Electric power production in Oklahoma in 1999 (utility and nonutility) was 55 billion kWh, based on an installed capacity of 13.5 million kW. Coal-fired steam units accounted for 61%, natural gas-fired units 33%, and hydroelectricity 6%. There were no nuclear power plants as of 1 January 1999. In 2000 Oklahoma's total per capita energy consumption was 406 million Btu (102.3 million kcal), ranking it 12th among the 50 states.
Oklahoma is rich in fossil fuel resources, producing oil, natural gas, and coal. Crude oil production declined from 223.6 million barrels in 1968, to 150.5 million barrels in 1978, to 70.6 million barrels in 1999. Production was 183,000 barrels per day in 2002. Proved reserves of crude oil were estimated at 556 million barrels at the close of 2001. In 2002, Oklahoma's natural gas output was 1.62 trillion cu ft (0.05 trillion cu m), leaving reserves of 13.56 trillion cu ft (0.038 trillion cu m).
Production of bituminous coal fell from a record high of 6.1 million tons in 1978 to 1.6 million tons in 2000. Of eight coal mines in the state, all but one were surface mines. Recoverable reserves totaled 19 million tons in 2001.