Constellation Energy’s deal to buy Calpine is being driven by fast-rising demand for electricity in part by the technology industry’s investments in artificial intelligence.

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 companies.

Constellation Energy Corp., an electricity provider whose stock has doubled over the last year on hopes it will help meet the voracious energy demand created by artificial-intelligence technologies, on Friday reached a $16.