The amount of gross generation less the electrical energy consumed at the generating station(s) for station service or auxiliaries. Electricity required for pumping at pumped-storage plants is regarded as electricity for station service and is deducted from gross generation. Both conventional and combined hydroelectric plants. Conventional hydroelectric plant is a plant in which all of the power is produced from natural streamflow as regulated by available storage. Combined hydroelectric plant is a hydroelectric plant that uses both pumped water and natural streamflow for the production of power.