Solar surpasses coal to become ERCOT’s third-largest power source in 2025

by the numbers

Solar represented 14 percent of energy supplied to the ERCOT electric grid in 2025. Photo via bp.com

Solar barely eclipsed coal to become the third biggest source of energy generated for the Electric Reliability Council of Texas (ERCOT) in 2025, according to new data.

In 2024, solar represented 10 percent of energy supplied to the ERCOT electric grid. Last year, that number climbed to 14 percent. During the same period, coal’s share remained at 13 percent.

From the largest to smallest share, here’s the breakdown of other ERCOT energy sources in 2025 compared with 2024:

Combined-cycle gas: 33 percent, down from 35 percent in 2024
Wind: 23 percent, down from 24 percent in 2024
Natural gas: 8 percent, down from 9 percent in 2024
Nuclear: 8 percent, unchanged from 2024
Other sources: 1 percent, unchanged from 2024

Combined, solar and wind accounted for 37 percent of ERCOT energy sources.

Looking ahead, solar promises to reign as the star of the ERCOT show:

An ERCOT report released in December 2024 said solar is on track to continue outpacing other energy sources in terms of growth of installed generating capacity, followed by battery energy storage.
In December, ERCOT reported that more than 11,100 megawatts of new generating capacity had been added to its grid since the previous winter. One megawatt of electricity serves about 250 homes in peak-demand periods. Battery energy storage made up 47 percent of the new capacity, with solar in second place at 40 percent.

The mix of ERCOT’s energy is critical to Texas’ growing need for electricity, as ERCOT manages about 90 percent of the electric load for the state, including the Houston metro area. Data centers, AI and population growth are driving heightened demand for electricity.

In the first nine months of 2025, Texas added a nation-leading 7.4 gigawatts of solar capacity, according to a report from data and analytics firm Wood Mackenzie and the Solar Energy Industries Association.

“Remarkable growth in Texas, Indiana, Utah and other states ... shows just how decisively the market is moving toward solar,” says Abigail Ross Hopper, president and CEO of the solar association.

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Time is of the essence in getting power plants online. Getty Images

Big Tech's soaring energy demands making coal-fired power plant sites attractive

Transforming Coal Power

Coal-fired power plants, long an increasingly money-losing proposition in the U.S., are becoming more valuable now that the suddenly strong demand for electricity to run Big Tech's cloud computing and artificial intelligence applications has set off a full-on sprint to find new energy sources.

President Donald Trump — who has pushed for U.S. “energy dominance” in the global market and suggested that coal can help meet surging power demand — is wielding his emergency authority to entice utilities to keep older coal-fired plants online and producing electricity.

While some utilities were already delaying the retirement of coal-fired plants, the scores of coal-fired plants that have been shut down the past couple years — or will be shut down in the next couple years — are the object of growing interest from tech companies, venture capitalists, states and others competing for electricity.

That’s because they have a very attractive quality: high-voltage lines connecting to the electricity grid that they aren’t using anymore and that a new power plant could use.

That ready-to-go connection could enable a new generation of power plants — gas, nuclear, wind, solar or even battery storage — to help meet the demand for new power sources more quickly.

For years, the bureaucratic nightmare around building new high-voltage power lines has ensnared efforts to get permits for such interconnections for new power plants, said John Jacobs, an energy policy analyst for the Washington, D.C.-based Bipartisan Policy Center.

“They are very interested in the potential here. Everyone sort of sees the writing on the wall for the need for transmission infrastructure, the need for clean firm power, the difficulty with siting projects and the value of reusing brownfield sites,” Jacobs said.

Rising power demand, dying coal plants

Coincidentally, the pace of retirements of the nation's aging coal-fired plants had been projected to accelerate at a time when electricity demand is rising for the first time in decades.

The Department of Energy, in a December report, said its strategy for meeting that demand includes re-using coal plants, which have been unable to compete with a flood of cheap natural gas while being burdened with tougher pollution regulations aimed at its comparatively heavy emissions of planet-warming greenhouse gases.

