Deep Green uses waste heat from its data centres to heat swimming pools, reducing their carbon emissions and keeping them afloat as energy costs soar.

Data centres consume huge amounts of energy – and generate plenty of heat in the process. In Sweden, thousands of households are already heated with server heat. Could this be a potential source of clean energy?

It sounds too good to be true. But more and more venues and companies are finding ways to turn body heat into usable energy.

What if the heat from, say, server farms or subway tunnels can be used to warm homes? Waste heat recovery technologies seek to close the energy loop.