Constellation Energy — the electricity provider whose stock has doubled over the last year on hopes it’ll help meet the voracious energy demand from artificial intelligence — reached a $16 billion deal to buy Calpine.

Separately, Calpine and Constellation are already among the largest power generation companies in the country.

Constellation is buying power natural gas and geothermal power provider Calpine in a cash-and-stock deal valued at approximately $16.4 billion, joining together two of the country’s biggest power comp

U.S. nuclear power provider Constellation Energy on Friday agreed to buy privately-held natural gas and geothermal company Calpine Corp for $16.4 billion, marking one of the biggest acquisitions in the history of the U.

Constellation Energy agreed to buy Calpine for $16.4 billion, combining two of the country’s largest electricity generators at a time when their product is in high demand from tech companies. Including the assumption of debt,