Homes and public buildings across the borough of Hounslow are set to receive low-carbon heating thanks to a pioneering project that will recover energy from treated waste water at Thames Water’s Mogden Sewage Treatment Works.

Heat Network Route Map

With waste water from around 2 million people processed at Mogden each day, the site will supply renewable heat to the first phase of the Hounslow Heat Network, a landmark moment in the borough's decarbonisation journey.

Hounslow Borough Council has secured £10.55 million in Government funding from the Green Heat Network Fund (GHNF) to support the project.

The phase one network has the potential to supply heat to up to 3,000 homes, as well as hospitals and NHS buildings, libraries, schools, commercial premises and other public buildings across the borough. Heat will be distributed through approximately 8.8km of underground pipes, providing clean, reliable heating without the need for individual boilers or electric heaters.

Initial construction is expected to begin in 2028. Once operational, the scheme is projected to deliver 50GWh of low carbon heat each year, reducing annual emissions by around 6,690 tonnes of CO₂e - equivalent to removing more than 3,800 petrol cars from the road.

Thames Water is one of the UK’s largest producers of renewable energy from waste. In 2024/25, the company generated 475.3GWh of renewable energy, meeting 25.8% of its total energy needs. Across London and the Thames Valley, up to 10TWh of low carbon heat could be recovered from waste water - enough to heat more than 800,000 homes, highlighting the huge, untapped potential of this technology.

Dejan Vernon, Energy Technical Manager at Thames Water said:

“Our purpose is to deliver life’s essential service, and the heat recovery scheme at Mogden sewage treatment works will deliver real benefits for the Hounslow community.

“By capturing heat from wastewater, we can help provide low-carbon heating for public buildings, homes and essential services across the borough, demonstrating how the water sector can support the transition to net zero while delivering for customers and the environment.”

Heat networks supply energy from a central source via insulated underground pipes carrying hot water, offering a highly efficient alternative to traditional heating systems. While wastewater heat recovery is relatively new in the UK, more than 500 sites worldwide already use the technology, particularly in Northern Europe and Scandinavia where heat networks are well established.