CMS Energy Corp. engages in the provision of electric and natural gas activities. The company is headquartered in Jackson, Michigan and currently employs 8,356 full-time employees. The firm manages its businesses by the nature of services each provides, and operates principally in three segments: Electric Utility, Gas Utility, and NorthStar Clean Energy. The Electric Utility segment consists of regulated activities associated with the generation, purchase, distribution, and sale of electricity in Michigan. The Gas Utility segment consists of regulated activities associated with the purchase, transmission, storage, distribution, and sale of natural gas in Michigan. NorthStar Clean Energy segment consists of various subsidiaries engaging in domestic independent power production, including the development and operation of renewable generation, and the marketing of independent power production. Its gas transmission, storage, and distribution system consists of over 2,371 miles of transmission lines with 15 gas storage fields with a total storage capacity of 309 billion cubic feet (bcf).