Constellation Energy (CEG -11.18%) is the nation's largest producer of carbon-free energy. It has more than 32.4 GW of power-generating capacity, 90% of which is carbon-free energy. It has the nation's largest nuclear power fleet, which complements its hydro, wind, and solar energy resources. The company provides its carbon-free energy to more than 20 million homes and businesses.
Constellation Energy agreed to buy Calpine to create the country's leading producer of clean and reliable energy. The combined company will operate almost 60 GW of zero- and low-emissions power sources, including nuclear, natural gas, geothermal, hydro, wind, solar, cogeneration, and battery storage.
Constellation Energy is also helping jump-start the country's nuclear power renaissance. It's working to restart Three Mile Island Unit 1, which it shut down for economic reasons several years ago. However, technology giant Microsoft (MSFT -1.92%) signed a 20-year power purchase agreement for all 835 megawatts of the unit's capacity to support its cloud and AI power needs. Constellation also signed a 20-year nuclear power deal with Meta Platforms (META -2.15%) for 1.1 GW of power from its Clinton Clean Energy Center starting in mid-2027.
5. GE Vernova