Energy

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Trump signs executive orders meant to resurrect US nuclear power

Energy, nuclear power, nuclear reactors, nuclear regulatory commission, Policy, Science / /

Plan calls for three new reactors to reach criticality in about a year.

Currently, there are no nuclear power plants scheduled for construction in the US. Everybody with plans to build one hasn’t had a reactor design approved, while nobody is planning to use any of the approved designs. This follows a period in which only three new reactors have entered service since 1990. Despite its extremely low carbon footprint, nuclear power appears to be dead in the water.

On Friday, the Trump administration issued a series of executive orders intended to revive the US nuclear industry. These include plans to streamline the reactor approval process and boost the construction of experimental reactors by the Department of Energy. But they also contain language that’s inconsistent with other administration priorities and fundamentally misunderstands the use of nuclear power. Plus, some timelines might be, shall we say, unrealistic: three new experimental reactors reaching criticality in just over a year.

Slow nukes

The heyday of nuclear plant construction in the US was in the 1970s and 80s. But the 1979 partial meltdown at the Three Mile Island plant soured public sentiment toward nuclear power. This also came at a time when nuclear plants typically generated only half of their rated capacity, making them an expensive long-term bet. As a result, plans for many plants, including some that were partially constructed, were canceled.

In this century, only four new reactors on existing plant sites have started construction, and two of those have since been cancelled due to delays and spiralling costs. The two reactors that have entered service also suffered considerable delays and cost overruns.

While safety regulations are often blamed for the construction costs, researchers who studied construction records found that many delays simply arose from workers being idled while they awaited equipment or the completion of other work on the site. This may indicate that the lack of a well-developed supply chain for reactor parts is a significant contributor. And the last major changes in safety regulations came in response to the Fukushima meltdown and explosions, which identified key vulnerabilities in traditional designs.

A large number of startups have proposed designs that should be far less prone to failure. Many of these are SMRs, or small modular reactors, which promise economies of scale by building the reactor at a central facility and then shipping it to the site of installation. But, as of yet, only a single reactor of this type has been approved in the US, and the only planned installation of that design was canceled as the projected cost of its electricity became uncompetitive.

That environment makes investing in nuclear power extremely risky on its own. However, we’re also at a time when the prices of natural gas, wind, and especially solar are incredibly low, making it challenging to justify the large up-front costs of nuclear power, along with the long lead time before it starts generating returns on those costs.

A new hope?

That’s the situation the Trump administration hopes to change, though you can question the sincerity of that effort. To start, the executive orders were issued on the Friday before a holiday weekend, typically the time reserved for news that you hope nobody pays attention to. One of the announcements also refers to nuclear power as dispatchable (meaning it can be ramped up and down quickly), which it most certainly isn’t. Finally, it touts nuclear power as avoiding the risks associated with other forms of power, “such as pollution with potentially deleterious health effects.” Elsewhere, however, the administration is eliminating pollution regulations and promoting the use of high-pollution fuels, such as coal.

Overall, the actions proposed in the new executive orders range from the fanciful to the potentially reasonable. For example, the “Reinvigorating the Nuclear Industrial Base” order calls for the development of the capacity to reprocess spent nuclear fuel to obtain useful fuel from it, a process that’s extremely expensive compared to simply mining new fuel, and would only make nuclear power less economically viable. It also calls for recommendations regarding permanent storage of any remaining waste, an issue that has remained unresolved for decades.

Mixed in with that are more sensible recommendations about ensuring the capacity to enrich isotopes to the purities needed to fuel power plants.

The order also calls for the Department of Energy (DOE) to provide financial support for the industry to boost construction of new plants, something the agency already does through a loan guarantee program. Even though those guarantees have not resulted in new construction plans in over a decade, the EO calls for the effort to result in “10 new large reactors with complete designs under construction by 2030.” While the Biden administration had approved payments to keep nuclear plants open, Trump is calling for funding to be used to reopen some plants that had been unable to operate economically—something that has not been done in the US previously. It also calls for money to go to restart construction at sites where reactors were canceled, although only two of those are less than decades old.

Similar unrealistic time scales are present in the “Deploying Advanced Nuclear Reactor Technologies” order. This is intended to encourage some of the proposed designs for SMRs and inherently safe reactors that are currently on the drawing board. It directs the Army to install one of these at a military base that will be operating within the next three years. And it directs the secretary of energy to contract with companies to build three test reactors that will sustain a nuclear reaction by July 4, 2026.

The accelerated schedule is expected to come from enabling the secretary of energy to simply ignore any aspect of the environmental review that the companies building the reactor complain about: “The Secretary shall, consistent with applicable law, use all available authorities to eliminate or expedite the Department’s environmental reviews for authorizations, permits, approvals, leases, and any other activity requested by an applicant or potential applicant.”

Regulatory reform

The other big executive order targets the Nuclear Regulatory Commission (NRC), which approves license designs. The order blames this on how the NRC is structured: “The NRC charges applicants by the hour to process license applications, with prolonged timelines that maximize fees while throttling nuclear power development.”

It also criticizes the commission’s regulations as being based on the idea that there is no safe level of exposure to radiation, though it provides no evidence that the idea is wrong. This is said to result in regulations that attempt to lower exposures below those caused by a natural environment.

The order attempts to accelerate the approval process enough to ensure that the US goes from 100 GW of generating capacity to 400 GW by 2050. This is largely done by setting hard time limits on the approval process through consultations with DOGE, including a limit of 18 months for approval of new nuclear plants. It also calls for the adoption of “science-based radiation limits,” claiming that flaws with existing limits had been discussed earlier—even though the earlier discussion made no mention of scientific flaws.

In keeping with plans for mass production of modular reactors, the order also calls for a single certification process for these designs, focusing solely on site differences once the general reactor design is accepted as safe.

Overall, there are some reasonable ideas scattered throughout the executive orders (though whether their implementation ends up being reasonable is questionable, especially given DOGE’s involvement). But the majority of them are based on the idea that regulation is the primary reason for nuclear energy’s atrophy in the US.

