Development to create UK’s largest water-source heat network

The ‘first of its kind’ technology will initially supply 700 homes, commercial premises, and community buildings, and as Welborne expands developers plans for the network to supply all 15,000 residents in 6,000 new homes with heat, hot water, and cooling.

Clean heat developer and operator, Rendesco, has been commissioned by Buckland Development, the master developer of the site, to deliver the first phase of the network. The network will be owned and operated by Last Mile Heat, the Heat Trust registered low-carbon heat supplier, which is a joint venture between Last Mile and Rendesco.

Rendesco said the new system will increase the garden village’s sustainability credentials by ensuring the project has a reliable and sustainable supply of clean heat and hot water, in addition to cooling technology.

The network draws water from Portsmouth Water’s underground Hoads Hill Reservoir, which the providers said makes it more efficient than air source heat pumps due to the more stable and higher average temperature of the reservoir.

It is set to emit 90 per cent less CO2 emissions than a gas boiler and 50 per cent less than air source heat pumps. It is also cheaper for customers, saving an average three-bedroom house around £160 per year compared with an air source heat pump, according to Rendesco.

A unique feature of the network is its ability to provide cooling in the warmer months by reversing the process and expelling heat back into the reservoir. 

The network also includes an energy exchange function which allows heat to be transferred between homes and other buildings. When one building is cooling, it can supply its excess heat to other buildings in the network which can then be used for central heating or hot water.

The complete network is said to have the potential to save over 272,000 tonnes of carbon in the first 25 years of operation, compared with gas boilers, which adds up to the emissions of over 33,000 average homes.

In a statement, Mark Thistlethwayte, chairman of Buckland Group, said: “Welborne is a new generation sustainable garden village, so our residents and businesses will rightly expect their buildings to be energy efficient and climate-change resilient.

“Partnering with Rendesco and Portsmouth Water we are delivering the largest water-source heating and cooling network in the UK, which will cut carbon emissions and reduce people’s energy bills.”

The announcement comes as housing developers adjust to the Future Homes Standard which will ban gas boilers in new build homes from 2025 and will require new build homes to be equipped with low carbon forms of electrified heat such as heat networks or heat pumps.

Alastair Murray, founder and MD, Rendesco and director, Last Mile Heat, said: “This project is a template for future housing developments of all shapes and sizes and gives developers the confidence to design their projects, no matter how big or small, around our low carbon heat networks.”