance and the Tier 2 FOD method are significantly different with regard to the years in which the emissions are reported. • Tier 1 can result in higher base year emissions and lower emissions in actual years compared to Tier 2 as Tier 1 does not recognize actual emissions from waste disposed in the past. • In many countries waste amounts disposed in landfills decrease over time, this trend enhances the effect described above • If CH4 from solid waste disposal is a key category, IPCC GPG recommends using a Tier 2 FOD method • Expert review teams request Parties to use a FOD method

5. Challenges – time series Challenges of the Tier 2 method • FOD method requires data on waste amounts landfilled for a period of 3-5 half-lifes of biodegradable waste disposed in landfills which is back to 1950/1960 in temperate climates • No data available for such long time series • Historical data can be extrapolated backwards based on population and/or economic indicators, BUT • Considerable changes in waste generation and management practices over the same time period: • Strong increase in waste produced compared to 50s/60s • Larger share of population connected with waste collection services • New types of waste (plastic materials, packaging waste) that almost did not exist in the past • Legislation on landfills was put in place followed by collection of data which was further refined over the years

6. Challenges – time series Challenges of the Tier 2 method • Unmanaged landfills changed/ are changing to managed landfills • Separate collection of certain waste fractions introduced, recycling, composting • Incineration of waste in some countries became an important management practice • Backward extrapolation from recent years may not capture these changes, additional assumptions necessary

7. Challenges - composition Challenges of the Tier 2 method • Information on the composition of biodegradable waste to the following fractions is required for the application of the methodology: • Food; garden; wood and straw; paper; textiles; • sewage sludge • Industrial waste : Only some industries produce relevant amounts of biodegradable waste, waste amounts landfilled needed from these particular industries • Production of food, pulp and paper, wood, textiles, agricultural products, small share of construction waste • Composition may be highly country-specific and default composition provided in 2006 IPCC Guidelines may not be applicable for each country

8. Challenges – composition Waste composition changed over time, Example from Germany

9. Challenges – system change Example Germany Former GDR: • Waste generation per capita was much lower (190 kg/capita, year, almost 400 kg/capita in West-Germany) because less products, less packages • Refill systems, and effective collection systems for food waste, packages and plastics, paper driven by scarcity of resources in GDR • 1990 year of reunification: very high amounts of MSW landfilled because of replacement of many goods and first opportunity to buy many products. At the same time breakdown of previous collection systems • Household waste in GDR only 16% of total MSW disposed on landfills. • High share of ashes and minerals in MSW and in landfill disposals from households

10. Challenges – system change Example Germany

11. Challenges – CH4 recovery CH4 recovery • CH4 recovery and use for energy purposes is increasing • CH4 recovered is subtracted from the CH4 generated and the resulting difference is reported as CH4 emissions in the GHG inventory • IPCC Guidelines require monitored data on the amounts of CH4 captured and flared or used for energy purposes • Not extremely challenging for small countries with a limited number of landfills with CH4 recovery • Big challenge for big countries with several hundred landfills with CH4 recovery • Similar monitoring requirement under EU Landfill Directive • CH4 recovery and use continues after landfills are closed, but statistical surveys may only capture active landfills

12. Challenges – CH4 recovery CH4 recovery • Recovery efficiency reported varies between 10-85% • Most measurements on closed landfills, easier to recover • Difficult to recover CH4 from unfinished parts of operating landfills • Dutch measurement results: Recovery efficiency is considerable different between active and closed landfills (20% compared to 50%) • New 2006 IPCC Guidelines default value of 20% takes into account that there are escapes from operating parts of landfills

13. Challenges – CH4 recovery CH4 recovery • Flares: installed flare capacity does not provide reliable information on the amounts of landfill gas flared: • Overdesigned equipment • No continuous operation • Some flares are backup flares for the situation when the gas-engine is not operating

14. Other data requirements Additional data requirements • DOC (degradable organic carbon) for different fractions – IPCC default parameters available, no dramatic variations compared with country-specific values • Methane generation constant: IPCC default available depending on climate • Oxidation factor: IPCC default available – high uncertainty, measurement difficult, therefore difficult to develop CS factor, almost all countries use default • Differences between managed and unmanaged landfills: captured with default MCF (methane correction factor), only assumption on share of managed/ unmanaged landfills necessary and calculation of weighted average

15. Perspectives Recent developments • IPCC 2006 Guidelines replace the Tier 1 mass balance method with a Tier 1 FOD spreadsheet model with step-by-step guidance and improved default data (edited version of report will be available soon from IPCC homepage) • Implementation of Tier 2 is much easier because only the default model has to be linked with activity data for a country • EEA and DG Environment conducted an expert meeting for EEA member countries with the aim to estimate CH4 emissions from solid waste disposal with the IPCC FOD spreadsheet model and IPCC default data for all MS that did not yet use a FOD method (some other MS participated to used the IPCC default model as verification tool).

16. Perspectives Workshop results • IPCC FOD model is straightforward and easy to understand and to apply. Even Non-inventory experts managed to estimate a FOD approach for their country based on country-specific data during the 2-days meeting • IPCC FOD model is also a useful tool for verification purposes • Definition of municipal solid waste (MSW) is important (inclusion of construction waste) • Incorporation of industrial waste • When industrial waste landfilled cannot be disaggregated to the relevant industry branches, it is better not to include industrial waste in the estimation, because this would result in a large overestimation of emissions.

17. Perspectives Workshop results • Discussion of historic waste composition: much smaller share of biodegradable waste landfilled than today • Wood and paper was burned in stoves and fireplaces in households • Food waste was fed to animals/ composted in rural areas • Garden waste was composted or burnt • Textiles were re-used • Sewage sludge: wastewater was not collected centrally and sewage sludge was not disposed on landfills • Much more inert materials like ashes in household waste

18. Perspectives Workshop results • The IPCC FOD model allows to estimate different scenarios, e.g. varying the assumptions on waste amounts and composition for historic years • effects of changes and sensitivities become clearer • Variations of the amounts of biodegradable waste landfilled in early years of the time series did not have strong impacts on recent emissions, thus the uncertainty of the backward extrapolation did not have a very strong impact on the results for the actual years. • With the support of the model and with some assumptions based on historic experiences, the Tier 2 FOD estimation could be implemented, even in countries that did not have long time series of waste data

19. Thank you for your attention! Documents of the Workshop available at http://air-climate.eionet.europa.eu/meetings/past_html