Calpine is the largest generator of electricity from

natural gas Natural gas (also fossil gas, methane gas, and gas) is a naturally occurring compound of gaseous hydrocarbons, primarily methane (95%), small amounts of higher alkanes, and traces of carbon dioxide and nitrogen, hydrogen sulfide and helium ...

and geothermal energy in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

, with operations in competitive power markets. A ''Fortune'' 500 company based in

Houston, Texas Houston ( ) is the List of cities in Texas by population, most populous city in the U.S. state of Texas and in the Southern United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the county seat, seat of ...

Operations

Through wholesale power operations and its retail businesses, Calpine serves customers in 24 states,

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, and

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

. Its fleet of 80 power plants in operation or under construction has nearly 26,035 megawatts of generation capacity. In 2019, it reported generating 100.8 million megawatt hours of electricity. Calpine is the largest generator of electricity from natural gas and geothermal resources in the United States. In addition to its retail business, Calpine is a merchant power plant operator that sells power to utilities at market rates.

Subsidiaries

Champion Energy

Champion Energy is a subsidiary of Calpine. It is a retail electricity provider based in

Houston Houston ( ) is the List of cities in Texas by population, most populous city in the U.S. state of Texas and in the Southern United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the county seat, seat of ...

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

. Champion Energy currently serves residential, governmental, commercial and industrial customers in deregulated electric energy markets in Texas,

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a U.S. state, state spanning the Mid-Atlantic (United States), Mid-Atlantic, Northeastern United States, Northeastern, Appalachian, and Great Lakes region, Great Lakes regions o ...

New Jersey New Jersey is a U.S. state, state located in both the Mid-Atlantic States, Mid-Atlantic and Northeastern United States, Northeastern regions of the United States. Located at the geographic hub of the urban area, heavily urbanized Northeas ...

and

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

; governmental, commercial and industrial customers in

Delaware Delaware ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic and South Atlantic states, South Atlantic regions of the United States. It borders Maryland to its south and west, Pennsylvania to its north, New Jersey ...

Maryland Maryland ( ) is a U.S. state, state in the Mid-Atlantic (United States), Mid-Atlantic region of the United States. It borders the states of Virginia to its south, West Virginia to its west, Pennsylvania to its north, and Delaware to its east ...

and

Washington, D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

; and

customers in Illinois.

Fleet

York Energy Center

York Energy Center is a 565-megawatt natural gas-fired power plant located in Peach Bottom Township, York County,

Metcalf Energy Center

The Metcalf Energy Center is a 605-megawatt

combined cycle A combined cycle power plant is an assembly of heat engines that work in tandem from the same source of heat, converting it into mechanical energy. On land, when used to make electricity the most common type is called a combined cycle gas turb ...

power plant located in

Silicon Valley Silicon Valley is a region in Northern California that is a global center for high technology and innovation. Located in the southern part of the San Francisco Bay Area, it corresponds roughly to the geographical area of the Santa Clara Valley ...

, in unincorporated Coyote Valley, south of

San Jose, California San Jose, officially the City of San José ( ; ), is a cultural, commercial, and political center within Silicon Valley and the San Francisco Bay Area. With a city population of 997,368 and a metropolitan area population of 1.95 million, it is ...

and north of Morgan Hill, California. The plant is powered by natural gas. Some of the power generated by the plant is sent to far away places via

Path 15 Path 15 is an portion of the north–south electric power transmission, power transmission corridor in California, U.S. It forms a part of the Pacific AC Intertie and the California-Oregon Transmission Project. Path 15 is part of The Western E ...

, a major electrical power transmission corridor that is connected to the power plant.

The Geysers

The Geysers is the world's largest geothermal field, containing a complex of 15

geothermal power Geothermal power is electricity generation, electrical power generated from geothermal energy. Technologies in use include dry steam power stations, flash steam power stations and binary cycle power stations. Geothermal electricity generation i ...

plants, drawing steam from more than 350 wells, located in the

Mayacamas Mountains The Mayacamas Mountains are located in northwestern California in the United States. The mountain range is part of the Northern Inner Coast Ranges, of the California Coast Ranges System. Geography The Mayacamas Mountains are located south of th ...

approximately north of

San Francisco San Francisco, officially the City and County of San Francisco, is a commercial, Financial District, San Francisco, financial, and Culture of San Francisco, cultural center of Northern California. With a population of 827,526 residents as of ...

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

. Geysers produced about 20% of California's renewable energy in 2019. Calpine owns 13 of the 15 geothermal plants at The Geysers. This group of 15 power plants is the largest producer of renewable geothermal power in North America, producing 725 megawatts of electricity, enough to power 725,000 homes or a city the size of

. Despite the name of the steam field no natural geysers exist in or near The Geysers - Clear Lake area.

Los Medanos Energy Center

The Los Medanos Energy Center is a 561-megawatt natural gas fired co-generation power plant located in

Pittsburg, California Pittsburg (formerly Black Diamond, New York Landing and New York of the Pacific) is a city in Contra Costa County, California, United States. It is an industrial suburb located on the southern shore of the Suisun Bay in the East Bay region of t ...

Edgemoor Power Generating Station

Edgemoor Power Generating Station in Wilmington, Delaware was acquired via the purchase of Connectiv from PEPCO in July 2010.