The reality is that an underdeveloped supply chain and unfavorable economics are far larger factors. It’s difficult to justify investing in a plant that might take a decade to start selling power when the up-front costs of solar are far smaller, and it can start producing power while still under construction. The most likely way to see a nuclear resurgence in the US is for the government to pay for the plants itself. There’s a small bit of that here, in the call for the DOE to fund the construction of experimental reactors at third-party sites. But it’s not enough to significantly shift the trajectory of US nuclear power.

Photo of John Timmer

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

Trump signs executive orders meant to resurrect US nuclear power Read More »

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US solar keeps surging, generating more power than hydro in 2025

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Under those circumstances, the rest of the difference will be made up for with fossil fuels. Running counter to recent trends, the use of natural gas dropped during the first three months of 2025. This means that the use of coal rose nearly as quickly as demand, up by 23 percent compared to the same time period in 2024.

Despite the rise in coal use, the fraction of carbon-free electricity held steady year over year, with wind/solar/hydro/nuclear accounting for 43 percent of all power put on the US grid. That occurred despite small drops in nuclear and hydro production.

Solar power also passed a key milestone in 2025, although it requires digging through the statistics to realize it. In terms of power on the grid, there was less solar than hydro. But the Energy Information Agency also estimates the production from small-scale solar, like the kind you’d find on people’s roofs. Some of this never enters the grid and instead simply offsets demand locally (in that it gets used by the house that sits beneath the panels). If you combine the TW-hr produced by small- and grid-scale solar, however, they surpass the production from hydropower by a significant margin.

This surge in solar comes on top of a 30 percent increase in production the year prior. The growth curve is clearly not slowing down.

That dynamic is also not likely to change immediately in response to cuts to tax breaks for renewable power that were part of the budget package passed by the House of Representatives on Thursday, and not only because some Republican senators might object to budget changes that will harm their states. Solar power in most areas is now cheaper than alternatives, even without subsidies, and any power plant (renewable or otherwise) will likely see its costs rise due to the tariff environment. Finally, the tax breaks don’t expire immediately, and most power plant construction requires significant advanced planning.

All of those factors should continue the solar boom for at least a couple more years before all of the expected changes apply the brakes.

US solar keeps surging, generating more power than hydro in 2025 Read More »

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Trump admin lifts hold on offshore wind farm, doesn’t explain why

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On Monday, however, the company announced that the hold had been lifted and construction would resume. But as with the hold itself, the reasons for its end remain mysterious. The Bureau of Ocean Energy Management page for the project was only updated with a new letter on Tuesday. That letter indicates a review of its approval is ongoing, but construction can resume during the review.

The Department of the Interior has not addressed the change and has not responded to a request for comment. A post by Interior Secretary Burgum doesn’t mention Empire Wind but does suggest the governor of New York will approve a pipeline: “I am encouraged by Governor Hochul’s comments about her willingness to move forward on critical pipeline capacity.”

That suggests there was a deal that allowed Empire Wind to resume construction in return for a pipeline for fossil fuels. The New York Times suggests that this is a reference to the proposed Constitution Pipeline, which was planned to move natural gas from Pennsylvania to eastern New York but was cancelled in 2020 due to state opposition.

However, Governor Kathy Hochul has not commented about a willingness to move forward with any pipelines. Instead, Hochul’s statement on Empire Wind is very vague, saying that she “reaffirmed that New York will work with the Administration and private entities on new energy projects that meet the legal requirements under New York law.”

So while it’s good news that construction on Empire Wind has restarted, the whole process has been problematic, driven by apparently arbitrary decisions that the government has refused to justify.

Trump admin lifts hold on offshore wind farm, doesn’t explain why Read More »

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Spain is about to face the challenge of a “black start”

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Local conditions

While the grids in Spain and Portugal are connected to each other, they have limited connections to elsewhere. The only sources of external power to the grid come from France and Morocco, which are small connections, but they could be used to help black start some plants. Both blacked-out countries have significant hydropower, with Spain seeing it cover 10 percent of its demand and Portugal 25 percent. That’s useful because hydro plants need very little in the way of an external power supply to start operating.

Beyond that, both countries have invested heavily in renewables, with Portugal supplying about half of its power from wind and hydro, having closed its last coal plant in 2021. Spain receives about 40 percent of its power from renewables at present.

Solar is not an ideal power source for black-starting the grid, given that it’s unavailable for a significant chunk of the day. But solar panels produce direct current, with electronic systems matching it to the alternating current of the grid. With the right electronics, it can play a key role in keeping frequencies stable as grid segments are repowered. In productive areas, wind can provide black start power to other plants, and doesn’t need much external power to begin operations. It’s unclear, however, whether the local wind hardware is equipped for black starts, or if the local weather will cooperate (a quick check of the weather in various cities suggests it’s relatively calm there).

Batteries have the potential to be incredibly helpful, since they also provide direct current that can be converted to any frequency needed, and so used for both starting up power plants or for frequency stabilization as segments of the grid are brought back online. Unfortunately, neither country has installed much grid-scale battery hardware yet. That’s expected to change over the next few years in parallel with dramatically expanded solar power. But, at the moment, batteries will not be a huge help.

Regardless of how precisely the grid operators manage to handle this task in Spain and Portugal, they face a monumental challenge at the moment. If you’re seeing estimates of several days for the restoration of power, it’s because failing to meet this challenge will leave things back in the state they’re in now.

Spain is about to face the challenge of a “black start” Read More »

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US Interior secretary orders offshore wind project shut down

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It’s notable that this hold comes despite Trump’s executive order explicitly stating, “Nothing in this withdrawal [of future leasing] affects rights under existing leases in the withdrawn areas.”

GAO undercuts the message

The order alleged there were “various alleged legal deficiencies underlying the Federal Government’s leasing and permitting of onshore and offshore wind projects, the consequences of which may lead to grave harm.” In response to those allegations, the Government Accountability Office began an evaluation of the Department of the Interior’s activities in overseeing offshore wind development. The results of that were made public on Monday.

And the report only found minor issues. Its primary recommendations are that Interior improve its consultations with leaders of tribal communities that may be impacted by wind development and boost “incorporation of Indigenous knowledge.” The GAO also thinks that Interior should improve its methods of getting input from the fishing industry. The report also acknowledges that there are uncertainties about everything from invasive species to the turbines’ effect on navigational radar but says these will vary based on a wind farm’s site, size, and other features, and we’ll only have a clearer picture once we have built more of them.