There are federal incentives, as well — such as tax credits and loan guarantees — that encourage the redevelopment of retired coal-fired plants into new energy sources.

Todd Snitchler, president and CEO of the Electric Power Supply Association, which represents independent power plant owners, said he expected Trump's executive orders will mean some coal-fired plants run longer than they would have — but that they are still destined for retirement.

Surging demand means power plants are needed, fast

Time is of the essence in getting power plants online.

Data center developers are reporting a yearlong wait in some areas to connect to the regional electricity grid. Rights-of-way approvals to build power lines can also be difficult to secure, given objections by neighbors who may not want to live near them.

Stephen DeFrank, chairman of the Pennsylvania Public Utility Commission, said he believes rising energy demand has made retiring coal-fired plants far more valuable.

That's especially true now that the operator of the congested mid-Atlantic power grid has re-configured its plans to favor sites like retired coal-fired plants as a shortcut to meet demand, DeFrank said.

“That’s going to make these properties more valuable because now, as long as I’m shovel ready, these power plants have that connection already established, I can go in and convert it to whatever," DeFrank said.

Gas, solar and more at coal power sites

In Pennsylvania, the vast majority of conversions is likely to be natural gas because Pennsylvania sits atop the prolific Marcellus Shale reservoir, DeFrank said.

In states across the South, utilities are replacing retiring or retired coal units with gas. That includes a plant owned by the Tennessee Valley Authority; a Duke Energy project in North Carolina; and a Georgia Power plant.

The high-voltage lines at retired coal plants on the Atlantic Coast in New Jersey and Massachusetts were used to connect offshore wind turbines to electricity grids.

In Alabama, the site of a coal-fired plant, Plant Gorgas, shuttered in 2019, will become home to Alabama Power’s first utility-scale battery energy storage plant.

Texas-based Vistra, meanwhile, is in the process of installing solar panels and energy storage plants at a fleet of retired and still-operating coal-fired plants it owns in Illinois, thanks in part to state subsidies approved there in 2021.

Nuclear might be coming

Nuclear is also getting a hard look.

In Arizona, lawmakers are advancing legislation to make it easier for three utilities there — Arizona Public Service, Salt River Project and Tucson Electric Power — to put advanced nuclear reactors on the sites of retiring coal-fired plants.

At the behest of Indiana's governor, Purdue University studied how the state could attract a new nuclear power industry. In its November report, it estimated that reusing a coal-fired plant site for a new nuclear power plant could reduce project costs by between 7% and 26%.

The Bipartisan Policy Center, in a 2023 study before electricity demand began spiking, estimated that nuclear plants could cut costs from 15% to 35% by building at a retiring coal plant site, compared to building at a new site.

Even building next to the coal plant could cut costs by 10% by utilizing transmission assets, roads and buildings while avoiding some permitting hurdles, the center said.

That interconnection was a major driver for Terrapower when it chose to start construction in Wyoming on a next-generation nuclear power plant next to PacifiCorp’s coal-fired Naughton Power Plant.

Jobs, towns left behind by coal

Kathryn Huff, a former U.S. assistant secretary for nuclear energy who is now an associate professor at the University of Illinois Urbana-Champaign, said the department analyzed how many sites might be suitable to advanced nuclear reactor plants.

A compelling factor is the workers from coal plants who can be trained for work at a nuclear plant, Huff said. Those include electricians, welders and steam turbine maintenance technicians.

In Homer City, the dread of losing its coal-fired plant — it shut down in 2023 after operating for 54 years — existed for years in the hills of western Pennsylvania’s coal country.

“It’s been a rough 20 years here for our area, maybe even longer than that, with the closing of the mines, and this was the final nail, with the closing of the power plant,” said Rob Nymick, Homer City's manager. “It was like, ‘Oh my god, what do we do?’”

