Constellation Energy

Constellation Energy Corporation
Company type	Public
Industry	Energy
Predecessor	Baltimore Gas and Electric (holding company formation)
Founded	1999; 27 years ago in Baltimore, Maryland, United States
Fate	Merged with Exelon in 2012; re-established as independent company in 2022
Successor	Exelon (2012–2022)
Headquarters	Baltimore, United States
Area served	Continental United States
Products	Electric power, natural gas, energy management solutions
Parent	Independent (post-2022 spin-off from Exelon)

Constellation Energy Corporation is a U.S.-based energy firm with its headquarters located in Baltimore, Maryland. It delivers electric power, natural gas, and energy management solutions to nearly two million customers throughout the continental United States.

Formerly operating as Constellation Energy Group, a Fortune 500 company and one of the nation’s leading electricity producers, it merged with Exelon in 2012. After this merger, the energy supply segment was integrated under the Exelon brand, while Baltimore Gas and Electric continued as part of Exelon Utilities. In 2022, Constellation was re-established as an independent entity following a corporate spin-off from Exelon.

Prior to merging, Constellation Energy Group managed more than 35 power generation facilities across 11 states, with a focus on Maryland, Pennsylvania, New York, West Virginia, and California. The company originated in 1999 as a holding company formed by Baltimore Gas and Electric.

History

On September 15, 2005, Constellation Energy partnered with Areva to create UniStar Nuclear, aiming to introduce the European Pressurized Reactor (EPR) technology to the U.S. market. Later that year, on December 19, FPL Group announced plans to acquire Constellation Energy for $11 billion and retain the Constellation name post-merger; however, this transaction was called off on October 25, 2006.

In mid-2008, Constellation expanded its portfolio by purchasing Nufcor International, a uranium trading company formerly owned by AngloGold Ashanti and FirstRand International. Following the collapse of Lehman Brothers in September 2008, Constellation’s stock value dropped sharply by 56%, resulting in a temporary trading suspension. The company engaged Morgan Stanley and UBS to evaluate strategic options, including potential acquisition offers. On September 17, MidAmerican Energy—a Berkshire Hathaway subsidiary—proposed a $4.7 billion bid for Constellation but withdrew in December 2008 after Electricite de France (EDF) presented a $4.5 billion offer which was accepted.

January 2009 saw Constellation divest most of its London-based international commodities operations to an affiliate of Goldman Sachs. In April 2010, it acquired Maryland’s Criterion Wind Project from Clipper Windpower along with 28 wind turbines; construction was completed by December that year. May 2010 marked the purchase of two Texas natural gas combined-cycle plants from Navasota Holdings for $365 million, adding approximately 1,100 MW of generating capacity.

Exelon announced its intention to acquire Constellation on April 28, 2011; the merger was completed on March 12, 2012. Before this consolidation, Constellation expanded its retail footprint by acquiring Houston-based StarTex Power in June 2011 (discontinued in 2018), MXenergy with roughly half a million customers in May 2011, and ONEOK Energy Marketing Co. in December 2011. Additionally, in 2011 it developed the largest rooftop solar installation at Toys-R-Us’s distribution center in New Jersey.

Growth continued with the acquisition of ETC ProLiance Energy in March 2014 and Integrys Energy Services in November 2014—both adding retail electricity and natural gas customers across several states. In September 2016, Constellation purchased the retail energy division of ConEdison Solutions serving over 560,000 commercial and residential clients.

In August 2018, construction began on a 10 MW solar facility near Ocean City, Maryland designed to supply approximately one-fifth of the city’s yearly energy consumption. By October of that year, a solar installation project was completed for Tucson Unified School District covering 82 sites and fulfilling an estimated 47% of their electricity needs.

Following Exelon’s separation of its utility and power generation segments in 2022, Constellation resumed operations as an autonomous company based in Baltimore; meanwhile Baltimore Gas & Electric remained under Exelon’s control.

In September 2024, Microsoft engaged Constellation to reactivate an undamaged nuclear reactor at Three Mile Island and enhance additional reactors to boost their power output.

By January 2025, Constellation agreed to purchase Calpine—a provider of natural gas and geothermal energy—in a cash-and-stock transaction valued at $16.4 billion ($26.6 billion including debt), subject to regulatory approval.