Notably, it says that wind farm development has had no effect on the local whale population, a popular Republican criticism of offshore wind.

Trump’s animosity toward wind power has a long history, so it’s unlikely that this largely positive report will do much to get the hold on leasing lifted. In reality, however, the long-term uncertainty about offshore wind in the US will probably block new developments until the end of Trump’s time in office. Offshore wind companies have budgeted based on tax incentives in the Inflation Reduction Act, and the administration has suggested they may revoke those in future budgets. And the move by Burgum means that, even if a company clears all the leasing and improvement hurdles, the government may shut down a project for seemingly arbitrary reasons.

US Interior secretary orders offshore wind project shut down Read More »

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The UK got rid of coal—where’s it going next?

Energy, energy policy, renewable energy, Science, Sustainability / /

Clean, but not fully green

The UK has transitioned to a lower-emission grid. Now comes the hard part.

With the closure of its last coal-fired power plant, Ratcliffe-on-Soar, on September 30, 2024, the United Kingdom has taken a significant step toward its net-zero goals. It’s no small feat to end the 142-year era of coal-powered electricity in the country that pioneered the Industrial Revolution. Yet the UK’s journey away from coal has been remarkably swift, with coal generation plummeting from 40 percent of the electricity mix in 2012 to just two percent in 2019, and finally to zero in 2024.

As of 2023, approximately half of UK electricity generation comes from zero-carbon sources, with natural gas serving as a transitional fuel. The UK aims to cut greenhouse gas emissions by 42 percent to 48 percent by 2027 and achieve net-zero by 2050. The government set a firm target to generate all of its electricity from renewable sources by 2040, emphasizing offshore wind and solar energy as the keys.

What will things look like in the intervening years, which will lead us from today to net-zero? Everyone’s scenario, even when based in serious science, boils down to a guessing game. Yet some things are more certain than others, the most important of these factors being the ones that are on solid footing beneath all of the guesswork.

Long-term goals

The closure of all UK coal-fired power stations in 2024 marked a crucial milestone in the nation’s decarbonization efforts. Coal was once the dominant source of electricity generation, but its contribution to greenhouse gas emissions made it a primary target for phase-out. The closure of these facilities has significantly reduced the UK’s carbon footprint and paved the way for cleaner energy sources.

With transition from coal, natural gas is set to play a crucial role as a “transition fuel.” The government’s “British Energy Security Strategy” argued that gas must continue to be an important part of the energy mix. It positioned gas as the “glue” that holds the electricity system together during the transition. Even the new Starmer government recognizes that, as the country progresses towards net-zero by 2050, the country may still use about a quarter of the gas it currently consumes.

Natural gas emits approximately half as much carbon dioxide as coal when combusted, making it a cleaner alternative during the shift to renewable energy sources. In 2022, natural gas accounted for around 40 percent of the UK’s electricity generation, while coal contributed less than two percent. This transition phase is deemed by the government to be essential as the country ramps up the capacity of renewable energy sources, particularly wind and solar power, to fill gaps left by the reduction of fossil fuels. The government aims to phase out natural gas that’s not coupled with carbon capture by 2035, but in the interim, it serves as a crucial bridge, ensuring energy security while reducing overall emissions.

But its role is definitely intended to be temporary; the UK’s long-term energy goal is to reduce reliance on all fossil fuels (starting with imported supplies), pushing for a rapid transition to cleaner, domestic sources of energy.

The government’s program has five primary targets:

  • Fully decarbonizing the power system (2035)
  • Ending the sale of new petrol and diesel cars (2035)
  • Achieving “Jet Zero” – net-zero UK aviation emissions (2050)
  • Creating 30,000 hectares of new woodland per year (2025)
  • Generating 50 percent of its total electricity from renewable sources by 2030

Offshore wind energy has emerged as this strategy’s key component, with significant investments being made in new wind farms. Favorable North Sea wind conditions have immense potential. In recent years, a surge in offshore wind investment has translated into several large-scale developments in advanced planning stages or now under construction.

The government has set a target to increase offshore wind capacity to 50 GW by 2030, up from around 10 GW currently. This initiative is supported by substantial financial commitments from both the public and private sectors. Recent investment announcements underscore the UK’s commitment to this goal and the North Sea’s central role in it. In 2023, the government announced plans to invest $25 billion (20 billion British pounds) in carbon capture and offshore wind projects in the North Sea over the next two decades. This investment is expected to create up to 50,000 jobs and help position the UK as a leader in clean energy technologies.

This was part of investments totaling over $166 million (133 million pounds) to support the development of new offshore wind farms, which are expected to create thousands of jobs and stimulate local economies.

In 2024, further investments were announced to support the expansion of offshore wind capacity. The government committed to holding annual auctions for new offshore wind projects to meet its goal of quadrupling offshore wind capacity by 2030. These investments are part of a broader strategy to leverage the UK’s expertise in offshore industries and transition the North Sea from an oil and gas hub to a clean-energy powerhouse.

Offshore wind

As the UK progresses toward its net-zero target, it faces both challenges and opportunities. While significant progress has been made in decarbonizing the power sector, the national government’s Climate Change Committee has noted that emissions reductions need to accelerate in other sectors, particularly agriculture, land use, and waste. However, with continued investment in renewable energy and supportive policies, the UK is positioning itself to become a leader in the global transition to a low-carbon economy.

Looking ahead, 2025 promises to be a landmark year for the UK’s green energy sector, with further investment announcements and projects in the pipeline.

The Crown Estate, which manages the seabed around England, Wales, and Northern Ireland, has made significant strides in facilitating new leases for offshore wind development. In 2023, the Crown Estate Scotland announced the successful auction of seabed leases for new offshore wind projects, totaling a capacity of 5 gigawatts. And in 2024, the government plans to hold its next major leasing round, which could see the deployment of an additional 7 GW of offshore wind capacity.

