TL;DR · 30-second read
The Short Version
Amazon has signed a 20-year deal to buy about a third of the electricity from Calvert Cliffs, Maryland’s only nuclear power plant, which today produces enough for more than 1.3 million homes. The plant’s owner, Constellation Energy, says the deal unlocks more than $3 billion of investment.
The twist: most of that power already exists. Just over a quarter of Amazon’s share will come from new equipment, due between 2030 and 2032. The plant’s two reactors have federal operating licenses that expire in 2034 and 2036, long before the contract ends. The power also stays on the shared grid rather than being walled off for Amazon.
Constellation Energy and Amazon signed a 20-year agreement on Sept. 30, 2026 under which Amazon will buy 690 megawatts (MW) of output from the Calvert Cliffs Clean Energy Center in Maryland, Mugglehead Investment Magazine reported. The 690 MW includes a planned 190 MW capacity increase at the 1,790 MW station, expected to come online between 2030 and 2032. Constellation says the agreement is expected to enable more than $3 billion in Maryland infrastructure investment.
Amazon said electricity from Calvert Cliffs will continue flowing to the PJM regional grid. The companies also signed a separate retail supply agreement covering Amazon operations across PJM’s 13 states and the District of Columbia. Constellation did not disclose a price per megawatt-hour or a spending schedule for the investment.
Executive Summary
Amazon, one of the hyperscalers (the largest cloud and AI computing operators), has committed to two decades of nuclear power from Maryland’s only nuclear plant. The contract covers 690 MW, roughly a third of the station’s output once a planned 190 MW uprate is complete. Constellation ties the deal to more than $3 billion of state investment, to relicensing the plant for another 20 years, and to potential new clean energy plants at the site.
The deal is less about new megawatts than the headline suggests. About 500 MW of the contract comes from reactors already running, and the new 190 MW will not arrive until 2030 to 2032. The larger consequence is financial: a 20-year revenue stream for a station whose two reactor licenses expire in 2034 and 2036 strengthens the case for keeping all 1,790 MW running into the 2050s. The structure matters too. The plant stays connected to the shared grid instead of being dedicated to an Amazon campus built on site.
What remains open is the economics. There is no disclosed price, start date, investment schedule, or relicensing application date. Constellation has also named no design or budget for the new plants it says the deal will help advance.
Most of the 690 Megawatts Already Exists
A megawatt measures generating capacity. Calvert Cliffs’ current 1,790 MW supplies the equivalent of more than 1.3 million homes and about 80 per cent of Maryland’s clean energy, by Constellation’s count. Amazon’s 690 MW contract includes the planned 190 MW increase, so roughly 500 MW of it is output from reactors that are already operating. The 190 MW is an uprate, meaning engineering changes that let existing reactors produce more power. It is not a newly ordered reactor.
For anyone modeling new electricity supply for data center growth in PJM, the timing is the point. In the near term, the deal assigns existing carbon-free output to a named buyer. The net addition to the grid, about a tenth more capacity at the station, arrives between 2030 and 2032.
Amazon’s earlier PJM nuclear agreement follows a similar pattern. Talen Energy’s June 11, 2025 contract covers 1,920 MW from the existing Susquehanna plant in Pennsylvania, reaching full quantity no later than 2032 and running through 2042. Talen treats any extra output from uprates as a separate possibility. Two contracts with one buyer do not make a market-wide trend. Still, both of Amazon’s disclosed PJM nuclear deals are anchored on reactors that already exist, with new capacity small or optional.
Why the 2034 License Date Is the Bigger Stake
The U.S. Nuclear Regulatory Commission (NRC) lists Unit 1’s operating license as expiring July 31, 2034 and Unit 2’s as expiring Aug. 13, 2036. Both licenses were renewed in 2000. A 20-year contract signed in 2026 runs into the mid-2040s at the earliest. If deliveries begin soon after signing, more than half of the term falls after Unit 1’s current license ends. The contract can be fully performed only if the NRC grants subsequent license renewal. That process extends reactor operation from 60 to 80 years and requires its own safety and environmental reviews.
The arithmetic shows where the stake lies. The uprate adds 190 MW. Operation beyond the mid-2030s depends on relicensing for all 1,790 MW, more than nine times as much capacity. Constellation says the agreement helps provide the revenue certainty needed to relicense the plant for another 20 years. That is the mechanism: long-dated contracted revenue is what justifies the cost of a renewal application and the plant investment that goes with it. “Amazon’s commitment supports the long-term operation of Calvert Cliffs for generations to come,” chief executive Joe Dominguez said.
Several parties depend on that outcome. Amazon needs the plant running to receive its contracted supply. Maryland gets most of its clean electricity from this one station. PJM would lose far more capacity if the plant closed than the uprate adds. A power sale does not renew a license, though, and Constellation has given no date for an application. The deal’s most consequential effect is a stronger financial case for keeping the station open. The regulatory decision is still years away.
A Hyperscaler Pays for Nuclear Without Taking It Off the Grid
Amazon said Calvert Cliffs’ electricity will keep flowing to PJM, the operator of the regional grid serving 13 states and Washington, D.C. That footprint includes Northern Virginia, the world’s largest data center market. The main alternative is co-location, in which a data center is built at the plant and draws power directly, “behind the meter,” before it reaches the grid. Co-location has drawn regulatory scrutiny in PJM over its effect on other customers.
Calvert Cliffs instead uses what the industry calls a grid-side power purchase agreement (PPA), a long-term contract to buy a plant’s output. The plant sends its electricity into the grid, and Amazon’s facilities are served through a separate retail supply agreement. Under a structure like this, the buyer underwrites the plant’s revenue while its output stays available to the regional system. That reduces the friction co-location attracts.
The trade-off is that Amazon’s sites still depend on the grid’s ability to deliver power where its data centers are located. The nuclear contract secures a source of electricity, but it does not settle questions of local grid connections or transmission capacity.
The $3 Billion Figure Still Needs a Schedule
Constellation says the deal will “enable” more than $3 billion of Maryland investment. That figure is not described as Amazon’s direct spending, and no spending timeline was given. It is also unclear how the sum divides among the uprate, relicensing work, and the potential new clean energy plants, for which Constellation named no design, equipment order, budget, or completion date.
Without a price per megawatt-hour, outside observers cannot compare the contract with market power prices or judge how much of the plant’s future revenue it locks in. Constellation’s shares rose after the announcement, which suggests investors value the long-term revenue certainty. Overall, the announcement is concrete on duration, volume, and the uprate window, and thin on economics.
Background
Constellation Energy, spun off from Exelon in 2022, operates the largest fleet of nuclear plants in the United States. Calvert Cliffs, on Maryland’s Chesapeake Bay shore, has two reactors totaling 1,790 MW. The company is also working to restart an 835 MW reactor in Pennsylvania under a separate long-term agreement with Microsoft. That unit received an NRC environmental finding on Sept. 25, 2026.
Since 2024, hyperscalers have turned to existing nuclear plants for around-the-clock, carbon-free power for cloud and AI data centers. Many of these deals sit inside PJM, the grid serving 13 states and Washington, D.C., where data center demand has grown fastest. Amazon’s 1,920 MW contract with Talen Energy’s Susquehanna plant, signed in June 2025, is the closest comparable. Source: Constellation Energy signs 20‑year Amazon deal for 690 MW at Calvert Cliffs (Mugglehead Investment Magazine): report on the Sept. 30, 2026 Constellation–Amazon power purchase agreement covering Calvert Cliffs’ output and a planned 190 MW uprate.Sources