Westminster reviews Thames-source heat pump option for Pimlico heat network
UK – Westminster City Council is reviewing a Thames-source heat pump as one of the main options for replacing the ageing Pimlico district heat network, which serves more than 3,000 homes and other buildings in central London.
A previous council assessment ranked full pipework replacement first and a centralised River Thames-source heat pump with gas-boiler support second. However, Westminster reopened the programme in June 2026 and has not selected a preferred solution.
10MW river heat-extraction concept
AECOM has examined an open-loop system at the Churchill Gardens energy centre that would abstract water from the Thames, transfer heat to the heat-pump system and return cooler water to the river.
The early-stage design considered an indicative 10MW river heat-extraction system, described as an upper-limit assumption based on what could be accommodated at the site.
The concept estimated a river-water flow requirement of around 567 litres per second, using four intake filters and pumps rated at approximately 144 litres per second each.
Further work would be required on ecology, filtration, discharge and recirculation modelling, together with approvals involving the Environment Agency, Marine Management Organisation and Port of London Authority.
Five options taken forward
Westminster’s October 2025 Cabinet decision approved five options for further development through the Outline Business Case.
Alongside the Thames-source heat pump with gas-boiler support, these included full pipework replacement while retaining gas boilers, a heat-pump system using electric boilers, mobile heat batteries supplied with waste heat from Cory, and a direct-electric option.
Ageing network under pressure
PDHU operates from the Churchill Gardens energy centre, where heat is currently generated by three gas boilers.
The system is around 50 to 70 years old, with substantial parts beyond their design life. Westminster has reported leaks, deteriorating insulation and rising repair costs.
In March 2025, the council approved £1.2 million for further technical, commercial and financial work and resident engagement.
Review reopened in 2026
Following local elections, Westminster announced in June 2026 that it would review the work undertaken to date and consider all realistic options, including more local block- and estate-based solutions.
The Thames-source heat-pump proposal therefore remains under consideration, with no supplier, final capacity, contractor or construction programme confirmed.
