For more than 120 years, Pinnacle West and our affiliates have provided energy and energy-related products to people and busi ... nesses throughout Arizona. Based in Phoenix, Pinnacle West has consolidated assets of about $11 billion. Our largest affiliate, Arizona Public Service (APS), generates, sells and delivers electricity and energy-related products and services. APS serves more than a million customers in 11 of Arizona’s 15 counties, and is the operator and co-owner of the Palo Verde Nuclear Generating Station® – a primary source of electricity for the Southwest. Our other affiliates include SunCor Development Company, a developer of residential, commercial and industrial real estate; APS Energy Services, a retail energy service provider; and El Dorado Investment Company, a venture capital and investment firm. read more