Calpine

Calpine Corporation was a big company based in Houston, Texas. It made a lot of electricity for the United States. The company used natural gas and geothermal energy to create power.

The company was on the Fortune 500 list, which includes the biggest companies in the country. It worked in many places where electricity is bought and sold.

In January 2026, a company called Constellation Energy bought Calpine for $16.4 billion. After that, Calpine became part of Constellation Energy and now works under their name.

Operations

Calpine supplied electricity to customers in 24 states, Canada, and Mexico. It ran 80 power plants and could make almost 26,035 megawatts of electricity.

In 2019, Calpine produced 100.8 million megawatt hours of electricity. Most of this came from natural gas and geothermal energy. It was the largest maker of this type of power in the United States. Calpine sold electricity to customers and also to utility companies.

Subsidiaries

Champion Energy

Champion Energy is part of Calpine and is based in Houston, Texas. It provides electricity to homes, governments, businesses, and industries in places like Texas, Illinois, Ohio, Pennsylvania, New Jersey, and New York. It also serves customers in Delaware, Maryland, and Washington, D.C., and provides natural gas in Illinois.

Fleet

York Energy Center

The York Energy Center is a 565-megawatt power plant that uses natural gas. It is in Peach Bottom Township, York County, Pennsylvania.

Metcalf Energy Center

The Metcalf Energy Center is a 605-megawatt plant that uses natural gas and combined cycle technology. It is in Silicon Valley, near San Jose, California and Morgan Hill, California. Some of its power travels far using Path 15, a major power transmission corridor.

The Geysers

The Geysers is the world's largest area for geothermal power, with 15 plants using steam from deep wells. It is in the Mayacamas Mountains, about 72 miles north of San Francisco, California. In 2019, The Geysers provided about 20% of California's renewable energy. Calpine owned 13 of these 15 plants, which can power 725,000 homes — about the size of a city like San Francisco.

Los Medanos Energy Center

The Los Medanos Energy Center is a 561-megawatt plant that uses natural gas. It is located in Pittsburg, California.

Edgemoor Power Generating Station

The Edgemoor Power Generating Station is in Wilmington, Delaware. It was bought in July 2010.

Russell City Energy Center

The Russell City Energy Center is a 619-megawatt plant that uses natural gas. It started operating in August 2013 and is in Hayward, California. It was the first power plant in the nation to get a special permit to limit greenhouse gas emissions.

History

1984–1999

In 1984, Calpine started in Silicon Valley, California, by Peter Cartwright and his team. It began with just US$1 million as a small new company. By 1988, it made power at its first plant. The name "Calpine" comes from its start in California and “alpine,” after Zürich, where one of its partner companies was based. By 1999, Calpine bought a big geothermal power area called The Geysers, which helped it grow.

2000–2020

In 2001, California had big energy problems. In 2005, Calpine had money troubles and its leader left. The company worked its way out of these troubles by 2008 and started fresh with new leaders. Over the years, Calpine bought many power plants, growing bigger and reaching new areas. In 2018, it became a private company owned by new investors.

2021–present

In 2023, Calpine planned to build a new plant in Freestone County, Texas, and started a project to catch carbon pollution from its plants. In January 2025, Constellation Energy agreed to buy Calpine. By January 2026, the sale was finished, and Calpine became part of Constellation Energy. In 2025, Calpine also made a deal with ExxonMobil to help store pollution from one of its plants.