The UK government also approved plans for the Dogger Bank Wind Farm, which will be the world’s largest offshore wind farm when completed. Located off the coast of Yorkshire, this massive project will ultimately generate enough electricity to power millions of homes. Dogger is a joint venture linking SSE Renewables, Equinor, and Vattenfall.

This is in line with the government’s broader strategy to enhance energy independence and resilience, particularly in light of the geopolitical uncertainties affecting global energy markets. The UK’s commitment to renewable energy is not merely an environmental imperative; it is also an economic opportunity. By harnessing the vast potential of the North Sea, the UK aims not only to meet its net-zero targets but also to drive economic growth and job creation in the green energy sector, ensuring a sustainable future for generations to come.

Recognizing wind’s importance, the UK government launched a 2024 consultation on plans to develop a new floating wind energy sector.

The transition to a greener economy is projected to create up to 400,000 jobs by 2030 across various sectors, including manufacturing, installation, and maintenance of renewable energy technologies.

Its growing offshore wind industry is expected to attract billions in investment, solidifying the UK’s position as a leader in the global green energy market. The government’s commitment to offshore wind development, underscored by substantial investments in 2023 and anticipated announcements for 2024, signals a robust path forward.

Moving away from gas

Still, the path ahead remains challenging, requiring a multifaceted approach that balances economic growth, energy security, and environmental sustainability.

With the transition from coal, natural gas is now poised to play the central role as a bridge fuel. While natural gas emits fewer greenhouse gases than coal, it is still a fossil fuel and contributes to carbon emissions. However, in the short term, natural gas can help maintain energy security and provide a reliable source of electricity during periods of low renewable energy output. Additionally, natural gas can be used to produce hydrogen, potentially coupled with carbon capture, enabling a clean energy carrier that can be integrated into the existing energy infrastructure.

To support the country’s core clean energy goals, the government is implementing specific initiatives, although the pace has been quite uneven. The UK Emissions Trading Scheme (ETS) is being strengthened to incentivize industrial decarbonization. The government has also committed to investing in key green industries alongside offshore wind: carbon capture, usage and storage (CCUS), and nuclear energy.

Combined, these should allow the UK to limit its use of natural gas and capture the emissions associated with any remaining fossil fuel use.

While both countries are relying heavily on wind power, the UK’s energy-generation transformations are different from Germany’s. While both governments push to make some progress on the path to net-zero carbon emissions, their approaches and timelines differ markedly.

Energiewende, Germany’s energy transition, is characterized by what some critics consider to be overly ambitious goals for achieving net greenhouse gas neutrality by 2045. Those critics think that the words don’t come close to matching the required levels of either government or private sector financial commitment. Together with the Bundestag, the chancellor has set interim targets to reduce emissions by 65 percent by 2030 and 88 percent by 2040 (both compared to 1990 levels). Germany’s energy mix is heavily reliant on renewables, with a goal of sourcing 80 percent of its electricity from renewable energy by 2030—and achieving 100 percent by 2035.

However, Germany has faced challenges due to continued reliance on coal and natural gas, which made it difficult to reach its emissions goals.

The UK, however, appears to be ahead in terms of immediate reductions in coal use and the integration of renewables into its energy mix. Germany’s path is more complex, as it balances its energy transition with energy security concerns, particularly in light of how Russia’s war affects gas supplies.

The UK got rid of coal—where’s it going next? Read More »

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US‘s wind and solar will generate more power than coal in 2024

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We can expect next year’s numbers to also show a large growth in solar production, as the EIA says that the US saw record levels of new solar installations in 2024, with 37 gigawatts of new capacity. Since some of that came online later in the year, it’ll produce considerably more power next year. And, in its latest short-term energy analysis, the EIA expects to see over 20 GW of solar capacity added in each of the next two years. New wind capacity will push that above 30 GW of renewable capacity each of these years.

A bar chart, with the single largest bar belonging to solar energy.

The past few years of solar installations have led to remarkable growth in its power output. Credit: John Timer

That growth will, it’s expected, more than offset continued growth in demand, although that growth is expected to be somewhat slower than we saw in 2024. It also predicts about 15 GW of coal will be removed from the grid during those two years. So, even without any changes in policy, we’re likely to see a very dynamic grid landscape over the next few years.

But changes in policy are almost certainly on the way. The flurry of executive orders issued by the Trump administration includes a number of energy-related changes. These include defining “energy” in a way that excludes wind and solar, an end to offshore wind leasing and the threat to terminate existing leases, and a re-evaluation of the allocation of funds from some of the Biden administration’s energy-focused laws.

In essence, this sets up a clash among economics, state policies, and federal policy. Even without any subsidies, wind and solar are the cheapest ways to produce electricity in much of the US. In addition, a number of states have mandates that will require the use of more renewable energy. At the same time, the permitting process for the plants and their grid connections will often require approvals at the federal level, and it appears to be official policy to inhibit renewables when possible. And a number of states are also making attempts to block new renewable power installations.

It’s going to be a challenging period for everyone involved in renewable energy.

US‘s wind and solar will generate more power than coal in 2024 Read More »

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Coal likely to go away even without EPA’s power plant regulations

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Set to be killed by Trump, the rules mostly lock in existing trends.

In April last year, the Environmental Protection Agency released its latest attempt to regulate the carbon emissions of power plants under the Clean Air Act. It’s something the EPA has been required to do since a 2007 Supreme Court decision that settled a case that started during the Clinton administration. The latest effort seemed like the most aggressive yet, forcing coal plants to retire or install carbon capture equipment and making it difficult for some natural gas plants to operate without capturing carbon or burning green hydrogen.

Yet, according to a new analysis published in Thursday’s edition of Science, they wouldn’t likely have a dramatic effect on the US’s future emissions even if they were to survive a court challenge. Instead, the analysis suggests the rules serve more like a backstop to prevent other policy changes and increased demand from countering the progress that would otherwise be made. This is just as well, given that the rules are inevitably going to be eliminated by the incoming Trump administration.

