Microturbines are relatively small combustion turbines that can use gaseous or liquid fuels. They emerged as a CHP option in the 1990s. Individual microturbines range in size from 30 to 330 kilowatts (kW) and can be integrated to provide modular packages with capacities exceeding 1,000 kW. There are over 360 sites in the United States that currently use microturbines for CHP, accounting for over 8% of the total number of CHP sites and 92 MW of aggregate capacity. In CHP applications, thermal energy from microturbine exhaust is recovered to produce either hot water or low pressure steam.