Thames Water has rolled out biomethane conversion technology to two sewage treatment works to convert sludge into energy capable of powering 2,100 homes.
The company worked with UK Power Networks to upgrade the network capacity for the project. This included increasing the export limit to enable the converted wastewater to be used as an energy source in homes and businesses.
The Hogsmill sewage plant in Surrey and the Beddington works in Sutton will produce and export enough electricity to the grid to power 900 and 1,200 homes respectively.
“We are thrilled to introduce poo power as a source of energy from two sites in south west London as we look to play a role in the future of renewable energy,” Ian Ruffell, Thames’ head of wastewater treatment for South London, said.
“The successful use of biomethane conversion at Hogsmill and Beddington shows the dedication of our teams to delivering this project and our own commitment towards reducing our carbon footprint.”
The process heats the liquid separated from solids in the sludge at the end of the wastewater treatment process. This creates biomethane, which can be used to power engines connected to electricity generators.
The power is used on-site to offset the energy used to process and treat wastewater, with the leftover power exported to the grid.
The company first used the process at its Deephams plant in north London and began upgrades to its Mogden site in the south of the capital in January this year to generate power from methane.
Each day, Thames collects and treats 4.6 billion litres of wastewater from around 16 million people. In 2022/23 it self-generated 536 GWh of renewable energy, which was equivalent to 27% of its own consumption.
Capturing and using emissions methane from wastewater treatment is one way that sewerage companies can lower the emissions from their activities as part of the sector-wide commitment to reach net zero ahead of UK government targets.