The war in Ukraine has forced a rethink of where we get our energy from as Europe tries to wean itself off Russian gas. But could super-sized heat pumps help to heat thousands of homes and businesses? Two huge schemes are about to be switched on in Gateshead and London - and the hope is they could provide a greener and cheaper source of warmth.
The small, individual heat pumps that people install in their homes work using the same principle. They take some warmth - whether it's from the air or the ground - and then increase the temperature, providing heat for that one household. Jacqueline Bell had one installed in her Gateshead home about five years ago - it's linked in to another local low-carbon network.
The hunt is on for alternatives sources of energy. Michael Lewis, CEO of EON UK, thinks green district heating schemes could help."It means we get off natural gas. So not only is that a benefit for the climate, it also means our energy prices are no longer tied to the volatile international gas market."The power plant in this historic building is going green. BBC Science Editor Rebecca Morelle explains how it works.