In terms of renewable energy, this might just be the most natural kind of gas there is.
“Processed poo” — or broken down sewage — is being turned into methane gas and helping power homes in the Birmingham area of England, according to a Bloomberg report this week. The process, the report said, promises to help thousands of U.K. residents become able to turn on their stoves and cook dinner with a cost-saving renewable fuel produced from their own human waste.
“Although it’s a little unsavory, there’s lots and lots of power locked in poo,” Simon Farris, the renewable energy development manager for a company called Severt Trent, told Bloomberg in a statement. “And when that’s processed it’s perfect to generate clean renewable green gas.”
Bloomberg’s report focuses on Severn Trent, Britain’s second-largest publicly traded water company, which is producing what’s known as “biomethane,” a natural gas imitation made by treating sewage and breaking it down. The company’s $13.6 million Minworth water treatment plant has long treated the sewage from approximately 2.5 million people and made biomethane out of it. And the process isn’t unique to the U.K. — Washington’s D.C. Water treatment plant is converting poo to power in order to fuel 11,000 homes in the D.C., Maryland and Virginia area.
But in the U.K., biomethane gas produced from wastewater plants was previously only used to power the plant itself, the Bloomberg report said. Last week, Severn Trent became the first sewage treatment plant in the U.K. to make bio-methane power available to the public, injecting the biomethane into the electric grid. Water treatment firms Wessex Water and Northumbrian Water are preparing to supply biomethane gas from their sewage treatment plants into the electric grid as well, a report from the U.K. Independent notes.
CREDIT: European Biogas Association
Biomethane is upgraded biogas from anaerobic digestion, a process currently used on more than 200 U.S. farms to convert manure into biogas. The normal biogas produced from anaerobic digestion is comprised of about 60 percent methane and 40 percent carbon dioxide. Biomethane is an upgraded version of biogas that can be injected and distributed through the natural gas grid, and can be used in vehicles the same way as natural gas, according to the Sustainable Energy Authority of Ireland.
In terms of greenhouse gas emissions, Western Washington University researchers estimate an engine powered with bio-methane emits about 95 percent less carbon than a traditionally fueled engine. The combustion of biomethane releases some biogenic carbon, but many consider that irrelevant because those emissions are the same amount as those that would be emitted during the natural decomposition of the waste. The European Biogas Association estimates that replacing diesel fuel and gasoline use with biomethane produced from organic waste — such as the operations in Birmingham — could reduce carbon emissions from those sources by up to 96 percent.
Farris said the gas produced by Severn Trent will be enough to meet its own energy needs, thereby allowing the company to cut its carbon emission by 300,000 metric tons, the emissions reduction equivalent of taking about 63,000 cars off the road.