Amazon and Constellation Sign 690 MW Nuclear Deal to Expand Calvert Cliffs
Amazon's 20-year agreement with Constellation covers 690 MW and supports 190 MW of additional nuclear generation at Calvert Cliffs in Maryland.
Published · 3 min read
Constellation and Amazon announced a 20-year power agreement on September 30 that will support approximately 190 MW of new generation at Maryland’s Calvert Cliffs nuclear plant. The Amazon Calvert Cliffs nuclear deal covers 690 MW of power, including the planned uprate, and is expected to support more than $3 billion in infrastructure investment in Maryland.
The additional capacity is scheduled to enter service between 2030 and 2032, not immediately. Constellation says every megawatt generated at Calvert Cliffs will continue flowing into the regional PJM electricity grid. A related retail supply arrangement will serve Amazon’s operations across the PJM market; the agreement does not establish a dedicated transmission connection between the plant and a particular Amazon data center.
Amazon Calvert Cliffs nuclear deal supports a 190 MW uprate
In its September 30 announcement, Constellation said the 20-year contract covers 690 MW, of which roughly 190 MW would come from improvements that increase the output of the existing plant. The other 500 MW is part of the contract’s total power volume, not additional generating capacity.
Calvert Cliffs currently has approximately 1,790 MW of generating capacity. An uprate of 190 MW would raise its output if the planned equipment upgrades are completed and perform as expected. Constellation has not published a unit-by-unit construction timetable or guaranteed that all additional megawatts will be available before the 2030–2032 window.
World Nuclear News independently reported the 20-year contract, the 690 MW volume and the planned 190 MW expansion. The commitment is a newly announced commercial agreement, whereas Constellation had previously identified a Calvert Cliffs uprate as a potential investment requiring customer support.
The power remains on the regional grid
Constellation explicitly said Calvert Cliffs will continue supplying the PJM regional grid as it does today. That distinction matters for the power-sector implications: Amazon is supporting existing and incremental generation through a long-term contract, rather than placing an isolated power plant behind a single computing facility’s meter.
Amazon has pursued other approaches to data-center electricity. Microgrid Media previously covered its North Carolina data-center power permits, which distinguish permanent emergency generators from temporary bridge generation while utility service is developed. Those site-specific systems perform a different role from a grid-connected nuclear power purchase agreement.
The Calvert Cliffs arrangement also differs from integrated behind-the-meter AI power projects in Texas that combine dispatchable generation, batteries and controls close to computing loads. Neither design is a direct substitute for the other: a regional power agreement supports generation investment, while on-site systems address local power availability and resilience requirements.
The agreement supports upgrades and a longer operating horizon
Constellation expects the Amazon commitment to help underpin more than $3 billion of Maryland infrastructure investment, including improvements across the existing station. It also says the contract provides revenue certainty for seeking another 20 years of operation through license renewal.
The plant’s published licensing information identifies current operating-authority dates extending through 2034 for Unit 1 and 2036 for Unit 2. A further extension is an objective supported by the agreement, not an approval already issued by the Nuclear Regulatory Commission.
Constellation and Amazon also plan to explore future clean-energy development at the site, including advanced nuclear possibilities. No additional reactor has been authorized, financed or given a construction date through this agreement, and the proposed future projects should not be counted as part of the 190 MW uprate.
New generation will arrive after today’s PJM capacity challenge
The timing is important. PJM faces growing demand from data centers and other large customers, while its recent capacity auction procured less supply than the system’s stated reliability requirement. Microgrid Media has reported on PJM’s proposed backstop procurement as one response to that imbalance.
Calvert Cliffs’ planned new capacity would add firm generation within PJM, but it is not scheduled to arrive until 2030–2032. It therefore should not be described as an immediate solution to a nearer-term resource-adequacy shortfall. The contract’s nearer-term contribution is to support continued plant operation and the investment decision for additional capacity.
The Amazon Calvert Cliffs nuclear deal illustrates a way a large electricity customer can help underwrite generation that serves the wider grid. Its ultimate effect will depend on completion of the uprate, continued operation of the existing units and the approvals needed for the plant’s longer operating horizon.
