Sierra Pacific Resources, through its subsidiaries, engages in the generation, transmission, and distribution of electric energy in southern Nevada. It operates in three segments: NPC Electric, SPPC Electric, and SPPC Natural Gas. The NPC Electric segment consists of approximately 27 gas, oil, and coal generating units with a combined capacity of 3,148 megawatts. As of December 31, 2006, it served approximately 807,000 residential, commercial, industrial, and wholesale customers in Las Vegas, north Las Vegas, Henderson, Searchlight, and Laughlin, as well as in adjoining areas, including Nellis Air Force Base and the Department of Energy’s Nevada Test Site in Nye County. The SPPC Electric segment owns approximately 24 gas, oil, and coal generating units with a combined capacity of 1,043 megawatts. The SPPC Natural Gas segment provided natural gas services to approximately 146,000 customers in Reno/Sparks area, Nevada, as well as owned and operated approximately 1,988 miles of distribution pipelines, as of the above date. The company also operates an interstate natural gas pipeline from Malin, Oregon to Reno, Nevada. Sierra Pacific was founded in 1906 and is based in Reno, Nevada.