What Constellation does
Constellation Energy generates electricity and sells power, natural gas and related services to utilities, businesses, public bodies and households. It is headquartered in Baltimore and listed on Nasdaq. Reuters describes it as the largest U.S. operator of nuclear power plants and the owner of a major fleet of gas-fired plants. The company says its plants total 55 gigawatts (GW) of generating capacity. A gigawatt is 1,000 megawatts (MW).
It became a separate company in February 2022, when Exelon completed the separation of its power generation and competitive energy business. Exelon kept its regulated utilities. Constellation's nuclear page lists 15 sites in Illinois, Maryland, New York, Pennsylvania, New Jersey and Texas. One of them, Crane in Pennsylvania, is shut down and being prepared for a restart.
On January 7, 2026 it completed the acquisition of Calpine, according to its filing for the second quarter of 2026. Calpine's natural gas, oil, geothermal, battery storage and solar plants total about 23 GW after the sales regulators required. The Justice Department's clearance required selling five plants in Delaware and Pennsylvania and one in Texas, plus a minority stake in another Texas plant. The filing says Constellation has agreed to sell the six plants to LS Power and expects those sales to close by the end of 2026.
Nuclear power deals with technology companies
Since 2024 Constellation has announced long-term agreements with four large technology companies:
- Microsoft. In September 2024 it announced a 20-year power purchase agreement to restart Three Mile Island Unit 1 as the Crane Clean Energy Center. The unit closed for economic reasons in 2019.
- Meta. In June 2025 Meta signed a 20-year agreement for the 1,121 MW output of the Clinton plant in Illinois, beginning in June 2027.
- Amazon. On September 30, 2026 the companies announced a 20-year agreement that includes 690 MW of power, among them a planned 190 MW capacity increase at Calvert Cliffs in Maryland.
- Google. On October 6, 2026 the companies announced a 20-year agreement to fund upgrades adding 890 MW at 11 reactors in Illinois, Pennsylvania and New Jersey. They also announced a 15-year supply agreement for 2,700 MW. Reuters reported Google as saying that power is not tied to a specific generation source. The companies say Constellation will invest more than $4.3 billion and that the first upgrade is expected by 2028.
Raising a reactor's licensed power level requires approval from the Nuclear Regulatory Commission (NRC). The NRC's list of expected applications, last reviewed or updated on September 8, 2026, has 12 entries naming Constellation Energy Generation as applicant. The plant names are marked proprietary.
The Crane restart
Restarting Crane also needs NRC approval. Constellation first expected the plant online in 2028. Nuclear News reported in August 2026 that the NRC and the Federal Energy Regulatory Commission (FERC) each approved a request tied to the restart in the second quarter. It also reported that chief executive Joe Dominguez said this paves the way for a restart in the second half of 2027. The Energy Department guaranteed a loan of up to $1.0 billion for the project in November 2025. The second-quarter filing said nothing had yet been borrowed under it.
What to watch
- Which reactors the Google agreement covers and when each upgrade is finished.
- Crane's restart, which the chief executive said in August 2026 could come in the second half of 2027.
- Completion of the plant sales required in the Calpine acquisition.
Constellation Energy timeline
Google and Constellation announce a 20-year agreement to fund upgrades adding 890 MW at 11 nuclear units, plus a 15-year supply agreement for 2,700 MW.
Source: Constellation Energy
Constellation and Amazon announce a 20-year agreement that includes 690 MW of power, among them a planned 190 MW capacity increase at Calvert Cliffs in Maryland.
Source: Constellation Energy
FERC grants Constellation's request to transfer capacity interconnection rights from the Eddystone plant to Crane, a step aimed at reducing required grid upgrades.
Constellation completes its acquisition of Calpine, which owns natural gas, geothermal and other power plants.
The Energy Department guarantees a loan of up to $1.0 billion to support the restart of the Crane Clean Energy Center.
Constellation announces a 20-year agreement with Meta for the 1,121 MW output of the Clinton nuclear plant in Illinois, beginning in June 2027.
Source: Constellation Energy
Constellation announces a 20-year agreement with Microsoft to restart Three Mile Island Unit 1 as the Crane Clean Energy Center.
Source: Constellation Energy
Exelon announces it has completed the separation of Constellation, which begins regular trading on Nasdaq under the symbol CEG.
Source: Exelon (filed with the U.S. Securities and Exchange Commission)
Sources
- Google and Constellation Announce Landmark Agreement to Bring 890 MW of New Nuclear Capacity to PJM Grid as Part of Long-Term Power Deal, Constellation Energy
- Constellation and Amazon Announce 20-Year Power Purchase Agreement Adding 190 Megawatts of Nuclear Capacity at Calvert Cliffs, Constellation Energy
- Constellation, Meta Sign 20-Year Deal for Clean, Reliable Nuclear Energy in Illinois, Constellation Energy
- Constellation to Launch Crane Clean Energy Center, Restoring Jobs and Carbon-Free Power to The Grid, Constellation Energy
- Nuclear Generation, Constellation Energy
- Constellation Energy Corporation Form 10-Q for the quarterly period ended June 30, 2026, U.S. Securities and Exchange Commission (EDGAR)
- Exelon Completes Separation of Constellation, Moving Forward as Nation's Premier Transmission and Distribution Utility Company, Exelon (filed with the U.S. Securities and Exchange Commission)
- Google enters massive 3.6-GW power deal with Constellation Energy, Reuters (via CNBC)
- Second-quarter updates from Constellation: New PPAs, Crane restart, and more, American Nuclear Society
- Backgrounder on Power Uprates for Nuclear Plants, U.S. Nuclear Regulatory Commission
- Expected Applications for Power Uprates, U.S. Nuclear Regulatory Commission
