CMS Energy Corporation is an American energy company based in Jackson, Michigan, that is focused principally on utility operations in Michigan. Its principal business is Consumers Energy, a public utility that provides electricity and natural gas to more than 6 million of Michigan's 10 million residents. Its non-utility businesses are focused primarily on domestic independent power production. Consumers Energy has operated since 1886. CMS Enterprises' primary businesses are independent power production and natural gas transmission. Wikipedia