Reclaiming Three Mile Island: Big Tech's Long-Term PPAs and Legacy Nuclear Restarts

Microsoft's $16 billion bet on a shuttered Pennsylvania reactor signals how AI infrastructure is reshaping American energy markets.

What to Know

• Microsoft signed a 20-year, $16 billion PPA to restart Three Mile Island's 837-megawatt Unit 1
• Big tech contracted more than 10 gigawatts of new nuclear capacity in a single year
• Amazon signed a 1,920-megawatt nuclear PPA with Talen Energy running through 2042
• Global data center electricity demand will grow from 460 TWh in 2024 to 1,300 TWh by 2035
• Goldman Sachs estimates 85 to 90 gigawatts of new nuclear capacity needed by 2030, but less than 10% will be available

American energy infrastructure is being reshaped by a single equation: artificial intelligence needs enormous amounts of reliable, carbon-free electricity, and the existing grid cannot provide it. Big tech companies have reached the same conclusion independently and arrived at the same answer: nuclear power is the only proven technology that delivers gigawatt-scale, round-the-clock, zero-emissions baseload generation.

Microsoft's 20-year agreement with Constellation Energy to restart Three Mile Island is the most visible example of this shift. Nearly 50 years after a partial meltdown made that Pennsylvania site synonymous with nuclear disaster, the plant is being reborn as the Crane Clean Energy Center, expected to come back online in 2028 and deliver every megawatt of its output directly to Microsoft's AI data centers.

Why Legacy Reactors Are Faster Than New Ones

Building a new nuclear plant takes decades and costs between $6,417 and $12,681 per kilowatt, compared to $1,290 per kilowatt for natural gas. Restarting an existing reactor that was shut down for economic rather than safety reasons bypasses most of that timeline and much of that cost. Constellation shut down Three Mile Island's Unit 1 in 2019 due to operating losses, not mechanical failure. Microsoft's revenue commitment through a 20-year PPA provided the financial certainty Constellation needed to justify the restart investment.

That deal structure is deliberate and replicable. A long-term PPA eliminates the market risk that made legacy reactors financially unviable in the first place. It converts an asset that could not compete on spot electricity markets into a contracted revenue stream that justifies hundreds of millions in restart capital. For American households and workers in energy-dependent regions, that structure also means new jobs, tax revenue, and grid stability that renewable-only strategies struggle to guarantee.

Amazon, Meta and the Scale of Commitment

Amazon's agreement with Talen Energy runs through 2042 and covers 1,920 megawatts of nuclear power sourced from the Susquehanna plant in Pennsylvania. Talen estimates it will deliver the full contracted volume no later than 2032, with options to extend the agreement further. Amazon has since invested more than $20 billion converting the surrounding site into a nuclear-powered AI data center campus, one of the largest single infrastructure investments in Pennsylvania's history.

Big tech nuclear power purchase agreements by company size. Created via Gemini.

Mac McFarland, President and CEO, Talen Energy

McFarland, speaking on the Amazon agreement, stated:

"Talen is well-positioned to support Amazon's energy needs as it invests further in the Commonwealth of Pennsylvania."

Meta signed a 20-year nuclear PPA with Constellation giving it 1,121 megawatts beginning in June 2027, keeping an Illinois facility online in the process. Google contracted 500 megawatts of small modular reactors from Kairos Power, with the first unit targeting 2030. Meta also issued a request for proposals targeting 1 to 4 gigawatts of additional new nuclear generation. Across all these commitments, big tech contracted more than 10 gigawatts of nuclear capacity in a single year.

What the Supply Gap Means for Ordinary Americans

Goldman Sachs estimates 85 to 90 gigawatts of new nuclear capacity would be needed to meet projected data center power demand growth by 2030. Less than 10% of that will be available globally by that date. Natural gas currently supplies over 40% of U.S. data center electricity, with renewables at 24% and nuclear at 15 to 20%. That gap ensures continued heavy reliance on fossil fuels through the decade regardless of how many PPAs get signed.

For American households, the implications are direct. Data centers competing with residential and commercial users for grid capacity push electricity prices higher. Nuclear plants operating under long-term contracts stabilize regional grid supply, which moderates the price spikes that pass through to household utility bills. Communities hosting restarted reactors gain reliable tax bases and employment that renewable projects, which require far less ongoing labor, typically cannot match.

Wrap Up

Microsoft's Three Mile Island deal is not nostalgia or symbolism. It is a financially engineered solution to a hard infrastructure problem, structured so that a shuttered reactor becomes the most reliable power source available for the world's most demanding computing workloads. Every other hyperscaler has looked at the same math and reached the same conclusion.

Ordinary Americans will feel the consequences of these decisions whether they follow them or not. Energy prices, grid reliability, job creation in industrial communities, and the long-term carbon trajectory of the electricity sector all run through the choices being made right now in corporate boardrooms and nuclear licensing offices.

Understanding who is building what, and why, is not just an energy story. It is a household budget story that will play out across utility bills for the next two decades.