That is changing.

The plant's owners in recent weeks demolished the smoke stacks and cooling towers at the Homer City Generating State and announced a $10 billion plan for a natural gas-powered data center campus.

It would be the nation’s third-largest power generator and that has sown some optimism locally.

“Maybe we will get some families moving in, it would help the school district with their enrollment, it would help us with our population,” Nymick said. “We’re a dying town and hopefully maybe we can get a restaurant or two to open up and start thriving again. We’re hoping.”

Energy sources are often categorized as renewable or not, but perhaps a more accurate classification focuses on the type of reaction that converts energy into useful matter. Photo by simpson33/Getty Images

How is energy produced?

ENERGY 101

Many think of the Energy Industry as a dichotomy–old vs. new, renewable vs. nonrenewable, good vs. bad. But like most things, energy comes from an array of sources, and each kind has its own unique benefits and challenges. Understanding the multi-faceted identity of currently available energy sources creates an environment in which new ideas for cleaner and more sustainable energy sourcing can proliferate.

At a high level, energy can be broadly categorized by the process of extracting and converting it into a useful form.

Energy Produced from Chemical Reaction

Energy derived from coal, crude oil, natural gas, and biomass is primarily produced as a result of bonds breaking during a chemical reaction. When heated, burned, or fermented, organic matter releases energy, which is converted into mechanical or electrical energy.

These sources can be stored, distributed, and shared relatively easily and do not have to be converted immediately for power consumption. However, the resulting chemical reaction produces environmentally harmful waste products.

Though the processes to extract these organic sources of energy have been refined for many years to achieve reliable and cheap energy, they can be risky and are perceived as invasive to mother nature.

According to the 2022 bp Statistical Review of World Energy, approximately 50% of the world’s energy consumption comes from petroleum and natural gas; another 25% from coal. Though there was a small decline in demand for oil from 2019 to 2021, the overall demand for fossil fuels remained unchanged during the same time frame, mostly due to the increase in natural gas and coal consumption.

Energy Produced from Mechanical Reaction

Energy captured from the earth’s heat or the movement of wind and water results from the mechanical processes enabled by the turning of turbines in source-rich environments. These turbines spin to produce electricity inside a generator.

Solar energy does not require the use of a generator but produces electricity due to the release of electrons from the semiconducting materials found on a solar panel. The electricity produced by geothermal, wind, solar, and hydropower is then converted from direct current to alternating current electricity.

Electricity is most useful for immediate consumption, as storage requires the use of batteries–a process that turns electrical energy into chemical energy that can then be accessed in much the same way that coal, crude oil, natural gas, and biomass produce energy.

Energy Produced from a Combination of Reactions

Hydrogen energy comes from a unique blend of both electrical and chemical energy processes. Despite hydrogen being the most abundant element on earth, it is rarely found on its own, requiring a two-step process to extract and convert energy into a usable form. Hydrogen is primarily produced as a by-product of fossil fuels, with its own set of emissions challenges related to separating the hydrogen from the hydrocarbons.

Many use electrolysis to separate hydrogen from other elements before performing a chemical reaction to create electrical energy inside of a contained fuel cell. The electrolysis process is certainly a more environmentally-friendly solution, but there are still great risks with hydrogen energy–it is highly flammable, and its general energy output is less than that of other electricity-generating methods.

Energy Produced from Nuclear Reaction

Finally, energy originating from the splitting of an atom’s nucleus, mostly through nuclear fission, is yet another way to produce energy. A large volume of heat is released when an atom is bombarded by neutrons in a nuclear power plant, which is then converted to electrical energy.

This process also produces a particularly sensitive by-product known as radiation, and with it, radioactive waste. The proper handling of radiation and radioactive waste is of utmost concern, as its effects can be incredibly damaging to the environment surrounding a nuclear power plant.

