Major U.S. utility Constellation said it has completed its acquisition of Calpine Corp. from Energy Capital Partners (ECP), creating the nation’s largest producer of electricity. The companies on January 7 noted that the transaction, first announced as a $16.4-billion deal a year ago, unites Constellation’s nuclear power fleet with Calpine’s natural gas-fired and geothermal generation. The cash-and-stock deal, when including debt, has a total value of $26.6 billion.
The groups said the merged company will power data centers, advanced manufacturing facilities, and critical infrastructure.
“This isn’t just about two great companies coming together—it’s about strengthening America’s future,” said Joe Dominguez, president and CEO of Constellation, in a statement “Constellation is stepping up to power America’s growth when our nation’s demand for energy is surging, and our global competitors are racing to capture AI leadership. By uniting Constellation and Calpine, we’re providing the reliable, clean energy that keeps our communities strong, our businesses competitive and our nation secure.”
‘Exciting Day’
Andrew Novotny, president and CEO of Calpine, said, “This is an exciting day for both our companies and for the customers and communities we serve. We have the assets that power America today and meet the needs of tomorrow. Our expanded capabilities will allow us to better serve customers and communities, enable investment in critical infrastructure and support national priorities for energy security, economic competitiveness and technological leadership. Our teams share a relentless commitment to safety, sustainability and operational excellence, and I’m excited about what we will accomplish together.”
“As a decades-long investor in power generation, ECP aims to unlock value, drive long-term growth opportunities and strengthen asset reliability—often serving as a bridge between public and private markets,” said Tyler Reeder, president and managing partner of ECP. “We are proud to have achieved those goals in partnership with Calpine’s management team and believe this combination validates that vision, setting the company up for future success while meeting the evolving needs of its customers, communities and the U.S.’s electrical grid.”
The combined company will serve 2.5 million retail and business customers nationwide. The groups said the acquisition also strengthens Constellation’s footprint in high-demand regions, including Texas and California, while maintaining significant operations in Illinois, Maryland, New York and Pennsylvania.
Constellation and Calpine together have 55 GW of generation capacity. The company will maintain headquarters in Baltimore, Maryland, along with a significant presence in Houston, Texas.
Antitrust Settlement
The U.S. Justice Department’s Antitrust Division, together with the attorney general of Texas, on December 5 said it would require divestiture of six power plants in Delaware, Pennsylvania, and Texas to resolve antitrust concerns arising from Constellation’s acquisition of Calpine. The Antitrust Division had filed a civil antitrust lawsuit in the U.S. District Court for the District of Columbia to block the proposed acquisition. At the same time, the Division filed a proposed settlement that it said, upon court approval, would resolve the Division’s competitive concerns.
“The price of electricity is a pocketbook issue to American consumers working hard to afford their monthly utility bills. When it comes to their electricity bills, Americans deserve the benefit of robust competition among electricity generators,” said Assistant Attorney General Abigail Slater of the Justice Department’s Antitrust Division. “This settlement includes a six-plant divestiture to an acquisition that risked harming tens of millions of electricity consumers in the mid-Atlantic and Texas. I am appreciative of the partnership with our co-plaintiff, the State of Texas, to secure relief for consumers.”
The DOJ said the divestitures “resolve the Division’s concerns that the acquisition would harm competition and lead to higher prices on consumers reliant on the ERCOT and PJM electricity grids.” Specifically, the settlement requires the companies to divest their ownership interests in four electricity plants serving PJM and two electricity plants serving ERCOT. The divested plants are:
- Bethlehem Energy Center, a natural gas combined cycle plant, located in Bethlehem, Pennsylvania.
- York Energy Center (York 1 and York 2), a dual-fuel combined cycle plant, located southeast of the city of York, Pennsylvania.
- Hay Road Energy Center, a dual-fuel combined-cycle plant, located in Wilmington, Delaware.
- Edge Moor Energy Center, a simple-cycle natural gas plant, located in Wilmington, Delaware.
- Jack A. Fusco Energy Center, a natural gas combined-cycle plant, located southwest of Houston, Texas.
- Gregory Power Plant, a natural gas combined-cycle plant, located northeast of Corpus Christi, Texas.
Officials said it is first settlement consent decree that the Division has filed in an electricity merger in 14 years.
—Darrell Proctor is a senior editor for POWER. This story was originally published on January 9, 2026, and was updated January 19, 2026, with new information from the U.S. Dept. of Justice.
