Centrica Starts Supplying Natural Gas From Sewage to U.K. Homes

Centrica Plc will begin feeding biomethane gas from sewage into the U.K.’s natural gas network today, as the country’s biggest energy supplier seeks to trim carbon emissions.

The project will supply enough gas for 200 homes using anaerobic digestion to treat waste from Thames Water Ltd. customers, Centrica said in a statement today. The biogas produced is then cleaned to remove any odor and fed directly into the gas network.

Biomethane could account for about 15 percent of the British domestic gas market by 2020, Centrica said, citing National Grid Plc statistics. The U.K. consumed 86.5 billion cubic meters of natural gas in 2009, according to BP Plc’s statistical review. Over 50 percent of the country’s gas is imported from Norway, Qatar and mainland Europe.

“Biogas has exactly the same emissions as regular gas, but it’s renewable so we’re not depleting fossil fuel resources and we’re not taking the gas from other countries,” said Martin Orrill, project manager at the Didcot Renewable Gas Project.

The technology to upgrade biogas to grid standards is relatively new and uneconomic without feed in tariffs, Bloomberg New Energy Finance analyst Irmgard Herold said in an interview. About 30 biogas-injection plants already exist in Germany and an additional 40 are under development, she added.

The British government is considering adopting a renewable heat incentive to subsidize the development of technologies including biomass boilers and biomethane-to-grid projects. A payment of 5 pence to 7 pence a kilowatt hour for gas from renewable sources would be the “right amount” to boost investment in the technology, Orrill said.

The average person produces about 30 kilograms (66 pounds) a year of waste suitable for producing biomethane. This means Britain’s 62.5 million people could generate enough renewable gas to meet the annual demand of about 200,000 homes, Centrica said. The Windsor, England-based utility and its partners spent six months and about 2.5 million pounds developing the Didcot project.

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