renewable energy

A fluid can store solar energy and then release it as heat months later

chemistry, green, heating, materials science, renewable energy, Science, solar / Paul Patrick / February 16, 2026

Sunlight can cause a molecule to change structure, and then release heat later.

The system works a bit like existing solar water heaters, but with chemical heat storage. Credit: Kypros

Heating accounts for nearly half of the global energy demand, and two-thirds of that is met by burning fossil fuels like natural gas, oil, and coal. Solar energy is a possible alternative, but while we have become reasonably good at storing solar electricity in lithium-ion batteries, we’re not nearly as good at storing heat.

To store heat for days, weeks, or months, you need to trap the energy in the bonds of a molecule that can later release heat on demand. The approach to this particular chemistry problem is called molecular solar thermal (MOST) energy storage. While it has been the next big thing for decades, it never really took off.

In a recent Science paper, a team of researchers from the University of California, Santa Barbara, and UCLA demonstrate a breakthrough that might finally make MOST energy storage effective.

The DNA connection

In the past, MOST energy storage solutions have been plagued by lackluster performance. The molecules either didn’t store enough energy, degraded too quickly, or required toxic solvents that made them impractical. To find a way around these issues, the team led by Han P. Nguyen, a chemist at the University of California, Santa Barbara, drew inspiration from the genetic damage caused by sunburn. The idea was to store energy using a reaction similar to the one that allows UV light to damage DNA.

When you stay out on the beach too long, high-energy ultraviolet light can cause adjacent bases in the DNA (thymine, the T in the genetic code) to link together. This forms a structure known as a (6-4) lesion. When that lesion is exposed to even more UV light, it twists into an even stranger shape called a “Dewar” isomer. In biology, this is rather bad news, as Dewar isomers cause kinks in the DNA’s double-helix spiral that disrupt copying the DNA and can lead to mutations or cancer.

To counter this effect, evolution shaped a specific enzyme called photolyase to hunt (6-4) lesions down and snap them back into their safe, stable forms.

The researchers realized that the Dewar isomer is essentially a molecular battery. This snap-back effect was exactly what Nguyen’s team was looking for, since it releases a lot of heat.

Rechargeable fuel

Molecular batteries, in principle, are extremely good at storing energy. Heating oil, arguably the most popular molecular battery we use for heating, is essentially ancient solar energy stored in chemical bonds. Its energy density stands at around 40 Megajoules per kilo. To put that in perspective, Li-ion batteries usually pack less than one MJ/kg. One of the problems with heating oil, though, is that it is single-use only—it gets burnt when you use it. What Nguyen and her colleagues aimed to achieve with their DNA-inspired substance is essentially a reusable fuel.

To do that, researchers synthesized a derivative of 2-pyrimidone, a chemical cousin of the thymine found in DNA. They engineered this molecule to reliably fold into a Dewar isomer under sunlight and then unfold on command. The result was a rechargeable fuel that could absorb the energy when exposed to sunlight, release it when needed, and return to a “relaxed” state where it’s ready to be charged up again.

Previous attempts at MOST systems have struggled to compete with Li-ion batteries. Norbornadiene, one of the best-studied candidates, tops out at around 0.97 MJ/kg. Another contender, azaborinine, manages only 0.65 MJ/kg. They may be scientifically interesting, but they are not going to heat your house.

Nguyen’s pyrimidone-based system blew those numbers out of the water. The researchers achieved an energy storage density of 1.65 MJ/kg—nearly double the capacity of Li-ion batteries and substantially higher than any previous MOST material.

Double rings

The reason for this jump in performance was what the team called compounded strain.

When the pyrimidone molecule absorbs light, it doesn’t just fold; it twists into a fused, bicyclic structure containing two different four-membered rings: 1,2-dihydroazete and diazetidine. Four-membered rings are under immense structural tension. By fusing them together, the researchers created a molecule that is desperate to snap back into its relaxed state.

Achieving high energy density on paper is one thing. Making it work in the real world is another. A major failing of previous MOST systems is that they are solids that need to be dissolved in solvents like toluene or acetonitrile to work. Solvents are the enemy of energy density—by diluting your fuel to 10 percent concentration, for example, you effectively cut your energy density by 90 percent. Any solvent used means less fuel.

