In addition to an existing installed capacity of 1.65 gigawatts (GW) of hydro-electric schemes, Scotland has an estimated potential of 36.5 GW of wind and 7.5 GW of tidal power, 25% of the estimated total capacity for Europe and up to 14 GW of wave power potential, 10% of European capacity. It should be borne in mind that electricity production is only part of the overall energy use budget. In 2002, Scotland consumed a total of 175 Terawatt-hours (TWh) of energy in all forms, some 2% less than in 1990. Of this, only 20% was consumed in the form of electricity by end users, the great majority of energy utilised is from the burning of oil (41%) and gas (36%). Nonetheless, the renewable electricity generating capacity may be 60 GW or more, greater than required to provide the existing energy provided from all Scottish fuel sources of 157 TWh.