Circular system for heat generation in Bristol

Vattenfall Heat UK is committed to removing all new permanent fossil fuel assets from its operations and phasing out all existing gas-fired assets in Bristol by 2030. As part of this commitment, Vattenfall operates England’s largest harbour-based water source heat pump at the Castle Park Energy Centre.

Since 2022, the centre has generated 3 MW of low-carbon heat, and in its first year it was awarded 'Heat Pump City of the Year' by the European Heat Pump Association. It provides heating and hot water to 2,500 homes on the Old Market heat network in Bristol city centre. The heat pump serves various buildings, including new sustainable offices and residential properties.
 
The energy centre operates in three stages: extraction, energy generation and distribution. Water is taken from the harbour, filtered to remove debris including eggs from invasive mussels, and then used in a heat pump. The heat is transferred into a separate water system – the Bristol heat network – and the harbour water is returned just 3–4°C cooler than when it was extracted.

Finally, the hot water is stored and transported to homes and businesses via underground pipes. Vattenfall installs substations to exchange heat between the network and buildings.