Microsoft's AI: US nuclear power plant to be reactivated ahead of schedule

In September last year, Microsoft surprised everyone by announcing its intention to increasingly cover its growing energy requirements for its own AI data centers with nuclear power: At the time, the software giant signed a 20-year power purchase agreement with the US utility Constellation Energy, which specializes in "CO2-neutral electricity" from nuclear facilities. The aim of the deal is to put the decommissioned TMI Unit 1 reactor at the Three Mile Island power plant back into operation by 2028. However, Constellation CEO Joe Dominguez has now indicated that the nuclear reactor could possibly be reactivated earlier.

In two years' time, i.e. 2027, "we will be ready", Dominguez told the press on Wednesday. The prerequisite is that the local grid operator in the region, Pennsylvania-New Jersey-Maryland (PJM), has reconnected the plant to the power grid. Constellation had shut down the 837-megawatt reactor in 2019. The reason: at the time, the company no longer received the necessary subsidies to compete with cheaper fossil fuels. The head of the operator now said: "We made a mistake by shutting down this power plant. But we are not here to dwell on it." It makes more sense to look to the future.

Three Mile Island gained worldwide notoriety in 1979 as the worst nuclear accident in the USA to date. A partial core meltdown occurred in reactor unit 2. As a result, Constellation shut down the affected reactor in Harrisburg (Pennsylvania) permanently. The operator left the second reactor, known as TMI Unit 1, on the grid for decades and only shut it down in 2019 for economic reasons. This week, the plant was renamed the "Crane Clean Energy Center".

The challenges of reactivation

The recommissioning of Unit 1 is not an easy process, explains The Register magazine. Although the reactor has only been out of operation for six years, the plant itself is already more than 50 years old. The turbine, generator, transformers and cooling and control systems require a comprehensive overhaul before electricity can be generated again. Approval from the US Nuclear Regulatory Commission is also required. For Constellation, however, this should in principle be a formality, as the company already operates 21 nuclear reactors in the USA.

In view of the almost insatiable demand for energy driven by the current hype surrounding generative artificial intelligence, Microsoft is not the only major cloud service provider and data center operator to have increasingly turned to nuclear energy last year. Constellation in particular is generally playing a key role here.

Meta also recently signed a 20-year offtake agreement with the Baltimore, Maryland-based energy company to expand operations at the 1.1-gigawatt Clinton Clean Energy Center nuclear power plant in DeWitt County, Illinois. This power plant was facing a similar fate to Three Mile Island Reactor Unit 1, as the state's Zero Emission Allowance program expires in 2027. Meta had previously solicited bids for one to four gigawatts of nuclear energy that could be deployed by 2030. The operator of WhatsApp, Facebook and Instagram is also relying heavily on AI. Training and operating AI software requires a lot of activity in data centers, which results in high power consumption.

Hyperscalers are increasingly relying on nuclear power

Amazon Web Services (AWS) is another hyperscaler that has invested heavily in nuclear power, spending USD 650 million to acquire a nuclear power plant from Cumulus Data. This is located next to Talen Energy's 2.5-gigawatt Susquehanna nuclear power plant in northeastern Pennsylvania. The original contract secured Amazon direct access to at least 480 megawatts of clean energy, but was revised in the spring due to concerns from local utilities about grid stability. Instead of purchasing the energy directly, Talen will now supply AWS data centers in the region with up to 1.92 gigawatts of grid power until the end of 2042.

In addition to existing nuclear power plants, small modular reactors (SMRs) have attracted a lot of interest from major cloud providers, including Google and Oracle, as a power source for data centers. These mini-nuclear power plants could further increase the output of existing reactors. However, experts assume that most of these SMRs will not be ready for launch until the early 2030s.

The new energy orientation of hyperscalers is criticized because the final disposal of nuclear waste remains unresolved and there are safety risks. In addition, nuclear power projects are associated with high costs and long construction times, which could overshadow alternative, more sustainable energy solutions. Opponents also fear that such a focus could hinder the development of truly innovative and sustainable energy sources.

(nie)