Nguyen’s team tackled this by designing a version of their molecule that is a liquid at room temperature, so it doesn’t need a solvent. This simplified operations considerably, as the liquid fuel could be pumped through a solar collector to charge it up and store it in a tank.

Unlike many organic molecules that hate water, Nguyen’s system is compatible with aqueous environments. This means if a pipe leaks, you aren’t spewing toxic fluids like toluene around your house. The researchers even demonstrated that the molecule could work in water and that its energy release was intense enough to boil it.

The MOST-based heating system, the team says in their paper, would circulate this rechargeable fuel through panels on the roof to capture the sun’s light and then store it in the basement tank. The fuel from this tank would later be pumped to a reaction chamber with an acid catalyst that triggers the energy release. Then, through a heat exchanger, this energy would heat up the water in the standard central heating system.

But there’s a catch.

Looking for the leak

The first hurdle is the spectrum of light that puts energy in the Nguyen’s fuel. The Sun bathes us in a broad spectrum of light, from infrared to ultraviolet. Ideally, a solar collector should use as much of this as possible, but the pyrimidone molecules only absorb light in the UV-A and UV-B range, around 300-310 nm. That represents about five percent of the total solar spectrum. The vast majority of the Sun’s energy, the visible light and the infrared, passes right through Nguyen’s molecules without charging them.

The second problem is quantum yield. This is a fancy way of asking, “For every 100 photons that hit the molecule, how many actually make it switch to the Dewar isomer state?” For these pyrimidones, the answer is a rather underwhelming number, in the single digits. Low quantum yield means the fluid needs a longer exposure to sunlight to get a full charge.

The researchers hypothesize that the molecule has a fast leak, meaning a non-radiative decay path where the excited molecule shakes off the energy as heat immediately instead of twisting into the storage form. Plugging that leak is the next big challenge for the team.

Finally, the team in their experiments used an acid catalyst that was mixed directly into the storage material. The team admits that in a future closed-loop device, this would require a neutralization step—a reaction that eliminates the acidity after the heat is released. Unless the reaction products can be purified away, this will reduce the energy density of the system.

Still, despite the efficiency issues, the stability of the Nguyen’s system looks promising.

The MOST storage?

One of the biggest fears with chemical storage is thermal reversion—the fuel spontaneously discharges because it got a little too warm in the storage tank. But the Dewar isomers of the pyrimidones are incredibly stable. The researchers calculated a half-life of up to 481 days at room temperature for some derivatives. This means the fuel could be charged in the heat of July, and it would remain fully charged when you need to heat your home in January. The degradation figures also look decent for a MOST energy storage. The team ran the system through 20 charge-discharge cycles with negligible decay.

The problem with separating the acid from the fuel could be solved in a practical system by switching to a different catalyst. The scientists suggest in the paper that in this hypothetical setup, the fuel would flow through an acid-functionalized solid surface to release heat, thus eliminating the need for neutralization afterwards.

Still, we’re rather far away using MOST systems for heating actual homes. To get there, we’re going to need molecules that absorb far more of the light spectrum and convert to the activated state with a higher efficiency. We’re just not there yet.

Science, 2026. DOI: 10.1126/science.aec6413

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

A fluid can store solar energy and then release it as heat months later Read More »

Court orders restart of all US offshore wind construction

department of the interior, green, injunction, lawsuit, offshore wind, Policy, renewable energy, Science, trump administration, wind power / Kris Guyer / February 2, 2026

Based on reporting elsewhere, some of the judges viewed the classified report that was used to justify the order to halt construction, but they didn’t find it persuasive. In one case, the judge noted that the government wasn’t acting as if the security risks were real. The threat supposedly comes from the operation of the wind turbines, but the Department of the Interior’s order blocked construction while allowing any completed hardware to operate.