Electric power

Constellation delivers electric power services to commercial and industrial clients, overseeing energy sales, dispatch, and delivery sourced from Exelon's generation assets to utilities, municipal cooperatives, and energy retailers across the United States. By 2018, the company operated or was constructing approximately 360 megawatts of solar capacity in various states including Maryland, California, Arizona, New Jersey, and Texas. Notably, in 2011, Constellation developed and managed what was then the largest rooftop solar installation for the Toys-R-Us distribution facility located in New Jersey.

Through its offsite renewables offering known as CORe, Constellation provides customers with renewable energy access via retail power agreements that combine geographically specific renewable purchases and certificates alongside physical load-following energy delivery.

Natural gas

Handling nearly 730 billion cubic feet of natural gas each year, Constellation ranks within the top ten natural gas marketers in the U.S. The company oversees activities such as trading, transportation, storage, pricing strategies, hedging, and risk management related to physical natural gas supplies.

Constellation Technology Ventures

The venture capital division of Constellation, named Constellation Technology Ventures (CTV), focuses on investing in startups that develop cutting-edge energy technologies. Its investment portfolio features companies such as Proterra, ChargePoint, and Aquion Energy.

Nuclear

As the foremost operator of nuclear power plants in the United States, Constellation manages a nuclear portfolio exceeding 19,000 megawatts of capacity. The nuclear facilities under its operation include:

Braidwood Nuclear Generating Station (Illinois)
Byron Nuclear Generating Station (Illinois)
Calvert Cliffs Nuclear Power Plant (Maryland)
Clinton Nuclear Generating Station (Illinois)
Dresden Generating Station (Illinois)
Ginna Nuclear Generating Station (New York)
James A. FitzPatrick Nuclear Power Plant (New York)
LaSalle County Nuclear Generating Station (Illinois)
Limerick Nuclear Power Plant (Pennsylvania)
Nine Mile Point Nuclear Generating Station (New York)
Peach Bottom Atomic Power Station (Pennsylvania)
Quad Cities Nuclear Generating Station (Illinois)
Salem Nuclear Power Plant (New Jersey) (minority ownership)
Three Mile Island Nuclear Generating Station (Pennsylvania) (Unit 2 owned by EnergySolutions)
South Texas Nuclear Generating Station (Texas) (minority ownership)

Fossil

Constellation operates a fossil fuel generation portfolio exceeding 12,000 megawatts that includes oil and natural gas facilities throughout the U.S. and Canada. Principal plants consist of:

Chester Generating Station – oil-fired (Pennsylvania)
Colorado Bend II Energy Center – natural gas-fired (Texas)
Eddystone Generating Station – dual-fuel natural gas and oil (Pennsylvania)
Everett LNG Facility – natural gas import terminal (Massachusetts), acquired in 2019
Mystic Generating Station – natural gas-fired (Massachusetts)
Perryman Generating Station – combined oil and natural gas (Maryland)
Wolf Hollow II Generating Station – natural gas-fired (Texas)

Additional assets are located across Pennsylvania, Massachusetts, Maryland, Alabama, Maine, and Alberta in Canada.

Hydro

Constellation’s hydroelectric operations produce approximately 1,600 megawatts through two primary facilities:

Conowingo Dam (Maryland)
Muddy Run Pumped Storage Facility (Pennsylvania)

Solar

Antelope Valley Solar Ranch One located in California

Wind

The company operates 27 wind energy facilities spread over ten states, with a combined capacity approaching 1,400 MW.

Generation services

Constellation is the owner of Constellation Generation Solutions (CGS), a top-tier provider specializing in maintenance and technical services aimed at enhancing the performance of nuclear power plants.

Its division, Constellation PowerLabs, founded in 1911, functions as Exelon's main calibration and testing center, featuring four laboratories strategically positioned from the Midwest through to the Northeast. PowerLabs delivers essential support in engineering, metrology, and nuclear power generation, playing a vital role in sustaining national electricity grids and supply networks.

Historical archives

Constellation preserves the historical records of Baltimore Gas & Electric Company and its antecedents, which include around 250,000 photographic prints and negatives. These collections are stored at the Baltimore Museum of Industry.

Philanthropy

Among Baltimore-based corporations, Constellation ranks second for local charitable contributions, having donated $7.10 million in 2017. The company invests in education initiatives that emphasize science and technology by providing grants to area schools.

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