Exergyn has developed an engine that runs on hot water – the Exergyn Drive™ – which could resolve the low-grade waste heat problem for the first time. The Exergyn Drive™ is the first new class of heat engine to be developed since the diesel engine in the 1890s. Waste heat is an enormous problem in power generation, industrial processes and transport. We estimate that the amount of low grade waste heat lost each year is equivalent to twice the annual energy output of Saudi Arabia. Exergyn has developed an innovative solid state engine which will enable utilisation of low grade waste heat enabling companies to increase revenues, reduce energy bills and reduce emissions.