§ Mr. Sheerman
To ask the Secretary of State for the Environment what assessment he has made of the proportion of methane produced at landfill sites that can be captured for energy conversion over the entire period that methane will be produced. 
§ Mr. Clappison
The quantity of methane gas which can be collected from a landfill site over its lifetime depends on a wide range of site specific details. However, for the purpose of investigations into landfill gas emissions, a gas extraction efficiency of 70 per cent. over the lifetime of the waste has been assumed. This is based on available published information resulting from field studies.
It is further estimated that, in 1994, 28 per cent. of extracted methane was burnt in landfill gas energy recovery schemes the remainder being flared.460W