A startup called Deep Green has found a unique use for the heat generated by its washing-machine-sized data centres: heating a public swimming pool in Devon. The computers inside the data centre are surrounded by oil that captures the heat, which is then used to warm the pool water via a heat exchanger. This method has been successful in heating the pool to around 30C for 60% of the time, saving the Exmouth Leisure Centre thousands of pounds. The data centre is provided to the council-run centre free of charge, and Deep Green has even agreed to refund the leisure centre's electricity costs for running the "digital boiler." Seven other England-based pools have signed up for the scheme. Despite concerns about the energy usage of data centres, Deep Green's innovative approach proves that these centres can be used for good, as they generate a lot of heat, which can be harnessed for other purposes.