Regulation is one of the ancillary services that hydropower plants can supply in addition to power to increase the reliability and flexibility of the power system to adjust to fluctuations in power demand and supply. When a plant is regulating it will follow the load within some prescribed band of power rather than generating a fixed amount of power. Typically, regulation is a valuable service that can be provided efficiently by hydropower compared to alternative power sources. In locations where regulation is marketed it usually commands a solid premium above the price of the power generated. This value is partially reduced by the increased maintenance costs associated with regulation.

See Regulation in Objects and Methods for the methods in this category.