Sewage could be used to heat half the homes in Britain

Up to half the UK's homes could be heated with gas made from waste food or sewage, according to research by the National Grid.

Last Updated: 8:04AM GMT 02 Feb 2009

The analysis suggested biodegradable waste could be used to make biomethane to be injected into the gas grid, which would help achieve targets to source 15 per cent of all energy from renewables by 2020.
The study by Ernst and Young for National Grid also said that in the longer term, biogas could be used to provide up to half the country's domestic gas heating.
Currently a small amount of biogas is produced from landfill and sewage plants but is burnt to produce electricity, and National Grid believes piping the gas to homes would be more efficient.
The study said the £10 billion costs of delivering renewable gas compares reasonably with the provision of other types of renewables, such as wind power, and the unit cost of the gas would be similar to other "green" energy sources.
It would also provide the country with greater energy security to use waste products generated in the UK to provide gas as North Sea supplies of natural gas tail off.
Biogas, which is already being produced and injected into gas grids in Europe, is made through anaerobic digestion of wet waste such as sewage or manure, or through gasification of drier waste or energy crops.
Janine Freeman, head of National Grid's sustainable gas group, said: "Biogas has tremendous potential for delivering large scale renewable heat for the UK but it will require Government commitment to a comprehensive waste policy and the right commercial incentives.
"Biogas has benefits on so many fronts," she went on.
"It is renewable and could help to meet the target of 15 per cent of all our energy coming from renewable sources by 2020.
"It provides a solution for what to do with our waste with the decline in landfill capacity and it would help the UK with a secure supply of gas as North Sea sources run down."
The report said there would be no insurmountable technical difficulties in delivering biogas, and with an extensive gas grid in the UK there would be little need for major new infrastructure development.
National Grid said the main hurdle would involve getting commercial incentives for waste to be turned into biomethane for injection into the gas grid rather than electricity.
A spokeswoman for the Department of Energy and Climate Change said: "Government set out its policies on recovering energy from waste in its Waste Strategy 2007.
"Further work is taking place in the context of our Renewable Energy Strategy to establish what potential might exist for biogas injection to the gas grid."