Fuel Cells
Although their use isn't as widespread as engines or gas turbines, fuel cells offer the potential for clean, quiet, and very efficient power generation, benefits that have driven their development in the past two decades. Fuel cells offer the ability to operate at electrical efficiencies of 40-60% and up to 85% in CHP applications.
However, exhaust temperature varies significantly by the conversion process in the fuel cell. As you can see from the chart below, exhaust temperatures can range from 150C to 1850C and efficiencies range from 25% to 55%. (Understanding CHP)
Like any other generator, it’s important to check the spec sheet of the equipment you have to determine the quantity of heat available.