A long time coming

The net result of a number of Supreme Court decisions is that greenhouse gasses are pollutants under the Clean Air Act, and the EPA needed to determine whether they posed a threat to people. George W. Bush’s EPA dutifully performed that analysis but sat on the results until its second term ended, leaving it to the Obama administration to reach the same conclusion. The EPA went on to formulate rules for limiting carbon emissions on a state-by-state basis, but these were rapidly made irrelevant because renewable power and natural gas began displacing coal even without the EPA’s encouragement.

Nevertheless, the Trump administration replaced those rules with ones designed to accomplish even less, which were thrown out by a court just before Biden’s inauguration. Meanwhile, the Supreme Court stepped in to rule on the now-even-more-irrelevant Obama rules, determining that the EPA could only regulate carbon emissions at the level of individual power plants rather than at the level of the grid.

All of that set the stage for the latest EPA rules, which were formulated by the Biden administration’s EPA. Forced by the court to regulate individual power plants, the EPA allowed coal plants that were set to retire within the decade to continue to operate as they have. Anything that would remain operational longer would need to either switch fuels or install carbon capture equipment. Similarly, natural gas plants were regulated based on how frequently they were operational; those that ran less than 40 percent of the time could face significant new regulations. More than that, and they’d have to capture carbon or burn a fuel mixture that is primarily hydrogen produced without carbon emissions.

While the Biden EPA’s rules are currently making their way through the courts, they’re sure to be pulled in short order by the incoming Trump administration, making the court case moot. Nevertheless, people had started to analyze their potential impact before it was clear there would be an incoming Trump administration. And the analysis is valuable in the sense that it will highlight what will be lost when the rules are eliminated.

By some measures, the answer is not all that much. But the answer is also very dependent upon whether the Trump administration engages in an all-out assault on renewable energy.

Regulatory impact

The work relies on the fact that various researchers and organizations have developed models to explore how the US electric grid can economically meet demand under different conditions, including different regulatory environments. The researchers obtained nine of them and ran them with and without the EPA’s proposed rules to determine their impact.

On its own, eliminating the rules has a relatively minor impact. Without the rules, the US grid’s 2040 carbon dioxide emissions would end up between 60 and 85 percent lower than they were in 2005. With the rules, the range shifts to between 75 and 85 percent—in essence, the rules reduce the uncertainty about the outcomes that involve the least change.

That’s primarily because of how they’re structured. Mostly, they target coal plants, as these account for nearly half of the US grid’s emissions despite supplying only about 15 percent of its power. They’ve already been closing at a rapid clip, and would likely continue to do so even without the EPA’s encouragement.

Natural gas plants, the other major source of carbon emissions, would primarily respond to the new rules by operating less than 40 percent of the time, thus avoiding stringent regulation while still allowing them to handle periods where renewable power underproduces. And we now have a sufficiently large fleet of natural gas plants that demand can be met without a major increase in construction, even with most plants operating at just 40 percent of their rated capacity. The continued growth of renewables and storage also contributes to making this possible.

One irony of the response seen in the models is that it suggests that two key pieces of the Inflation Reduction Act (IRA) are largely irrelevant. The IRA provides benefits for the deployment of carbon capture and the production of green hydrogen (meaning hydrogen produced without carbon emissions). But it’s likely that, even with these credits, the economics wouldn’t favor the use of these technologies when alternatives like renewables plus storage are available. The IRA also provides tax credits for deploying renewables and storage, pushing the economics even further in their favor.

Since not a lot changes, the rules don’t really affect the cost of electricity significantly. Their presence boosts costs by an estimated 0.5 to 3.7 percent in 2050 compared to a scenario where the rules aren’t implemented. As a result, the wholesale price of electricity changes by only two percent.

A backstop

That said, the team behind the analysis argues that, depending on other factors, the rules could play a significant role. Trump has suggested he will target all of Biden’s energy policies, and that would include the IRA itself. Its repeal could significantly slow the growth of renewable energy in the US, as could continued problems with expanding the grid to incorporate new renewable capacity.

In addition, the US is seeing demand for electricity rise at a faster pace in 2023 than in the decade leading up to it. While it’s still unclear whether that’s a result of new demand or simply weather conditions boosting the use of electricity in heating and cooling, there are several factors that could easily boost the use of electricity in coming years: the electrification of transport, rising data center use, and the electrification of appliances and home heating.

Should these raise demand sufficiently, then it could make continued coal use economical in the absence of the EPA rules. “The rules … can be viewed as backstops against higher emissions outcomes under futures with improved coal plant economics,” the paper suggests, “which could occur with higher demand, slower renewables deployment from interconnection and permitting delays, or higher natural gas prices.”

And it may be the only backstop we have. The report also notes that a number of states have already set aggressive emissions reduction targets, including some for net zero by 2050. But these don’t serve as a substitute for federal climate policy, given that the states that are taking these steps use very little coal in the first place.

Science, 2025. DOI: 10.1126/science.adt5665  (About DOIs).

Photo of John Timmer

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

Coal likely to go away even without EPA’s power plant regulations Read More »

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Amazon joins Google in investing in small modular nuclear power

Amazon, AWS, Biz & IT, carbon emissions, Energy, nuclear energy, Science, small modular nuclear reactors / /

Small nukes is good nukes?

What’s with the sudden interest in nuclear power among tech titans?

Diagram of a reactor and its coolant system. There are two main components, the reactor itself, which has a top-to-bottom flow of fuel pellets, and the boiler, which receives hot gas from the reactor and uses it to boil water.

Fuel pellets flow down the reactor (left), as gas transfer heat to a boiler (right). Credit: X-energy

On Tuesday, Google announced that it had made a power purchase agreement for electricity generated by a small modular nuclear reactor design that hasn’t even received regulatory approval yet. Today, it’s Amazon’s turn. The company’s Amazon Web Services (AWS) group has announced three different investments, including one targeting a different startup that has its own design for small, modular nuclear reactors—one that has not yet received regulatory approval.

Unlike Google’s deal, which is a commitment to purchase power should the reactors ever be completed, Amazon will lay out some money upfront as part of the agreements. We’ll take a look at the deals and technology that Amazon is backing before analyzing why companies are taking a risk on unproven technologies.

