be 200 degrees f or higher in the embodiment the condenser 304 can be located at the cold water basin of the cooling tower fig8 is a diagram of another alternative embodiment in this embodiment the heat engine evaporator 401 and the condenser 404 are integrated with the cooling tower which arrangement may be easier to package in some applications in the embodiment the heat source for the evaporator is at a lower temperature than the embodiment of fig7 another heat engine that can be utilized in the present invention is a metal hydride heat engine compressors and pumps powered by hydrogen gas pressure differentials between metal hydrides at different temperatures are disclosed in golben et al u s pat no 4 402 187 and golben u s pat no 4 884 953 both of which are incorporated by reference as shown in fig9 of the present specification a metal hydride expansion engine system 510 receives hot or warm fluid 512 water or steam for example from a power plant 514 and receives relatively cold or cool fluid 516 water for example from the cooling tower 518 the temperature difference between the fluids 512 516 drives the engine system 510 and generates electricity to power at least some of the cooling tower equipment for example a fan or pump the hot fluid stream 520 exits the engine 510 and is supplied to the cooling tower 518 the cold fluid stream 522 exits the engine 510 and flows.