Tucson Electric Power , an indirect wholly owned subsidiary of Fortis Inc. , joined military and federal officials to dedicate a large solar array at Fort Huachuca that will help the U.S. Army achieve its renewable energy and energy security goals. The 17.2 megawatt array, completed in December, produces enough power to satisfy one-quarter of the base's energy needs, equivalent to the annual electric usage of about 3,000 homes.