A bulldozer relocates coal intended for electricity generation at the American Electric Power coal-fired power plant in Winfield, West Virginia. (Luke Sharrett | Bloomberg | Getty Images)
The planned restart of the Three Mile Island nuclear plant marks progress for nuclear energy in the U.S., but there is a need for additional plants to meet increasing electricity demand, as highlighted by a senior nuclear official this week.
Mike Goff, acting assistant secretary for the Office of Nuclear Energy at the Department of Energy, stated that the U.S. must at least triple its nuclear fleet to meet demand, reduce carbon-dioxide emissions, and ensure the nation’s energy security.
Currently, the U.S. has the world’s largest nuclear fleet, with 94 operational reactors generating approximately 100 gigawatts of power, which accounted for over 18% of the nation’s electricity consumption in 2023.
Goff indicated that adding 200 gigawatts of nuclear power is essential, equating to approximately 200 new plants based on the current reactor size in the U.S. fleet, which averages about one gigawatt per reactor. Achieving this is a significant endeavor, emphasized Goff. In December, the U.S. led a global coalition pledging to meet this expansion goal by 2050, with major financial institutions like Goldman Sachs and Bank of America supporting the target at a recent climate conference in New York City.
Constellation Energy’s plan to restart the Three Mile Island plant by 2028 represents positive progress, according to Goff. The plant, which operated safely until its economic shutdown in 2019, will see Unit 1—unaffected by the 1979 partial meltdown—reactivated. Microsoft intends to purchase electricity from this plant to power its data centers, highlighting the substantial electricity needs of such facilities, which can consume up to a gigawatt of power. This reinforces the necessity of new reactors to provide firm, 24/7, baseload clean electricity, which nuclear energy is well-suited to supply.
However, restarting existing reactors will only cover a small fraction of the required nuclear power, Goff noted. There are limited shuttered plants available for potential restarts. Therefore, advancing new plant deployments is critical.
Former coal sites in the U.S. could serve as viable locations for new nuclear plants. Many coal utilities are phasing out as part of the clean energy transition, causing supply gaps in some areas. These coal sites, equipped with transmission lines and experienced energy industry personnel, could host up to 174 gigawatts of new nuclear capacity across 36 states, according to a Department of Energy study.
Building reactors at these coal sites could result in significant cost reductions, around 30% compared to new greenfield sites, Goff highlighted. Despite the advantages, challenges include cost overruns and lengthy construction timelines, exemplified by the expansion of the Vogtle plant in Georgia, which exceeded $30 billion and faced years of delays.
The Department of Energy study identified potential for up to 95 gigawatts of new reactors at operational and retired nuclear sites. In total, the U.S. could accommodate up to 269 gigawatts of additional nuclear power through the utilization of both coal and nuclear sites. This potential capacity hinges on the type of reactors built, with advanced, smaller reactors offering space efficiency but still years away from commercialization.
Increasing electricity demand from data centers, manufacturing, and economic electrification may drive the development of larger nuclear plants. The Three Mile Island restart alone would contribute nearly a gigawatt of power.
Maintaining and shoring up the existing nuclear fleet remains crucial. Economic shifts and increased recognition of nuclear’s carbon-free attributes, supported by the Inflation Reduction Act, could help preserve the operational viability of reactors. Goff emphasized that clean, firm, and reliable baseload electricity is increasingly valued.
Constellation’s decision to restart Three Mile Island follows plans for the Palisades plant in Michigan by Holtec International, targeting a 2025 restart. Both restarts require approval from the Nuclear Regulatory Commission, but Goff expressed confidence in their approval given adequate safety cases.
However, identifying further restart candidates may be challenging, as many plants have progressed in the decommissioning process, according to Doug True, chief nuclear officer at the Nuclear Energy Institute.