Amazon has signed a 20-year agreement with Constellation Energy to buy electricity from the Calvert Cliffs nuclear plant in Maryland, a deal announced on Wednesday that will help power its artificial-intelligence data centers and unlock more than $3 billion in upgrades to the plant.
The agreement covers 690 megawatts from Calvert Cliffs, Maryland's only nuclear plant, out of its roughly 1,790 megawatts of total generating capacity. It is Amazon's first "uprate" project — an upgrade that squeezes more power from an existing plant rather than building a new one.
The deal lands just a month after Amazon walked away from plans to build a data-center campus next to the plant following community opposition.
Residents in the Maryland community raised environmental, resource, and health concerns, part of a growing national backlash against data centers amid fears they could push up local energy prices.
From a Scrapped Campus to a Bigger Plant
Instead of building next door, Amazon will help expand generation at the plant itself. Constellation plans to add about 190 megawatts of new emissions-free capacity — enough to power roughly 147,000 homes — with the extra output expected to come online between 2030 and 2032.
The tech giant is also exploring the possibility of adding entirely new reactors at the site, according to The Wall Street Journal, which first reported the details of the agreement.
For Maryland, the transaction preserves a long-term source of carbon-free electricity: the plant produces about 80% of the state's clean energy and generates enough power for the equivalent of more than 1.3 million homes, while employing about 800 people.
690 Megawatts and a 20-Year Bet
Alongside the power purchase agreement, the companies signed a separate retail electricity supply deal covering Amazon's operations across the 13-state PJM Interconnection market and Washington, D.C., giving the company greater cost predictability across its regional data-center footprint. Deliveries are set to begin in 2027.
The electricity will keep flowing into the regional grid rather than being routed directly to any single Amazon facility, Constellation said — a point aimed at answering local concerns about who actually benefits from the plant's output.
The revenue certainty from Amazon's long-term commitment is expected to support Constellation's push to renew the plant's operating licenses for another 20 years. Unit 1's license expires in 2034 and Unit 2's in 2036, and any extension would require federal regulatory approval.
"This agreement demonstrates how private investment can strengthen critical energy infrastructure," said Joe Dominguez, Constellation's chairman, president, and CEO. "Amazon's commitment supports the long-term operation of Calvert Cliffs for generations to come."
Investors welcomed the news: Constellation shares rose as much as 5% in after-hours trading following the announcement. The investment program will be funded by Constellation itself, not by existing utility customers.
Nuclear Becomes Big Tech's Favorite Power Source
The deal follows earlier nuclear power agreements Constellation struck with Microsoft and Meta, as the biggest technology companies race to lock up reliable, around-the-clock carbon-free electricity for data centers that can consume as much power as a midsize city.
"Bringing net new capacity into that market makes sense — bringing net new carbon-free capacity makes even more sense," said Brandon Oyer, a nuclear engineer who heads Amazon's power and water efforts across the Americas.
Amazon said it is still contracting for wind, solar, and battery-backed power, but is now asking where else it can add new resources on a compressed timeline. With AI infrastructure expanding at breakneck speed, expect more tech giants to go shopping for atoms, not just acres.