Nuclear fission produces minimal carbon, so nuclear energy is oft considered environmentally safe–as long as strict protocols are followed to ensure proper storage and disposal of radiation and radioactive waste.

Nuclear to Mechanical to Chemical?

Interestingly enough, the Earth’s heat comes from the decay of radioactive materials in the Earth’s core, loosely linking nuclear power production back to geothermal energy production.

It’s also clear the conversion of energy into electricity is the cleanest option for the environment, yet adequate infrastructure remains limited in supply and accessibility. If not consumed immediately as electricity, energy is thus converted into a chemical form for the convenience of storage and distribution it provides.

Perhaps the expertise and talent of Houstonians serving the flourishing academic and industrial sectors of energy development will soon resolve many of our current energy challenges by exploring further the circular dynamic of the energy environment. Be sure to check out our Events Page to find the networking event that best serves your interest in the Energy Transition.

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Lindsey Ferrell is a contributing writer to EnergyCapitalHTX and founder of Guerrella & Co.

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Spring-based private equity firm acquires West Texas wind farm

power deal

Spring-based private equity firm Arroyo Investors has teamed up with ONCEnergy, a Portland, Oregon-based developer of clean energy projects, to buy a 60-megawatt wind farm southeast of Amarillo.

Skyline Renewables, which acquired the site, known as the Whirlwind Energy Center, in 2018, was the seller. The purchase price wasn’t disclosed.

Whirlwind Energy Center, located in Floyd County, West Texas, comprises 26 utility-scale wind turbines. The wind farm, built in 2007, supplies power to Austin Energy.

“The acquisition reflects our focus on value-driven investments with strong counterparties, a solid operating track record, and clear relevance to markets with growing capacity needs,” Brandon Wax, a partner at Arroyo, said in a press release. “Partnering with ONCEnergy allows us to leverage deep operational expertise while expanding our investment footprint in the market.”

Arroyo focuses on energy infrastructure investments in the Americas. Its portfolio includes Spring-based Seaside LNG, which produces liquefied natural gas and LNG transportation services.

Last year, Arroyo closed an investment fund with more than $1 billion in total equity commitments.

Since its launch in 2003, Arroyo has “remained committed to investing in high-quality assets, creating value and positioning assets for exit within our expected hold period,” founding partner Chuck Jordan said in 2022.

$524M Texas Hill Country solar project powered by Hyundai kicks off

powering up

Corporate partners—including Hyundai Engineering & Construction, which maintains a Houston office—kicked off a $524 million solar power project in the Texas Hill Country on Jan. 27.

The 350-megawatt, utility-scale Lucy Solar Project is scheduled to go online in mid-2027 and represents one of the largest South Korean-led investments in U.S. renewable energy.

The solar farm, located on nearly 2,900 acres of ranchland in Concho County, will generate 926 gigawatt-hours of solar power each year. That’s enough solar power to supply electricity to roughly 65,000 homes in Texas.

Power to be produced by the hundreds of thousands of the project’s solar panels has already been sold through long-term deals to buyers such as Starbucks, Workday and Plano-based Toyota Motor North America.

The project is Hyundai Engineering & Construction’s largest solar power initiative outside Asia.

“The project is significant because it’s the first time Hyundai E&C has moved beyond its traditional focus on overseas government contracts to solidify its position in the global project financing market,” the company, which is supplying solar modules for the project, says on its website.

Aside from Hyundai Engineering & Construction, a subsidiary of automaker Hyundai, Korean and U.S. partners in the solar project include Korea Midland Power, the Korea Overseas Infrastructure & Urban Development Corp., solar panel manufacturer Topsun, investment firm EIP Asset Management, Primoris Renewable Energy and High Road Energy Marketing.

Primoris Renewable Energy is an Aurora, Colorado-based subsidiary of Dallas-based Primoris Services Corp. Another subsidiary, Primoris Energy Services, is based in Houston.

High Road is based in the Austin suburb of West Lake Hills.

