Nearly a month after Microsoft bet $16 billion on reviving the defunct Three Mile Island nuclear plant to power its energy-hungry data centers, Google and now Amazon are inking massive deals to finance the United States ambitious atomic revival plans.

On Wednesday morning, Amazon Web Services announced a megadeal with two utilities to fund the construction of next-generation nuclear plants near its server farms in Virginia and Washington.

Unlike its rivals recent deals, the tech giant isnt just agreeing to buy nuclear-generated electricity. Amazon teamed up with billionaire Ken Griffin to pump $500 million into X-energy, a Maryland-based startup designing small modular reactors that are a fraction of the size of conventional units and use high-temperature gas as a coolant instead of water.

Amazon and X-energy are poised to define the future of advanced nuclear energy in the commercial marketplace, X-energy CEO J. Clay Sell said in a news release .

The investment mirrors Amazons purchase of a double-digit stake in Rivian around the same time the company ordered a fleet of the electric automakers battery-powered delivery trucks. Amazon has similarly big plans to scale its latest green gamble, promising to build 5 gigawatts equal to 5,000 megawatts of new nuclear power plants in the U.S. over the next 15 years using X-energys 80-megawatt reactors.

Its the old Hair Club for Men commercials Im not just the president, Im also a client, said Brett Rampal, a nuclear power expert at the hedge fund Segra Capital Management.

Its all about getting skin in the game. We need these companies to actually be deep in. Some companies are struggling with that, but it seems Amazon is leaning directly into this deal.

The announcement came two days after Alphabet-owned Google unveiled a far more modest deal to buy up to 500 megawatts of power from Kairos Power, another so-called advanced reactor developer that uses fluoride salt instead of water to cool the fission reaction.

This is unbridled good news for the nuclear industry in that we are getting a clear demand signal from some of the most well-resourced private corporations on Earth that there is a need and a market for new nuclear generation, said James Krellenstein, a physicist and industry historian who now serves as the chief executive of the Cambridge, Massachusetts-based nuclear consultancy Alva Energy.