Hydropower presents a means of producing electricity without the use of fossil fuels. In any flow of fluid, energy is present in the form of pressure and flowrate. Hydropower relies upon turbines that have been hydraulically designed to respond to the pressure (referred to as 'head') and flowrate of a stream of water. Microhydropower refers to hydropower installations with capacity of less than 100 kW. Such installations, if applied under the right conditions, offer a clean alternative energy source.