Microsoft Taps Three Mile Island for AI Power: A New Chapter in Nuclear Energy and Technology In a groundbreaking move, Microsoft has announced a 20-year partnership with Constellation Energy to reopen and utilize the Three Mile Island Unit 1 nuclear reactor as a major power source for its growing AI infrastructure. This decision marks an important step in Microsoft's ongoing commitment to become carbon-negative by 2030 while addressing the rising energy demands of artificial intelligence (AI) and data centers. By turning to nuclear power, Microsoft is banking on a reliable, carbon-free energy source to help sustain its operations while cutting down on its environmental footprint. However, the announcement has not been without controversy, as it revives discussions about nuclear power’s role in the modern energy landscape, particularly given Three Mile Island’s historical baggage. This article explores the implications of Microsoft’s bold move, the potential benefits of nuclear energy for the tech industry, and the challenges that remain. The Power Demands of Artificial Intelligence Artificial intelligence, particularly machine learning and deep learning, demands an enormous amount of computational resources. As AI systems become more complex and widespread, their energy needs grow exponentially. The process of training AI models, such as natural language models like GPT-4 or image recognition systems, requires processing vast amounts of data and running countless simulations to optimize their performance. This computational intensity translates into significant electricity consumption. In fact, training a single, large AI model can require megawatts of electricity over the course of several weeks. For instance, OpenAI's GPT-3 model, trained using Microsoft’s Azure AI infrastructure, reportedly consumed the energy equivalent of several hundred households for a year during its training phase. Now, with even more advanced models like GPT-4 and DALL-E, energy consumption is likely to increase further, straining the already energy-hungry data centers that host these operations. At present, data centers globally are responsible for approximately 1% of the world's electricity consumption, with AI workloads representing a significant and growing share of that demand. According to a study by the University of Massachusetts Amherst, training some large AI models can generate as much carbon dioxide as the lifetime emissions of five average cars. This has led to calls from environmentalists and industry leaders for more sustainable solutions. While renewable energy sources, such as solar and wind, are often viewed as key to reducing the carbon footprint of data centers, these options come with limitations. Specifically, they are intermittent—solar power is available only when the sun is shining, and wind power relies on favorable wind conditions. This variability can make it difficult to ensure a constant, stable supply of electricity, which is crucial for AI infrastructure that requires uninterrupted uptime. This is where nuclear energy, with its ability to produce continuous, base-load power, becomes an attractive alternative. Unlike solar or wind, nuclear plants can run 24/7, providing consistent energy regardless of external conditions. The Legacy of Three Mile Island: A Controversial Choice The decision to reopen Three Mile Island’s Unit 1 reactor brings with it significant historical weight. The name Three Mile Island has been synonymous with nuclear energy disasters since the partial meltdown of its Unit 2 reactor in 1979, the worst nuclear accident in U.S. history. Although Unit 1 was unaffected by the meltdown and continued to operate safely until its closure in 2019, the event triggered a wave of anti-nuclear sentiment across the U.S. and the world. The 1979 incident at Three Mile Island involved a failure in the cooling system of Unit 2, leading to a partial meltdown of the reactor core. While there were no imme