The London Borough of Hounslow has initiated preliminary market engagement for the development of a borough-wide low-carbon district heating network in west London. The project, known as the Hounslow Heat Network, is estimated to be worth £500 million (US$673.5 million) and aims to modernise the borough’s heating infrastructure while improving energy resilience and reducing carbon emissions. Following Cabinet approval in December 2025, the council intends to appoint a Heat Network Development Partner (HNDP) to finance, develop and deliver the scheme through a joint venture arrangement in which the council will retain a Golden Share.

The proposed network will be delivered in phases, beginning with an initial scheme that will recover waste heat from Thames Water’s Mogden Waste Water Treatment Works. The recovered heat will be distributed through underground district heating pipes to major customers, including West Middlesex University Hospital, new-build developments and council-owned properties. The initial reference scheme is expected to cover approximately 9.57 km of network infrastructure and deliver an annual heat demand of 45 GWh. At full build-out, the network is anticipated to extend to approximately 69 km and supply around 484 GWh of heat annually, with the potential to serve residential, commercial and public-sector buildings across the borough.

The appointed development partner is expected to bring expertise in heat-network financing, engineering, construction, operation and maintenance, alongside the ability to provide investment and delivery capability. The project will involve heat-recovery systems, heat pumps, district heating mains, heating plants, heat-transfer stations and associated mechanical and electrical infrastructure. The council has secured approximately £10.55 million in funding from the Green Heat Network Fund to support the first phase. 

The contracting authority is conducting a two-stage preliminary market engagement process to gather feedback from prospective developers, investors, infrastructure operators and supply-chain organisations before launching the formal procurement. The first stage will include an online webinar scheduled for 18 November 2026, followed by a second stage expected in February or March 2027, involving presentations, meetings and site visits to the Mogden wastewater treatment works and West Middlesex University Hospital. The council expects to commence the formal procurement in spring 2027, with the contract period currently estimated to begin in April 2028. The Council is supported by Womble Bond Dickenson (UK) LLP, AECOM and Amberside Advisors.