Avista Corporation is an American energy company. Avista generates and transmits electricity and distributes natural gas to residential, commercial, and industrial customers. Approximately 1,550 employees provide electricity, natural gas, and other energy services to 359,000 electric and 320,000 natural gas customers in three western states. The service territory covers 30,000 square miles in eastern Washington, northern Idaho, and parts of southern and eastern Oregon, with a population of 1.5 million. Avista Utilities is the regulated business unit of Avista Corp., an investor-owned corporation headquartered in Spokane, Washington. Avista Corp.'s primary, non-utility subsidiary was Ecova, an energy and sustainability management company with over 700 expense management customers, representing more than 600,000 sites. In 2014, Ecova was sold to Cofely, a subsidiary of GDF Suez.