Money for utilities and a startup

Two of Amazon’s deals are with utilities that serve areas where it already has a significant data center footprint. One of these is Energy Northwest, which is an energy supplier that sends power to utilities in the Pacific Northwest. Amazon is putting up the money for Energy Northwest to study the feasibility of adding small modular reactors to its Columbia Generating Station, which currently houses a single, large reactor. In return, Amazon will get the right to purchase power from an initial installation of four small modular reactors. The site could potentially support additional reactors, which Energy Northwest would be able to use to meet demands from other users.

The deal with Virginia’s Dominion Energy is similar in that it would focus on adding small modular reactors to Dominion’s existing North Anna Nuclear Generating Station. But the exact nature of the deal is a bit harder to understand. Dominion says the companies will “jointly explore innovative ways to advance SMR development and financing while also mitigating potential cost and development risks.”

Should either or both of these projects go forward, the reactor designs used will come from a company called X-energy, which is involved in the third deal Amazon is announcing. In this case, it’s a straightforward investment in the company, although the exact dollar amount is unclear (the company says Amazon is “anchoring” a $500 million round of investments). The money will help finalize the company’s reactor design and push it through the regulatory approval process.

Small modular nuclear reactors

X-energy is one of several startups attempting to develop small modular nuclear reactors. The reactors all have a few features that are expected to help them avoid the massive time and cost overruns associated with the construction of large nuclear power stations. In these small reactors, the limited size allows them to be made at a central facility and then be shipped to the power station for installation. This limits the scale of the infrastructure that needs to be built in place and allows the assembly facility to benefit from economies of scale.

This also allows a great deal of flexibility at the installation site, as you can scale the facility to power needs simply by adjusting the number of installed reactors. If demand rises in the future, you can simply install a few more.

The small modular reactors are also typically designed to be inherently safe. Should the site lose power or control over the hardware, the reactor will default to a state where it can’t generate enough heat to melt down or damage its containment. There are various approaches to achieving this.

X-energy’s technology is based on small, self-contained fuel pellets called TRISO particles for TRi-structural ISOtropic. These contain both the uranium fuel and a graphite moderator and are surrounded by a ceramic shell. They’re structured so that there isn’t sufficient uranium present to generate temperatures that can damage the ceramic, ensuring that the nuclear fuel will always remain contained.

The design is meant to run at high temperatures and extract heat from the reactor using helium, which is used to boil water and generate electricity. Each reactor can produce 80 megawatts of electricity, and the reactors are designed to work efficiently as a set of four, creating a 320 MW power plant. As of yet, however, there are no working examples of this reactor, and the design hasn’t been approved by the Nuclear Regulatory Commission.

Why now?

Why is there such sudden interest in small modular reactors among the tech community? It comes down to growing needs and a lack of good alternatives, even given the highly risky nature of the startups that hope to build the reactors.

It’s no secret that data centers require enormous amounts of energy, and the sudden popularity of AI threatens to raise that demand considerably. Renewables, as the cheapest source of power on the market, would be one way of satisfying that growth, but they’re not ideal. For one thing, the intermittent nature of the power they supply, while possible to manage at the grid level, is a bad match for the around-the-clock demands of data centers.

The US has also benefitted from over a decade of efficiency gains keeping demand flat despite population and economic growth. This has meant that all the renewables we’ve installed have displaced fossil fuel generation, helping keep carbon emissions in check. Should newly installed renewables instead end up servicing rising demand, it will make it considerably more difficult for many states to reach their climate goals.

Finally, renewable installations have often been built in areas without dedicated high-capacity grid connections, resulting in a large and growing backlog of projects (2.6 TW of generation and storage as of 2023) that are stalled as they wait for the grid to catch up. Expanding the pace of renewable installation can’t meet rising server farm demand if the power can’t be brought to where the servers are.

These new projects avoid that problem because they’re targeting sites that already have large reactors and grid connections to use the electricity generated there.

In some ways, it would be preferable to build more of these large reactors based on proven technologies. But not in two very important ways: time and money. The last reactor completed in the US was at the Vogtle site in Georgia, which started construction in 2009 but only went online this year. Costs also increased from $14 billion to over $35 billion during construction. It’s clear that any similar projects would start generating far too late to meet the near-immediate needs of server farms and would be nearly impossible to justify economically.

This leaves small modular nuclear reactors as the least-bad option in a set of bad options. Despite many startups having entered the space over a decade ago, there is still just a single reactor design approved in the US, that of NuScale. But the first planned installation saw the price of the power it would sell rise to the point where it was no longer economically viable due to the plunge in the cost of renewable power; it was canceled last year as the utilities that would have bought the power pulled out.

The probability that a different company will manage to get a reactor design approved, move to construction, and manage to get something built before the end of the decade is extremely low. The chance that it will be able to sell power at a competitive price is also very low, though that may change if demand rises sufficiently. So the fact that Amazon is making some extremely risky investments indicates just how worried it is about its future power needs. Of course, when your annual gross profit is over $250 billion a year, you can afford to take some risks.

Photo of John Timmer

John is Ars Technica’s science editor. He has a Bachelor of Arts in Biochemistry from Columbia University, and a Ph.D. in Molecular and Cell Biology from the University of California, Berkeley. When physically separated from his keyboard, he tends to seek out a bicycle, or a scenic location for communing with his hiking boots.

Amazon joins Google in investing in small modular nuclear power Read More »

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For the first time since 1882, UK will have no coal-fired power plants

coal power, Energy, renewable energy, Science, Sustainability, UK / /

Into the black —

A combination of government policy and economics spells the end of UK’s coal use.

–

Image of cooling towers and smoke stacks against a dusk sky.

Enlarge / The Ratcliffe-on-Soar plant is set to shut down for good today.

On Monday, the UK will see the closure of its last operational coal power plant, Ratcliffe-on-Soar, which has been operating since 1968. The closure of the plant, which had a capacity of 2,000 megawatts, will bring an end to the history of the country’s coal use, which started with the opening of the first coal-fired power station in 1882. Coal played a central part in the UK’s power system in the interim, in some years providing over 90 percent of its total electricity.

But a number of factors combined to place coal in a long-term decline: the growth of natural gas-powered plants and renewables, pollution controls, carbon pricing, and a government goal to hit net-zero greenhouse gas emissions by 2050.

