Executive Summary
The Federal Energy Regulatory Commission (FERC) is expected to issue a decision by summer 2026 that could determine the timeline for restarting the Three Mile Island nuclear plant. The decision is critical for Constellation Energy’s plan to bring 835 MW of carbon-free, baseload power back online to serve data center demand in the PJM Interconnection market. Microsoft has already committed to a 20-year power purchase agreement for the plant’s output, making this a bellwether project for nuclear restarts across the U.S.
The Players
Constellation Energy, the largest owner of nuclear generation in the U.S., is leading the effort to restart Three Mile Island Unit 1, which was retired in 2019 for economic reasons. Microsoft has signed signed a long-term PPA to secure firm capacity for its growing data center footprint in PJM. PJM Interconnection, the regional grid operator, has indicated that AI and cloud computing growth is driving unprecedented demand for reliable power, and FERC’s decision will clarify how nuclear restarts fit into capacity market structures.
The Numbers
Three Mile Island Unit 1 has a nameplate capacity of 835 MW and can deliver baseload power at a capacity factor exceeding 90%. Assuming a 20-year PPA at an estimated $80–$100/MWh (typical for nuclear PPAs with hyperscalers), the total contract value could exceed $12 billion. Restart costs are estimated at $1.5–$2 billion, including refurbishment, regulatory compliance, and grid interconnection upgrades.
So What?
This is the most important nuclear decision in a decade. If FERC approves the restart and Constellation successfully brings TMI back online, it sets a precedent for other retired nuclear plants to re-enter service. There are roughly a dozen retired U.S. nuclear units that could theoretically be restarted if economics and regulatory pathways align. For hyperscalers chasing 24/7 carbon-free power, nuclear is the only technology that delivers at scale without intermittency.
For power developers and investors, the takeaway is clear: nuclear is back on the table. If you’re developing in PJM or other markets with retired nuclear assets, start evaluating restart economics. The regulatory risk is high, but the upside is enormous—firm capacity with no fuel price risk and a 60+ year operating life.
For utilities and grid operators, this decision will clarify how nuclear restarts interact with capacity markets and transmission planning. If FERC creates a favorable framework, expect a wave of restart proposals. If not, the focus will shift back to new gas generation and storage as the primary solutions for data center load growth.
Source: MSN, May 13, 2026
