AICPA SOC Service Organizations - Certrec
Market Research

Top Ten Largest U.S. Electric Utility Companies

Largest U.S. Electric Utility Companies Ranked by Generation Capacity

In the United States, numerous companies have emerged as leaders in providing electricity services to millions of consumers nationwide. Below are the 10 largest U.S. electric utility companies1.

10. Calpine Corp

Calpine Corp is a large generator of electricity from natural gas and geothermal resources. Their fleet of 76 power plants in operation or under construction represents more than 26,000 megawatts of generation capacity — enough to power approximately 20 million homes. Through wholesale power operations and retail businesses Calpine Energy Solutions and Champion Energy, they serve customers in 22 states, Canada and Mexico.

9. Entergy

Entergy owns and operates one of the cleanest large-scale U.S. power-generating fleets including more than five gigawatts of carbon-free nuclear capacity, a fleet of highly efficient gas resources, and a fast-growing portfolio of renewable resources.

8. MidAmerican Energy

MidAmerican Energy is a certified retail energy provider serving customers in deregulated electric markets since 1999 and natural gas markets since 1986 (previously as MidAmerican Energy Company). MidAmerican Energy meets the energy needs of nearly 1.6 million customers in Iowa, Illinois, Nebraska, and South Dakota.

7. Exelon

Exelon is one the nation’s largest utility companies, serving more than 10 million customers through six fully regulated utilities. Operating across a large urban footprint, Exelon serves major metro areas in Delaware, the District of Columbia, Illinois, Maryland, New Jersey, and Pennsylvania. 

6. Tennessee Valley Authority

Tennessee Valley Authority has provided affordable electricity, environmental stewardship, and economic development opportunities to the Tennessee Valley. TVA was established by Congress in 1933 to address a wide range of environmental, economic, and technological issues, including the need for low-cost electricity, and navigation and flood control along the Tennessee River system.

5. American Electric Power

American Electric Power AEP ranks among the nation’s largest generators of electricity, owning nearly 38,000 megawatts of generating capacity in the U.S. AEP also owns the nation’s largest electricity transmission system, a nearly 39,000-mile (63,000 km) network that includes 765-kilovolt ultra-high voltage transmission lines, more than all other U.S. transmission systems combined.

4. NextEra Energy

NextEra Energy is an American energy company with about 58 GW of generating capacity (24 GW of which were from fossil fuel sources), revenues of over $18 billion in 2020, and about 14,900 employees throughout the US and Canada. It is the world’s largest electric utility holding company by market capitalization, with a valuation of over $120 billion as of Nov 2023.

3. Southern Company

Southern Company is an American gas and electric utility holding company based in the southern U.S. It is headquartered in Atlanta, Georgia, with executive offices also located in Birmingham, Alabama. The company is the second largest utility company in the U.S. in terms of customer base, as of 2021. Through its subsidiaries, it serves 9 million gas and electric utility customers in 6 states.

2. NRG Energy

NRG Energy is an American energy company, headquartered in Houston, Texas. It was formerly the wholesale arm of Northern States Power Company, which became Xcel Energy, but became independent in 2000. NRG Energy is involved in energy generation and retail electricity. NRG serves over 7 million retail customers in 24 US states including Texas, Connecticut, Delaware, Illinois, Maryland, Massachusetts, New Jersey, New York, Pennsylvania, Ohio; the District of Columbia, and eight provinces in Canada.

1. Duke Energy

Duke Energy‘s Electric Utilities and Infrastructure business unit serves approximately 7.5 million customers located in six states in the Southeast and Midwest. The company’s Gas Utilities and Infrastructure business unit distributes natural gas to approximately 1.6 million customers in the Carolinas, Ohio, Kentucky, and Tennessee. During 2006, Duke Energy generated 148,798,332 megawatt-hours of electrical energy.

[1] Source: