Xcel Energy Inc., through its subsidiaries, engages in the generation, purchase, transmission, distribution, and sale of electricity to residential, commercial, and industrial customers, as well as to public authorities in the United States. The company generates electricity using coal, nuclear, natural gas, hydro, wood, diesel, and wind energy. It also engages in the purchase, transportation, distribution, and sale of natural gas to residential, commercial, and industrial customers. The company serves customers in portions of Colorado, Michigan, Minnesota, New Mexico, North Dakota, South Dakota, Texas, and Wisconsin. As of September 19, 2011, it provided a portfolio of energy-related products and services to 3.4 million electricity customers and 1.9 million natural gas customers. Xcel Energy Inc., through its joint venture interests in WYCO Development LLC, develops and leases natural gas pipeline, storage, and compression facilities. The company was founded in 1909 and is based in Minneapolis, Minnesota.