In 1999, Arizona produced 84 billion kWh of electric power (utility and nonutility); total installed capacity in the same year was 15.3 million kW. The state had 33 power plants, of which 14 were hydroelectric, accounting for 17% of power output. Electric energy retail sales in the state were 57.7 billion kWh; the surplus production was exported to other states, primarily California. The Palo Verde nuclear plant in Maricopa County, which generated electricity for 4 million customers, had the largest combined capacity of any nuclear power facility in the US.
Arizona's fossil-fuel potential remains largely undeveloped, though oil and natural-gas exploration began in the 1980s. In 2002, the state marketed 301 billion cu ft (8.5 billion cu m) of natural gas. Coal production in 2000 was 13,111,000 metric tons, all of it from two surface mines. In 2000 Arizona's total per capital energy consumption was 237 million Btu (59.7 million kcal), ranking it 50th among the states.
Energy resource development in the state is encouraged by the Department of Mines and Mineral Resources, Oil and Gas Conservation Commission, and Department of Water Resources.