“If the government’s concern is the operation of these facilities, allowing the ongoing operation of the 44 turbines while prohibiting the repair of the existing turbines and the completion of the 18 additional turbines is irrational,” Judge Brian E. Murphy said. That once again raises the possibility that the order halting construction will ultimately be held to be arbitrary and capricious.

For now, however, the courts are largely offering the wind projects relief because the ruling was issued without any warning or communication from the government and would clearly inflict substantial harm on the companies building them. The injunction blocks the government’s hold on construction until a final ruling is issued. The government can still appeal the decision before that point, but the consistency among these rulings suggests it will likely fail.

Several of these projects are near completion and are likely to be done before any government appeal can be heard.

Court orders restart of all US offshore wind construction Read More »

US blocks all offshore wind construction, says reason is classified

Department of Defense, department of Interior, green, offshore wind, Policy, renewable energy, Science, Trump, Wind / Rejus Almole / December 22, 2025

On Monday, the US Department of the Interior announced that it was pausing the leases on all five offshore wind sites currently under construction in the US. The move comes despite the fact that these projects already have installed significant hardware in the water and on land; one of them is nearly complete. In what appears to be an attempt to avoid legal scrutiny, the Interior is blaming the decisions on a classified report from the Department of Defense.

The second Trump administration announced its animosity toward offshore wind power literally on day one, issuing an executive order on inauguration day that called for a temporary halt to issuing permits for new projects pending a re-evaluation. Earlier this month, however, a judge vacated that executive order, noting that the government has shown no indication that it was even attempting to start the re-evaluation it said was needed.

But a number of projects have gone through the entire permitting process, and construction has started. Before today, the administration had attempted to stop these in an erratic, halting manner. Empire Wind, an 800 MW farm being built off New York, was stopped by the Department of the Interior, which alleged that it had been rushed through permitting. That hold was lifted following lobbying and negotiations by New York and the project developer Orsted, and the Department of the Interior never revealed why it changed its mind. When the Interior Department blocked a second Orsted project, Revolution Wind offshore of southern New England, the company took the government to court and won a ruling that let it continue construction.

US blocks all offshore wind construction, says reason is classified Read More »

Judge lets construction on an offshore wind farm resume

injunction, lawsuit, offshore wind, renewable energy, Science, trump administration, wind power / Rejus Almole / September 23, 2025

That did not, however, stop the administration from trying again, this time targeting a development called Revolution Wind, located a bit further north along the Atlantic coast. This time, however, the developer quickly sued, leading to Monday’s ruling. According to Reuters, after a two-hour court hearing at the District Court of DC, Judge Royce Lamberth termed the administration’s actions “the height of arbitrary and capricious” and issued a preliminary injunction against the hold on Revolution Wind’s construction. As a result, Orsted can restart work immediately.

The decision provides a strong indication of how Lamberth is likely to rule if the government pursues a full trial on the case. And while the Trump administration could appeal, it’s unlikely to see this injunction lifted unless it takes the case all the way to the Supreme Court. Given that Revolution Wind was already 80 percent complete, the case may become moot before it gets that far.

Judge lets construction on an offshore wind farm resume Read More »

AI in Wyoming may soon use more electricity than state’s human residents

AI, ai data center, AI development tools, AI infrastructure, AI policy, Biz & IT, Cheyenne, Chris Lehane, Crusoe, datacenters, Energy, machine learning, Mark Gordon, Meta, microsoft, natural gas, openai, oracle, Patrick Collins, Policy, renewable energy, Tallgrass, wyoming / Tim Belzer / July 30, 2025

Wyoming’s data center boom

Cheyenne is no stranger to data centers, having attracted facilities from Microsoft and Meta since 2012 due to its cool climate and energy access. However, the new project pushes the state into uncharted territory. While Wyoming is the nation’s third-biggest net energy supplier, producing 12 times more total energy than it consumes (dominated by fossil fuels), its electricity supply is finite.

While Tallgrass and Crusoe have announced the partnership, they haven’t revealed who will ultimately use all this computing power—leading to speculation about potential tenants.