From boom to bust

It’s difficult to overstate the importance of coal to the UK grid. It was providing over 90 percent of the UK’s electricity as recently as 1956. The total amount of power generated continued to climb well after that, reaching a peak of 212 terawatt hours of production by 1980. And the construction of new coal plants was under consideration as recently as the late 2000s. According to the organization Carbon Brief’s excellent timeline of coal use in the UK, continuing the use of coal with carbon capture was given consideration.

But several factors slowed the use of fuel ahead of any climate goals set out by the UK, some of which have parallels to the US’s situation. The European Union, which included the UK at the time, instituted new rules to address acid rain, which raised the cost of coal plants. In addition, the exploitation of oil and gas deposits in the North Sea provided access to an alternative fuel. Meanwhile, major gains in efficiency and the shift of some heavy industry overseas cut demand in the UK significantly.

Through their effect on coal use, these changes also lowered employment in coal mining. The mining sector has sometimes been a significant force in UK politics, but the decline of coal reduced the number of people employed in the sector, reducing its political influence.

These had all reduced the use of coal even before governments started taking any aggressive steps to limit climate change. But, by 2005, the EU implemented a carbon trading system that put a cost on emissions. By 2008, the UK government adopted national emissions targets, which have been maintained and strengthened since then by both Labour and Conservative governments up until Rishi Sunak, who was voted out of office before he had altered the UK’s trajectory. What started as a pledge for a 60 percent reduction in greenhouse gas emissions by 2050 now requires the UK to hit net zero by that date.

Renewables, natural gas, and efficiency have all squeezed coal off the UK grid.

Enlarge / Renewables, natural gas, and efficiency have all squeezed coal off the UK grid.

These have included a floor on the price of carbon that ensures fossil-powered plants pay a cost for emissions that’s significant enough to promote the transition to renewables, even if prices in the EU’s carbon trading scheme are too low for that. And that transition has been rapid, with the total generations by renewables nearly tripling in the decade since 2013, heavily aided by the growth of offshore wind.

How to clean up the power sector

The trends were significant enough that, in 2015, the UK announced that it would target the end of coal in 2025, despite the fact that the first coal-free day on the grid wouldn’t come until two years after. But two years after that landmark, however, the UK was seeing entire weeks where no coal-fired plants were active.

To limit the worst impacts of climate change, it will be critical for other countries to follow the UK’s lead. So it’s worthwhile to consider how a country that was committed to coal relatively recently could manage such a rapid transition. There are a few UK-specific factors that won’t be possible to replicate everywhere. The first is that most of its coal infrastructure was quite old—Ratcliffe-on-Soar dates from the 1960s—and so it required replacement in any case. Part of the reason for its aging coal fleet was the local availability of relatively cheap natural gas, something that might not be true elsewhere, which put economic pressure on coal generation.

Another key factor is that the ever-shrinking number of people employed by coal power didn’t exert significant pressure on government policies. Despite the existence of a vocal group of climate contrarians in the UK, the issue never became heavily politicized. Both Labour and Conservative governments maintained a fact-based approach to climate change and set policies accordingly. That’s notably not the case in countries like the US and Australia.

But other factors are going to be applicable to a wide variety of countries. As the UK was moving away from coal, renewables became the cheapest way to generate power in much of the world. Coal is also the most polluting source of electrical power, providing ample reasons for regulation that have little to do with climate. Forcing coal users to pay even a fraction of its externalized costs on human health and the environment serve to make it even less economical compared to alternatives.

If these later factors can drive a move away from coal despite government inertia, then it can pay significant dividends in the fight to limit climate change. Inspired in part by the success in moving its grid off coal, the new Labour government in the UK has moved up its timeline for decarbonizing its power sector to 2030 (up from the previous Conservative government’s target of 2035).

For the first time since 1882, UK will have no coal-fired power plants Read More »

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US grid adds batteries at 10x the rate of natural gas in first half of 2024

batteries, Energy, green, natural gas, nuclear, renewable energy, Science, solar, Sustainability, Wind / /

In transition —

By year’s end, 96 percent of the US’s grid additions won’t add carbon to the atmosphere.

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US grid adds batteries at 10x the rate of natural gas in first half of 2024

While solar power is growing at an extremely rapid clip, in absolute terms, the use of natural gas for electricity production has continued to outpace renewables. But that looks set to change in 2024, as the US Energy Information Agency (EIA) has run the numbers on the first half of the year and found that wind, solar, and batteries were each installed at a pace that dwarfs new natural gas generators. And the gap is expected to get dramatically larger before the year is over.

Solar, batteries booming

According to the EIA’s numbers, about 20 GW of new capacity was added in the first half of this year, and solar accounts for 60 percent of it. Over a third of the solar additions occurred in just two states, Texas and Florida. There were two projects that went live that were rated at over 600 MW of capacity, one in Texas, the other in Nevada.

Next up is batteries: The US saw 4.2 additional gigawatts of battery capacity during this period, meaning over 20 percent of the total new capacity. (Batteries are treated as the equivalent of a generating source by the EIA since they can dispatch electricity to the grid on demand, even if they can’t do so continuously.) Texas and California alone accounted for over 60 percent of these additions; throw in Arizona and Nevada, and you’re at 93 percent of the installed capacity.

The clear pattern here is that batteries are going where the solar is, allowing the power generated during the peak of the day to be used to meet demand after the sun sets. This will help existing solar plants avoid curtailing power production during the lower-demand periods in the spring and fall. In turn, this will improve the economic case for installing additional solar in states where its production can already regularly exceed demand.

Wind power, by contrast, is running at a more sedate pace, with only 2.5 GW of new capacity during the first six months of 2024. And for likely the last time this decade, additional nuclear power was placed on the grid, at the fourth 1.1 GW reactor (and second recent build) at the Vogtle site in Georgia. The only other additions came from natural gas-powered facilities, but these totaled just 400 MW, or just 2 percent of the total of new capacity.

Wind, solar, and batteries are the key contributors to new capacity in 2024.

Enlarge / Wind, solar, and batteries are the key contributors to new capacity in 2024.

