SoftBank builds massive AI data center in Ohio on former nuclear weapons site with $33B power plant

SoftBank Transforms Cold War Site Into AI Powerhouse

SoftBank is redeveloping federal land at the former Portsmouth Gaseous Diffusion Plant in Piketon, Ohio, into a massive AI data center campus that could reshape the landscape of artificial intelligence infrastructure 1

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. The Japanese investment giant's digital infrastructure arm, SB Energy, is leasing Department of Energy land to build a 10-gigawatt server farm—a scale that would make it among the largest, if not the largest, data center in the world 2

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. For context, a single gigawatt of capacity can power roughly 750,000 homes at any given moment, meaning this facility will draw enough electricity to power approximately 7.5 million homes 2

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The site itself carries historical weight. During the Cold War, the Portsmouth facility produced enriched uranium for both civilian nuclear power and the US weapons program 1

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. The US has spent billions of dollars decontaminating the site and its hundreds of buildings 3

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. According to the Department of Energy, SoftBank has committed to funding accelerated cleanup of the former uranium enrichment site 1

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, though someone else is handling the uranium cleanup costs.

Natural Gas Power and Grid Infrastructure Investment

SB Energy will construct 10 GW of new generation capacity to support the AI data center, with at least 9.2 GW coming from natural gas-fired power plants 1

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. The natural gas project, valued at approximately $33 billion, represents Japanese funding tied to the generation component and would become the biggest in the US if built, supplying the equivalent of nine nuclear reactors 2

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. The company expects the AI data center, including the chips and equipment within it, to cost $30 billion to $40 billion 2

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Rich Hossfeld, co-chief executive officer of SB Energy, said turbines for the gas project have been sourced, with the first expected to be delivered within a year and the rest coming online by the end of the decade 2

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. The turbines, capable of generating 9.2 gigawatts in total, will be installed across the region rather than at a single complex 2

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. SB Energy also plans another 800 megawatts of new capacity for the facility 2

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In a separate but critical component of this massive infrastructure project, SB Energy and AEP Ohio have struck a $4.2 billion deal to upgrade and expand electrical transmission infrastructure across Southern Ohio 1

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. Both parties claim this grid upgrade will lower utility bills for local homes and businesses 1

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. Hossfeld emphasized that equipment for the transmission work, including transformers, has already been lined up, stressing that ratepayers won't foot the bill . American Electric Power expects power to reach the site by 2029 1

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US-Japan Trade Deal and Strategic AI Competition

This public-private partnership represents a cornerstone of the US-Japan Strategic Trade and Investment Agreement announced by President Trump, with the Department of Energy confirming that the initiative includes $33.3 billion in Japanese funding 4

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. The investment is part of a broader US-Japan trade deal struck in October that committed to invest $550 billion across the United States on nuclear power, rare earth minerals, and other projects as both countries looked to reduce China's dominance over electronic components 3

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Masayoshi Son, chairman and CEO of SoftBank Group Corp, said the deal strengthens US AI leadership and helps secure capacity for energy and computing 3

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. "AI will transform every industry, and the PORTS Technology Campus will help deliver the next-generation infrastructure needed to unlock those breakthroughs," Son stated 1

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US Energy Secretary Chris Wright emphasized that the US government "is leveraging its assets—like our federal lands—to add power generation, create jobs, and ensure the United States wins the AI race" 3

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. The project is framed as consistent with President Trump's Ratepayer Protection Pledge, which aims to shield consumers from price increases driven by surging AI infrastructure demand 1

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Portsmouth Consortium and Industry Participation

SoftBank has announced a "Portsmouth Consortium" of companies and financial institutions interested in participating in the development 1

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. The consortium includes Japanese firms Hitachi, Mitsubishi Electric, Toshiba, TDK and Sumitomo Mitsui Banking, alongside US names Bechtel, Morgan Stanley, Goldman Sachs and J.P. Morgan 1

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While customers for the Ohio AI data center have yet to be announced, the company said they're coming and that they'll be involved in sourcing the chips and equipment housed within the facility 2

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. SoftBank is collaborating with OpenAI and Oracle on Stargate, an artificial intelligence infrastructure initiative aimed at building out large-scale US computing capacity to support AI, with a potential $500 billion in investment 4

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Energy Security Challenges and Environmental Concerns

The scale of this project presents significant challenges. A 10-gigawatt facility would be a tremendous undertaking given Ohio only had about 30 gigawatts of total generation as of 2024 . As an example, a 3.75-gigawatt natural gas-fired power complex in Florida—currently among the largest in the US—took years to construct and bring online in phases .

The soaring demand for artificial intelligence tools has touched off a worldwide expansion of data centers, with AI systems requiring enormous amounts of computing capacity . A backlash over the buildout is building across the US centered on the increasing costs of water and electricity, both of which data centers require in large volumes .

Environmental advocates have raised concerns about the natural gas power component. "Recommitting it to decades of new pollution is another sign of this Administration prioritizing the wrong things," said Neil Waggoner of the Sierra Club 5

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. Days before the announcement, a group of rural Ohio residents filed a petition to put a constitutional ban on mega data centers on the statewide ballot, joining a growing chorus of opponents concerned about the environmental, financial and societal costs of AI 4

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Ari Peskoe, an energy lawyer and Harvard professor, noted that electric utilities have broadly charged households and small businesses for power expenses related to serving data centers 5

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. "Perhaps this announcement signals a new way forward that charges data centers and not ratepayers for data center transmission," Peskoe said 5

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. Construction on the Portsmouth project is expected to begin this year and will create thousands of jobs while supporting research in areas such as fusion energy, quantum computing and national security applications 4

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