Constellation Energy Stock Rises. What’s the Plan for the Former Three Mile Island?

Constellation Energy said in 2024 that it planned to restart the Three Mile Island nuclear power plant after landing a deal with Microsoft. (Bloomberg)

Key Points

• Constellation Energy trades higher after the Department of Energy confirms a $1 billion federal loan.
• The loan will facilitate the reopening of the Three Mile Island Unit 1 nuclear power plant, renamed Crane Clean Energy Center.
• The plant, scheduled to restart in 2027, secured a power purchase agreement with Microsoft in late 2024.

Constellation Energy was back in the spotlight Wednesday after the Trump administration said it would provide the company with a $1 billion federal loan to restart shuttered nuclear power plant Three Mile Island in Pennsylvania.

The Department of Energy confirmed late Tuesday that it was backing Constellation Energy’s plan to reopen Three Mile Island Unit 1, a reactor that is set to start producing power again in 2027, eight years after its shutdown.

The first advance is expected in the first quarter of 2026 and comes with a guarantee that Constellation Energy will protect taxpayer money, the DOE said.

Constellation Energy rose 3% to $349.51 on Wednesday. The benchmark S&P 500 index was up 0.3%.

Constellation Energy renamed the plant the Crane Clean Energy Center in honor of Christopher Crane, the late former CEO of its parent company, Exelon. The reactor sits adjacent to Three Mile Island Unit 2, which suffered a partial core meltdown in 1979 and immediately ceased operations.

In late 2024, Constellation inked a power purchase agreement with Microsoft that served as a catalyst to restart the plant. Bobby Hollis, Microsoft’s vice president of energy, described the deal as “a major milestone in Microsoft’s efforts to help decarbonize the grid” and “become carbon negative.”

There’s no question what the energy will be used for. Microsoft is one of the hyperscalers, or developers of massive data centers, that have looking for ways to sate the technology’s appetite for power.

Nuclear energy has been presented as a promising candidate. Supporters say nuclear energy is becoming a viable answer to unprecedented power demand, delivering continuous, carbon-free power, even as others raise concerns about safety and the disposal of nuclear waste.

The association with artificial intelligence has boosted nuclear stocks this year, sending players like Oklo sharply higher. As of Tuesday’s close, the VanEck Uranium and Nuclear ETF had gained almost 55% in 2025, outpacing gains of nearly 14% for the benchmark S&P 500.

Constellation Energy itself is largest nuclear fleet operator in the U.S., though its portfolio spans other types of power. It is no stranger to deals with hyperscalers, either. The company struck a 20-year power purchase agreement with Meta Platforms in June, which will begin in 2027.

Write to Mackenzie Tatananni at mackenzie.tatananni@barrons.com