The EIA has also projected capacity additions out to the end of 2024 based on what’s in the works, and the overall shape of things doesn’t change much. However, the pace of installation goes up as developers rush to get their project operational within the current tax year. The EIA expects a bit over 60 GW of new capacity to be installed by the end of the year, with 37 GW of that coming in the form of solar power. Battery growth continues at a torrid pace, with 15 GW expected, or roughly a quarter of the total capacity additions for the year.

Wind will account for 7.1 GW of new capacity, and natural gas 2.6 GW. Throw in the contribution from nuclear, and 96 percent of the capacity additions of 2024 are expected to operate without any carbon emissions. Even if you choose to ignore the battery additions, the fraction of carbon-emitting capacity added remains extremely small, at only 6 percent.

Gradual shifts on the grid

Obviously, these numbers represent the peak production of these sources. Over a year, solar produces at about 25 percent of its rated capacity in the US, and wind at about 35 percent. The former number will likely decrease over time as solar becomes inexpensive enough to make economic sense in places that don’t receive as much sunshine. By contrast, wind’s capacity factor may increase as more offshore wind farms get completed. For natural gas, many of the newer plants are being designed to operate erratically so that they can provide power when renewables are under-producing.

A clearer sense of what’s happening comes from looking at the generating sources that are being retired. The US saw 5.1 GW of capacity drop off the grid in the first half of 2024, and aside from a 0.2 GW of “other,” all of it was fossil fuel-powered, including 2.1 GW of coal capacity and 2.7 GW of natural gas. The latter includes a large 1.4 GW natural gas plant in Massachusetts.

But total retirements are expected to be just 7.5 GWO this year—less than was retired in the first half of 2023. That’s likely because the US saw electricity use rise by 5 percent in the first half of 2025, based on numbers the EIA released on Friday (note that this link will take you to more recent data a month from now). It’s unclear how much of that was due to weather—a lot of the country saw heat that likely boosted demand for air conditioning—and how much could be accounted for by rising use in data centers and for the electrification of transit and appliances.

That data release includes details on where the US got its electricity during the first half of 2024. The changes aren’t dramatic compared to where they were when we looked at things last month. Still, what has changed over the past month is good news for renewables. In May, wind and solar production were up 8.4 percent compared to the same period the year before. By June, they were up by over 12 percent.

Given the EIA’s expectations for the rest of the year, the key question is likely to be whether the pace of new solar installations is going to be enough to offset the drop in production that will occur as the US shifts to the winter months.

US grid adds batteries at 10x the rate of natural gas in first half of 2024 Read More »

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US solar production soars by 25 percent in just one year

Energy, fossil fuels, nuclear power, renewable energy, Science, Sustainability / /

Solar sailing —

2024 is seeing the inevitable outcome of the building boom in solar farms.

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A single construction person set in the midst of a sea of solar panels.

With the plunging price of photovoltaics, the construction of solar plants has boomed in the US. Last year, for example, the US’s Energy Information Agency expected that over half of the new generating capacity would be solar, with a lot of it coming online at the very end of the year for tax reasons. Yesterday, the EIA released electricity generation numbers for the first five months of 2024, and that construction boom has seemingly made itself felt: generation by solar power has shot up by 25 percent compared to just one year earlier.

The EIA breaks down solar production according to the size of the plant. Large grid-scale facilities have their production tracked, giving the EIA hard numbers. For smaller installations, like rooftop solar on residential and commercial buildings, the agency has to estimate the amount produced, since the hardware often resides behind the metering equipment, so only shows up via lower-than-expected consumption.

In terms of utility-scale production, the first five months of 2024 saw it rise by 29 percent compared to the same period in the year prior. Small-scale solar was “only” up by 18 percent, with the combined number rising by 25.3 percent.

Most other generating sources were largely flat, year over year. This includes coal, nuclear, and hydroelectric, all of which changed by 2 percent or less. Wind was up by 4 percent, while natural gas rose by 5 percent. Because natural gas is the largest single source of energy on the grid, however, its 5 percent rise represents a lot of electrons—slightly more than the total increase in wind and solar.

US electricity sources for January through May of 2024. Note that the numbers do not add up to 100 percent due to the omission of minor contributors like geothermal and biomass.

Enlarge / US electricity sources for January through May of 2024. Note that the numbers do not add up to 100 percent due to the omission of minor contributors like geothermal and biomass.

John Timmer

Overall, energy use was up by about 4 percent compared to the same period in 2023. This could simply be a matter of changing weather conditions that require more heating or cooling. But there have been several trends that should increase electricity usage: the rise of bitcoin mining, the growth of data centers, and the electrification of appliances and transport. So far, that hasn’t shown up in the actual electricity usage in the US, which has stayed largely flat for decades. It could be possible that 2024 is the year when usage starts going up again.

More to come

It’s worth noting that this data all comes from before some of the most productive months of the year for solar power; overall, the EIA is predicting that solar production could rise by as much as 42 percent in 2024.

So, where does this leave the US’s efforts to decarbonize? If we combine nuclear, hydro, wind, and solar under the umbrella of carbon-free power sources, then these account for about 45 percent of US electricity production so far this year. Within that category, wind and solar now produce more than three times hydroelectric, and roughly the same amount as nuclear.

Wind and solar have also produced 1.3 times as much electricity as coal so far in 2024, with solar alone now producing about half as much as coal. That said, natural gas still produces twice as much electricity as wind and solar combined, indicating we still have a long way to go to decarbonize our grid.

When you look at the generating facilities that will be built over the next 12 months, it's difficult not to see a pattern.

Enlarge / When you look at the generating facilities that will be built over the next 12 months, it’s difficult not to see a pattern.

Still, we can expect solar’s productivity to climb even before the year is out. That’s in part because we don’t yet have numbers for June, the month that contains the longest day of the year. But it’s also because the construction boom shows no sign of stopping. As noted here, solar and wind deployments are expected to dwarf everything else over the coming year. The items in gray on the map primarily represent battery storage, which will allow us to make better use of those renewables, as well.

By contrast, facilities that are scheduled for retirement over the next year largely consist of coal and natural gas plants.

US solar production soars by 25 percent in just one year Read More »