Eastmoor data centre waste heat to warm 2,000 homes in district heating pilot

The rows of fans on the roof of the Eastmoor data centre spend every hour of every day throwing warm air into the sky. From next winter, a good share of that heat will instead be sent through insulated pipes to around 2,000 homes, a primary school and a leisure centre on the edge of the industrial estate.

The data centre's servers draw about 18 megawatts, almost all of which ends up as heat. Water from its cooling circuit leaves the building at around 30 degrees, too cool to warm a house directly. Two large heat pumps being installed in a new energy building next to the site will raise it to 70 degrees before it is pumped into a 4.5-kilometre network of underground pipes.

Households that join will have their gas boilers replaced with a heat exchange unit at no upfront cost. The council-owned heat company running the scheme says bills will be set at least 10 per cent below the equivalent cost of gas heating for the first five years.

How the heat gets home

• Recovered heat covers about 70 per cent of demand on the network

• A thermal store holds 1.2 million litres of hot water for cold snaps

• Gas boilers remain on standby for maintenance and peak days

Councillor Bridget Ollerton, the cabinet member for environment, said the pilot would cut carbon emissions by roughly 3,800 tonnes a year. Engineers have designed the main pipes with spare capacity so that further streets in Eastmoor and Millbrook could be connected later.

Every building in this city that runs computers is also a boiler we have never used.

Residents have questions. At a public meeting in Eastmoor, several asked what would happen if the data centre closed or moved. The heat company says the network is designed to accept other sources, including a large heat pump drawing on water from the River Asher, so homes would not be left without heating. Contracts with households will include a cap on annual price rises linked to inflation.

Hamish Gilchrist, the data centre's site director, said the company had agreed a 15-year heat supply contract and would be paid a modest fee for the energy. He acknowledged that the arrangement also helped the operator, since cooling water returned from the heat pumps is colder and reduces the load on its own chillers. Work on the pipe network begins in the new year, with digging concentrated on two main roads to limit disruption.