It may seem that all, from risk capitalists to the media, to the Secretary of Energy of the United States, have promoted small modular reactors such as the key to unlocking a nuclear rebirth and solving climate change and the need for power of modern data centers.
On Monday, the Natural Resources Committee of the California Assembly will consider a bill to repeal a long data moratorium in nuclear plants in the state, which should be in place until there is a sustainable plan for what to do with radioactive waste. Defeated several times in the past, this bill would arise an exception for small modular reactors, or SMRs, the impossible dream of nuclear defenders.
The SMRs are typically less than 300 megawatts, compared to the 2.2 combined gigawatts of the two operating reactors of Diablo Canyon near San Luis Obispo. These smaller nuclear weapons have received so much attention in recent years, mainly because modern reactors are so expensive that the United States and Europe have stopped building anyone.
The sad truth is that Small reactors make even less sense than the greats. And Trump's tariffs only make mathematics more discouraging.
I have been analyzing nuclear energy since 1993, when I started a five -year period in the Department of Energy as the special assistant of the Deputy Secretary. I helped him supervise both the nuclear energy program and the Program for Energy Efficiency and Renewable Energy, which I executed in 1997.
So I know very well that the exaggeration is based on Movedizas sands, specifically, a seven decades failure history. As 2015 analysis Said: “The economy killed small nuclear plants in the past, and will probably continue to do so.” TO 2014 magazine article He concluded that many of these “construction support for small modular reactors” are presenting “imbued rhetorical visions of fantasy elements.”
But isn't there a ongoing nuclear rebirth? No. The Vogtle of Georgia is the only new nuclear plant that the United States has built successfully and began in recent decades. The total cost was $ 35 billion, or around $ 16 million per megavatio of generation capacity, much more than methane (natural gas) or wind and wind storage.
As such, Vogtle is “the most expensive energy plant ever built on Earth”, with an estimated electricity cost “amazingly high,” he said POWER MAGAZINE. Georgia Rate Failers each paid $ 1,000 To support this plant before they have some power, and now their bills are Increasing more than $ 200 annually.
The high cost of construction and the resulting high energy invoices explain why the nuclear participation of global energy reached its maximum point in 17% in the mid -1990s, but fell to 9.1% in 2024.
For decades, scale economies promoted reactors to grow more than 1,000 megawatts. The idea that abandoning this logic would lead to a lower cost per Megavatio is a magical thought, challenging technical plausibility, historical reality and common sense.
Even a September report of the Federal Energy Department – which finances the development SMR – modeled a cost per megavatio more than 50% higher than for large reactors. That is why there are only three operations: one in China, with a 300% overflowing cost and two in Russia, with 400% invaded. In March, a Financial Times Analysis labeled as small reactors “the most expensive energy source”.
In fact, the first SMR that the United States tried to build, by Nuscale, was canceled in 2023 after its cost was shot after $ 20 million per Megavatio, higher than Vogtle. In 2024, Bill Gates told CBS that the total cost of his Natrium reactor of 375 megawatts would be “”about $ 10 billion“Making its cost almost $ 30 million per Megavatio, almost twice Vogtle's.
All this has been developed in a historically cheap natural gas context and a rapid expansion of renewable energy sources for the generation of electricity. All that competition against nuclear energy matters: a 2023 Columbia University Report He concluded that “if the new nuclear costs end up being much higher” than $ 6.2 million per Megavatio, “it seems unlikely that the new nuclear plays a very important role, if there were, in the American energy sector.” RIP
SMRs are only one of several overvalued false promises on which the world is ready to spend hundreds of billions of dollars by 2040, including hydrogen energy and direct carbon capture of air.
But nuclear energy is overvalued original energy technology. When he was president of the Atomic Energy Commission, Lewis Strauss, Robert Downey Jr.'s character in “Oppenheimer”, predicted in 1954 that our children would enjoy nuclear energy. “too cheap for the meter. “
However, when I joined the energy department in 1993, nuclear energy costs had constantly grown for decades. Since then, the prices of the new reactors have continued to increase, and now they are the most expensive energy source. But solar energy prices, wind and battery have continued to fall, becoming the cheapest. In fact, these three technologies constitute a remarkable 93% of the US Public Services Scale. Additions of electricity generation capacity in 2025. The rest is natural gas.
China is the only country that builds many new nuclear plants in the next five years: about 35 gigawatts. Less than 1% of this projected capacity would be small reactors, while more than 95% will be reactors of more than 1,100 megawatts. Now compare all that with the 350 gigawatts of Solar and Wind China built – only in 2024.
For the United States, President Trump's erratic tariffs make small modular reactors an even more risky bet. If the US economy is reduced, also the demand for new power plants. And the twin inflation threats and higher interest rates increase the risk of excess construction costs still worse.
In addition, China, Canada and other commercial partners provide critical elements of the necessary supply chain to produce SMRs, and mass production is key to the sales argument alleging that this technology could become affordable. That logic would apply only if practically all current SMR companies fail and only one or two end up looking for mass production.
So, can we stop talking about small modular reactors as a solution to our energy needs and re -build real solutions: wind, solar energy and batteries? They are cheaper and cleaner, and actually modular.
Joseph Romm is a former interim assistant secretary and author of “The exaggeration of hydrogen: False promises and real solutions in the race to save the climate. “