A potential connection to OpenAI’s Stargate AI infrastructure project, announced in January, remains a subject of speculation. When asked by The Associated Press if the Cheyenne project was part of this effort, Crusoe spokesperson Andrew Schmitt was noncommittal. “We are not at a stage that we are ready to announce our tenant there,” Schmitt said. “I can’t confirm or deny that it’s going to be one of the Stargate.”

OpenAI recently activated the first phase of a Crusoe-built data center complex in Abilene, Texas, in partnership with Oracle. Chris Lehane, OpenAI’s chief global affairs officer, told The Associated Press last week that the Texas facility generates “roughly and depending how you count, about a gigawatt of energy” and represents “the largest data center—we think of it as a campus—in the world.”

OpenAI has committed to developing an additional 4.5 gigawatts of data center capacity through an agreement with Oracle. “We’re now in a position where we have, in a really concrete way, identified over five gigawatts of energy that we’re going to be able to build around,” Lehane told the AP. The company has not disclosed locations for these expansions, and Wyoming was not among the 16 states where OpenAI said it was searching for data center sites earlier this year.

AI in Wyoming may soon use more electricity than state’s human residents Read More »

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

Energy, energy policy, renewable energy, Science, Sustainability / Kris Guyer / February 6, 2025

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 »

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

carbon emissions, coal, Energy, hydro, natural gas, nuclear, renewable energy, Science, solar, Wind / Kris Guyer / January 27, 2025

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 »

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

carbon emissions, electric grid, Energy, EPA, Policy, renewable energy, Science, Sustainability / Tim Belzer / January 9, 2025

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).

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 »

Desalination system adjusts itself to work with renewable power

chemistry, electrochemistry, materials science desalination, renewable energy, Science, Sustainability / Mike M. / October 18, 2024

Instead of needing constant power, new system adjusts to use whatever is available.

Image of a small tanker truck parked next to a few shipping container shaped structures, which are connected by pipes to storage tanks.

Mobile desalination plants might be easier to operate with renewable power. Credit: Ismail BELLAOUALI

Fresh water we can use for drinking or agriculture is only about 3 percent of the global water supply, and nearly 70 percent of that is trapped in glaciers and ice caps. So far, that was enough to keep us going, but severe draughts have left places like Jordan, Egypt, sub-Saharan Africa, Spain, and California with limited access to potable water.

One possible solution is to tap into the remaining 97 percent of the water we have on Earth. The problem is that this water is saline, and we need to get the salt out of it to make it drinkable. Desalination is also an energy-expensive process. But MIT researchers led by Jonathan Bessette might have found an answer to that. They built an efficient, self-regulating water desalination system that runs on solar power alone with no need for batteries or a connection to the grid.

Probing the groundwaters

Oceans are the most obvious source of water for desalination. But they are a good option only for a small portion of people who live in coastal areas. Most of the global population—more or less 60 percent—lives farther than 100 kilometers from the coast, which makes using desalinated ocean water infeasible. So, Bessette and his team focused on groundwater instead.

“In terms of global demand, about 50 percent of low- to middle-income countries rely on groundwater,” Bessette says. This groundwater is trapped in underground reservoirs, abundant, and, in most places, present at depths below 300 meters. It comes mostly from the rain that penetrates the ground and fills empty spaces left by fractured rock formations. Sadly, as the rainwater seeps down it also picks up salts from the soil on its way. As a result, in New Mexico, for example, around 75 percent of groundwater is brackish, meaning less salty than seawater, but still too salty to drink.

Getting rid of the salt

We already have the ability to get the salt back out. “There are two broad categories within desalination technologies. The first is thermal and the other is based on using membranes,” Bessette explains.

Thermal desalination is something we figured out ages ago. You just boil the water and condense the steam, which leaves the salt behind. Boiling, however, needs lots of energy. Bringing 1 liter of room temperature water to 100° Celsius costs around 330 kilojoules of energy, assuming there’s no heat lost in the process. If you want a sense of how much energy that is, stop using your electric kettle for a month and see how your bill shrinks.

“So, around 100 years ago we developed reverse osmosis and electrodialysis, which are two membrane-based desalination technologies. This way, we reduced the power consumption by a factor of 10,” Bessette claims.

