asked the Secretary of State for the Environment what percen- tage of energy used for all domestic and industrial purposes is currently derived from sewage; what steps are being taken to increase such energy utilisation; and if he will make a statement.

Detailed figures are not available. Methane gas is widely produced at sewage works as part of the sludge treatment process. The gas is employed to power plant and machinery at sewage works, but there is no surplus for other purposes. I am sure that water authorities need no encouragement to ensure that gas is both produced and used with maximum efficiency.