CMS Energy Corporation, through its subsidiaries, operates as an energy company primarily in Michigan. It operates in three segments: Electric Utility, Gas Utility, and Enterprises. The Electric Utility segment engages in the generation, purchase, distribution, and sale of electricity. The Gas Utility segment involves in the purchase, transmission, storage, distribution, and sale of natural gas. The Enterprises segment engages in independent power production and marketing. This segment owns power generation facilities fueled mostly by natural gas and biomass. At December 31, 2009, this segment had ownership interests in independent power plants totaling 1,202 gross Megawatt. The company serves individuals and companies operating in the alternative energy, automotive, chemical, metal, food products, and various other industries. As of December 31, 2009, it served 1.8 million electric customers and 1.7 million gas customers. The company was founded in 1987 and is based in Jackson, Michigan.