4 Activity data, emission factors and combined uncertainties (6.A)
5 6.A Solid Waste Disposal: parameters effecting key uncertainties Quantity and composition of landfilled waste –waste composition may change over time –actual emission estimates are still dependent on data extrapolations from earlier years which are in general of lower quality –Data of industrial waste is often of lower quality Quantity of CH 4 that is actually generated –Small changes in the assumed DOC value can result in large variations. –DOC values are widely differing among Member States (as different waste compositions) –DOCf –Assumed half-life or k (methan generation rate konstant) Quantity of CH 4 that is actually emitted –Degree of oxidation that occurs as the gas diffuses through the landfill cover materia (presence, thickness and other characteristics of SWDS cover material). –Methane recovery
6 6.B Default uncertainties according to IPCC GPG: Activity data (6.B.1): –Industrial production+- 25% expert judgement needed –COD/ t productvery uncertain – 50%, 100% Activity data (6.B.2): –Human population+- 5% –BOD/ person+- 30% Emission factor: –Maximum CH 4 Producing Capacity Bo+- 30% –Fraction treated anaerobicallyexpert judgement needed
7 Uncertainties regarding activity data CRF 6.B Wastewater Handling 1)Sparsely populated areas 2)Densely populated areas
8 Uncertainties regarding emission factors CRF 6.B Wastewater Handling 1)Sparsely populated areas 2)Densely populated areas
9 Activity data, emission factors and combined uncertainties (6.B) 1)Sparsely populated areas 2)Densely populated areas
10 6.B Wastewater handling: parameters effecting key uncertainties Organic waste water quantity and composition –Often amount of DOC in the wasteater that is produced and the volumes handled in the various systems are often not well known. –DOC values in industrial sector are often averages from several processes. Wastewater handling facility efficiency and output –Aerobically treated wastewater by handling plants may be subject to anaerobic conditions due to poorly managed and functioning facilities. –Efficiency of CH 4 recovery / flaring –Data on lagoons are very limited.
11 Determination of Uncertainties for EU inventory depending on correlation between the MS uncertainties Relative uncertainties if it is assumed that they are –not correlated: 14.3 % (6.A); 30.3 % (6.B) –correlated: 41.8 % (6.A); 63.5 % (6.B) Assumption made: –Uncertainties of Member States correlate if either Default EF or T1 as method were applied.
12 How to improve uncertainty estimates? Each Member States should check uncertainties relative to IPCC default values. Improvement of data quality regarding parameters affecting key uncertainties. Let us discuss...