What's happening
Constellation Energy confirmed June 15, 2026, that the Crane Clean Energy Center — formerly Three Mile Island Unit 1, shut down in 2019 — is on track for a 2027 restart, with uranium loading planned for spring 2027 and grid connection to follow later that year. The accelerated timeline, roughly a year ahead of prior 2028 projections, was enabled in part by a FERC waiver granted on or around June 2, 2026, permitting the transfer of grid interconnection rights from the Eddystone plant to the Crane facility, clearing a key regulatory hurdle.
The restart is underpinned by a 20-year power purchase agreement between Constellation and Microsoft, under which Constellation will supply all 835 MW of the unit's energy output, capacity, and clean energy attributes exclusively to Microsoft for use at AI data centers. Restart work began in 2024. On a May 11 conference call, Constellation CEO Joe Dominguez addressed grid interconnection timelines, noting that PJM had initially flagged a possible 2031 connection date. Dominguez indicated the timeline is being compressed, stating: "Normally, they start off with a pretty long timeline and shorten that up."
Why it matters for markets
The Crane Clean Energy Center restart represents one of the most closely watched nuclear recommissioning projects in the United States, carrying an estimated $16 billion contribution to Pennsylvania's GDP. For Constellation Energy — which reported $29.87 billion in revenue and carries a market capitalization of approximately $90.62 billion — the 20-year PPA with Microsoft provides long-duration, contracted revenue visibility from a single 835 MW asset, underpinning the financial case for the capital-intensive restart program.
For Microsoft, with a market capitalization of approximately $2.90 trillion and a growing Azure cloud and AI infrastructure footprint, the agreement represents a direct procurement mechanism for large-scale, carbon-free baseload power — a resource increasingly difficult to source at the scale required by hyperscale data center operations. The structure of the deal, covering energy, capacity, and clean energy attributes, addresses both operational power needs and corporate sustainability commitments simultaneously.
The FERC waiver on grid rights transfer illustrates how regulatory decisions at the federal level are directly shaping the pace at which recommissioned nuclear capacity can reach commercial operation. The compression of PJM's initially projected 2031 interconnection timeline to a 2027 target demonstrates that interconnection queue management has become a material variable in nuclear restart economics and project scheduling.
Sectors and assets to watch
Constellation Energy (CEG) is the primary subject of this development, as the operator of the Crane Clean Energy Center and counterparty to the Microsoft PPA. The company's nuclear fleet — the largest in the United States — positions it as the central vehicle through which recommissioned baseload nuclear capacity enters the market. Progress at Crane Clean Energy Center will be monitored as a template for other potential nuclear restart projects across the sector.
Microsoft (MSFT) is the sole offtaker under the 20-year agreement and represents the technology sector's direct engagement with utility-scale nuclear procurement. More broadly, the PJM grid operator and federal regulators at FERC remain critical institutional actors, as interconnection queue decisions and waiver approvals have demonstrated the ability to advance or delay commercial timelines by multiple years. Investors and analysts tracking the intersection of AI infrastructure buildout and clean energy supply chains will find the Crane project a key data point for assessing how nuclear capacity can be contracted and deployed at scale.
What to watch next
Key milestones to monitor include the completion of uranium loading targeted for spring 2027, the subsequent grid connection process within PJM later in 2027, and any further regulatory filings or FERC actions related to the interconnection transfer. Statements from PJM regarding updated interconnection timelines — given CEO Joe Dominguez's May 11 remarks about the initial 2031 projection being shortened — will be material indicators of whether the 2027 commercial operation date holds. Any amendments to the 20-year Microsoft PPA or updates to the projected $16 billion Pennsylvania GDP impact figure would also represent significant developments for the project's financial and policy profile.