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.

Constellation is buying natural gas and geothermal power provider Calpine for $16.4 billion, joining together two of the country's biggest power companies. The acquisition would create the nation’s leading retail electric supplier,

Constellation Energy Corp. agreed to acquire closely held Calpine Corp. for $16.4 billion to add scores of power generation assets across the US as the nation’s electricity demand is forecast to surge.