Russell City Energy Center

The Russell City Energy Center is a 619-

megawatt The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...

natural gas-fired power station, which began operating in August 2013. It is located in

Hayward, California Hayward is a city located in Alameda County, California, United States, in the East Bay subregion of the San Francisco Bay Area. With a population of 162,954 as of 2020, Hayward is the sixth largest city in the Bay Area, and the third largest in ...

. The Russell City Energy Center is the nation’s first power plant to receive a federal air permit that includes a voluntary limit on greenhouse gas emissions.

History

1984–1999

In 1984, Calpine was founded in

. Peter Cartwright and four of his co-workers, the Guy F. Atkinson Construction Company of South San Francisco, and the Electrowatt Corporation struck an investment arrangement. With initial capital of

US$ The United States dollar (Currency symbol, symbol: Dollar sign, $; ISO 4217, currency code: USD) is the official currency of the United States and International use of the U.S. dollar, several other countries. The Coinage Act of 1792 introdu ...

1 million, it was essentially a Silicon Valley startup company. In 1988, the first QF cogeneration plant was commissioned and power production began. The name "Calpine" is derived from the company's original California location and alpine, a reference to the

Zürich Zurich (; ) is the list of cities in Switzerland, largest city in Switzerland and the capital of the canton of Zurich. It is in north-central Switzerland, at the northwestern tip of Lake Zurich. , the municipality had 448,664 inhabitants. The ...

home base of Electrowatt. Electrowatt provided essential assistance when Calpine was a startup. In 1988, the first QF cogeneration plant was commissioned and power production began. In 1992, the company's assets reached US$21 billion. In 1994, the company reached capacity output of 141 MegaWatts. In 1996, the company's

initial public offering An initial public offering (IPO) or stock launch is a public offering in which shares of a company are sold to institutional investors and usually also to retail (individual) investors. An IPO is typically underwritten by one or more investm ...

was the largest for an independent energy company. Sonoma Plant at The Geysers 4778

In 1999, Calpine bought PG&E's holdings at The Geysers, acquiring most of the geothermal complex. The Houston-based company operates 15 plants and produces about 725 megawatts.

2000–2020

In 2001, the California electric energy crisis occurred. In 2004, the investment bank

Lehman Brothers Lehman Brothers Inc. ( ) was an American global financial services firm founded in 1850. Before filing for bankruptcy in 2008, Lehman was the fourth-largest investment bank in the United States (behind Goldman Sachs, Morgan Stanley, and Merril ...

begins

shorting In finance, being short in an asset means investing in such a way that the investor will profit if the market value of the asset falls. This is the opposite of the more common long position, where the investor will profit if the market value ...

Calpine, with researcher Christine Daley lacking confidence in Calpine. This information spreads to clients of Lehman. By the time Calpine goes bankrupt in 2005, Lehman will profit roughly $100,000,000 from the short. In November 2005, CEO Peter Cartwright and CFO Bob Kelly resigned. In 2004, Calpine purchased the Brazos Valley Power Plant in Texas for $175 million. At the time of sale, the natural gas combined cycle plant had a capacity of 570 megawatts. In 2005, the founder and CEO of Calpine, Peter Cartwright, resigned amid severe financial problems for the company. Kenneth T. Derr was named acting CEO. Derr was a retired Chevron executive. On January 31, 2008, Calpine emerged from bankruptcy protection. The company's previous stock was exchanged for warrants and ''new'' Calpine stock began trading on the NYSE under the ticker symbol "CPN." Later that year, a new management team, headed by president and CEO Jack Fusco, joined the company. In 2010, Calpine bought the Conectiv Energy power plant fleet from Pepco for $1.65 billion. The deal included 18 operating plants and one plant that was under construction. The Conectiv acquisition provided access to markets in the Northeast. In 2016, Calpine acquired Noble American Energy Solutions from Noble Group. Calpine paid roughly $800 million with an additional amount of roughly $100 million in net working capital paid at closing. The acquisition was funded with cash-on-hand and a one-year loan of about $550 million. The name of this business unit was changed to Calpine Energy Solutions. In 2018, Calpine was acquired by an affiliate of Energy Capital Partners and a consortium of other investors including Access Industries and the Canada Pension Investment Board. A new board was appointed shortly after the acquisition. As Calpine became a private company its stock stopped trading prior to the opening of the New York Stock Exchange on March 9, 2018. In 2019, Calpine sold its RockGen plant in Wisconsin to Starwood Energy.

2021–present

In February 2023, Calpine released plans to begin development for a 425 MW natural gas-fired plant next to the Freestone Energy Center in Freestone County, Texas. In July 2023, Calpine announced a $25 million carbon capture technology project. The technology could capture 95% of a plant’s carbon emissions, which would reduce greenhouse emissions. The technology was created by ION Clean Energy of Colorado. In January 2025, Constellation Energy agreed to acquire Calpine for $16.4 billion ($26.6bn including debt) in a cash-and-stock deal. In April 2025, ExxonMobil announced that it had reached an agreement with Calpine to carry away and store up to 2 million metric tons of carbon dioxide per year from Calpine's Baytown Energy Center near Houston. This agreement is part of a larger carbon capture and storage project at this site.{{cite news , author1=Staff , title=ExxonMobil, Calpine sign CCS agreement for power generation project , url=https://www.worldoil.com/news/2025/4/23/exxonmobil-calpine-sign-ccs-agreement-for-power-generation-project/ , access-date=28 April 2025 , work=World Oil , date=23 April 2025