Reverse osmosis is a pressure-driven process; you push the water through a membrane that works like a very fine sieve that lets the molecules of water pass but stops other things like salts. Technologically advanced implementations of this idea are widely used at industrial facilities such as the Sydney Desalination Plant in Australia. Reverse osmosis today is the go-to technology when you want to desalinate water at scale. But it has its downsides.

“The issue is reverse osmosis requires a lot of pretreatment. We have to treat the water down to a pretty good quality, making sure the physical, chemical, or biological foul doesn’t end up on the membrane before we do the desalination process,” says Bessette. Another thing is that reverse osmosis relies on pressure, so it requires a steady supply of power to maintain this pressure, which is difficult to achieve in places where the grid is not reliable. Sensitivity to power fluctuations also makes it challenging to use with renewable energy sources like wind or solar. This is why to make their system work on solar energy alone, Bessette’s team went for electrodialysis.

Synching with the Sun

“Unlike reverse osmosis, electrodialysis is an electrically driven process,” Bessette says. The membranes are arranged in such a way that the water is not pushed through them but flows along them. On both sides of those membranes are positive and negative electrodes that create an electric field, which draws salt ions through the membranes and out of the water.

Off-grid desalination systems based on electrodialysis operate at constant power levels like toasters or other appliances, which means they require batteries to even out renewable energy’s fluctuations. Using batteries, in most cases, made them too expensive for the low-income communities that need them the most. Bessette and his colleagues solved that by designing a clever control system.

The two most important parameters in electrodialysis desalination are the flow rate of the water and the power you apply to the electrodes. To make the process efficient, you need to match those two. The advantage of electrodialysis is that it can operate at different power levels. When you have more available power, you can just pump more water through the system. When you have less power, you can slow the system down by reducing the water flow rate. You’ll produce less freshwater, but you won’t break anything this way.

Bessette’s team simplified the control down to two feedback loops. The first outer loop was tracking the power coming from the solar panels. On a sunny day, when the panels generated plenty of power, it fed more water into the system; when there was less power, it fed less water. The second inner loop tracked flow rate. When the flow rate was high, it applied more power to the electrodes; when it was low, it applied less power. The trick was to apply maximum available power while avoiding splitting the water into hydrogen and oxygen.

Once Bessette and his colleagues figured out the control system, they built a prototype desalination device. And it worked, with very little supervision, for half a year.

Water production at scale

Bessette’s prototype system, complete with solar panels, pumps, electronics, and an electrodialysis stack with all the electrodes and membranes, was compact enough to fit in a trailer. They took this trailer to the Brackish Groundwater National Research Facility in Alamogordo, New Mexico, and ran it for six months. On average, it desalinated around 5,000 liters of water per day—enough for a community of roughly 2,000 people.

“The nice thing with our technology is it is more of a control method. The concept can be scaled anywhere from this small community treatment system all the way to large-scale plants,” Bessette says. He said his team is now busy building an equivalent of a single water treatment train, a complete water desalination unit designed for big municipal water supplies. “Multiple such [systems] are implemented in such plants to increase the scale of water desalination process,” Bessette says. But he also thinks about small-scale solutions that can be fitted on a pickup truck and deployed rapidly in crisis scenarios like natural disasters.

“We’re also working on building a company. Me, two other staff engineers, and our professor. We’re really hoping to bring this technology to market and see that it reaches a lot of people. Our aim is to provide clean drinking water to folks in remote regions around the world,” Bessette says.

Nature Water, 2024. DOI: 10.1038/s44221-024-00314-6

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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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 / Rejus Almole / September 30, 2024

Into the black —

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

John Timmer – Sep 30, 2024 6: 22 pm UTC

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.

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).

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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 / Kris Guyer / August 26, 2024

In transition —

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

John Timmer – Aug 26, 2024 5: 41 pm UTC

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.

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.

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US solar production soars by 25 percent in just one year

Energy, fossil fuels, nuclear power, renewable energy, Science, Sustainability / Rejus Almole / July 25, 2024

Solar sailing —

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

John Timmer – Jul 25, 2024 7: 44 pm UTC

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.

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.

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