Amazon signs 20-year Calvert Cliffs nuclear power deal

Amazon has signed a 20-year deal to buy 690 megawatts of power from the Calvert Cliffs nuclear plant in Maryland, owner Constellation announced on October 1, 2026. The contract backs a $3 billion upgrade that will add 190 megawatts to the plant between 2030 and 2032. It also gives Constellation a reason to keep the plant's two reactors running for another 20 years. For the cloud industry, it shows how far ahead data center operators now plan their power.

A megawatt (MW) is a million watts. Calvert Cliffs produces 1,790 MW today and will reach 1,980 MW after the upgrade, World Nuclear News reports.

What Amazon and Constellation agreed

The deal is a power purchase agreement, or PPA. That is a long-term contract in which a buyer agrees to pay for a set amount of electricity at an agreed price. Guaranteed income makes it easier for the seller to fund big projects.

Here is what the three reports agree on:

Term	Detail
Buyer	Amazon
Seller	Constellation
Plant	Calvert Cliffs, Maryland
Power contracted	690 MW
Contract length	20 years
Upgrade investment	$3 billion, by Constellation
Extra capacity	190 MW, completed between 2030 and 2032
Current licenses	Unit 1 to 2034, Unit 2 to 2036

The upgrade is called an uprate. It raises the output of reactors that already exist instead of building new ones.

Why the licenses matter

Calvert Cliffs' two reactors are licensed to run until 2034 and 2036. Constellation plans to seek renewed licenses that would extend each by 20 years. The 20-year contract matches that extra license period, ESG Today reports.

A long contract like this lowers the financial risk of relicensing. Constellation knows it has a buyer for much of the plant's output for decades.

Executives on both sides framed it as an investment in the grid. "This agreement demonstrates how private investment can strengthen critical energy infrastructure," said Joe Dominguez, Constellation's chief executive. Kerry Person, an AWS vice president for global operations and data center delivery, said Amazon is "committed to investing in carbon-free energy to strengthen the grid and benefit communities."

David Dardis, a Constellation executive, put it more simply in The Daily Record. "That's a home run for Maryland," he said.

Where the power goes

The electricity does not run to one Amazon building. It flows into PJM, the regional grid that covers 13 states, The Daily Record reports. ESG Today adds Washington, D.C., to that area. The power supports Amazon's data center operations across the region, World Nuclear News says.

Nuclear adds to a long list of clean power deals for Amazon. ESG Today says the company has more than 700 renewable energy projects around the world.

What this means for developers

Do not expect this deal to ease power limits soon. The extra 190 MW arrives between 2030 and 2032. Cloud capacity in power-hungry regions will stay tight for AI workloads until then, so reserve GPU capacity early for big projects.

Use power as a signal when choosing regions. Long contracts like this one show where a cloud provider expects to grow. Ask your provider's account team which regions have room for large new deployments before committing to one.

Ask for region-level carbon data. A 20-year nuclear contract can change the reported carbon footprint of workloads in that grid area. If your company reports emissions, ask your provider for numbers per region, not just a company-wide total.

Watch the relicensing. The deal assumes the reactors keep running past 2034 and 2036. Regulators still have to approve the renewed licenses, and that decision shapes the power supply behind the region for the 2030s.