It has a lower efficiency than the aero-derivative type, but usually maintains its performance over a longer period of operation. Maintenance can easily be carried out on site. Maintenance costs are low. The industrial gas turbine usually has a lower specific investment cost than its aero-derivative counterpart. Furthermore, it can use lower quality fuel.
Heat is recovered in a boiler by using the hot exhaust gases to produce steam or hot water.
The boiler may be unfired or employ supplementary firing. It is possible to dispense with the heat recovery boiler in applications where the exhaust gas heat can be used either directly for air preheating or drying, or indirectly, by passing the gases through a heat exchanger to produce hot water or steam for process needs. Gas turbine cogeneration plants have distinct advantages. These advantages mean gas-turbine systems are, and will remain, the most popular selection for cogeneration over about 3MWe. The plants represented a variety of industrial sectors and sizes.