“The Lucy Solar Project shows how international collaboration can deliver local economic development and clean power for Texas communities and businesses,” says a press release from the project’s partners.

Elon Musk vows to put data centers in space and run them on solar power

Outer Space

Elon Musk vowed this week to upend another industry just as he did with cars and rockets — and once again he's taking on long odds.

The world's richest man said he wants to put as many as a million satellites into orbit to form vast, solar-powered data centers in space — a move to allow expanded use of artificial intelligence and chatbots without triggering blackouts and sending utility bills soaring.

To finance that effort, Musk combined SpaceX with his AI business on Monday, February 2, and plans a big initial public offering of the combined company.

“Space-based AI is obviously the only way to scale,” Musk wrote on SpaceX’s website, adding about his solar ambitions, “It’s always sunny in space!”

But scientists and industry experts say even Musk — who outsmarted Detroit to turn Tesla into the world’s most valuable automaker — faces formidable technical, financial and environmental obstacles.

Feeling the heat

Capturing the sun’s energy from space to run chatbots and other AI tools would ease pressure on power grids and cut demand for sprawling computing warehouses that are consuming farms and forests and vast amounts of water to cool.

But space presents its own set of problems.

Data centers generate enormous heat. Space seems to offer a solution because it is cold. But it is also a vacuum, trapping heat inside objects in the same way that a Thermos keeps coffee hot using double walls with no air between them.

“An uncooled computer chip in space would overheat and melt much faster than one on Earth,” said Josep Jornet, a computer and electrical engineering professor at Northeastern University.

One fix is to build giant radiator panels that glow in infrared light to push the heat “out into the dark void,” says Jornet, noting that the technology has worked on a small scale, including on the International Space Station. But for Musk's data centers, he says, it would require an array of “massive, fragile structures that have never been built before.”

Floating debris

Then there is space junk.

A single malfunctioning satellite breaking down or losing orbit could trigger a cascade of collisions, potentially disrupting emergency communications, weather forecasting and other services.

Musk noted in a recent regulatory filing that he has had only one “low-velocity debris generating event" in seven years running Starlink, his satellite communications network. Starlink has operated about 10,000 satellites — but that's a fraction of the million or so he now plans to put in space.

“We could reach a tipping point where the chance of collision is going to be too great," said University at Buffalo's John Crassidis, a former NASA engineer. “And these objects are going fast -- 17,500 miles per hour. There could be very violent collisions."

No repair crews

Even without collisions, satellites fail, chips degrade, parts break.

Special GPU graphics chips used by AI companies, for instance, can become damaged and need to be replaced.

“On Earth, what you would do is send someone down to the data center," said Baiju Bhatt, CEO of Aetherflux, a space-based solar energy company. "You replace the server, you replace the GPU, you’d do some surgery on that thing and you’d slide it back in.”

But no such repair crew exists in orbit, and those GPUs in space could get damaged due to their exposure to high-energy particles from the sun.

Bhatt says one workaround is to overprovision the satellite with extra chips to replace the ones that fail. But that’s an expensive proposition given they are likely to cost tens of thousands of dollars each, and current Starlink satellites only have a lifespan of about five years.

Competition — and leverage

Musk is not alone trying to solve these problems.

A company in Redmond, Washington, called Starcloud, launched a satellite in November carrying a single Nvidia-made AI computer chip to test out how it would fare in space. Google is exploring orbital data centers in a venture it calls Project Suncatcher. And Jeff Bezos’ Blue Origin announced plans in January for a constellation of more than 5,000 satellites to start launching late next year, though its focus has been more on communications than AI.

Still, Musk has an edge: He's got rockets.

Starcloud had to use one of his Falcon rockets to put its chip in space last year. Aetherflux plans to send a set of chips it calls a Galactic Brain to space on a SpaceX rocket later this year. And Google may also need to turn to Musk to get its first two planned prototype satellites off the ground by early next year.

Pierre Lionnet, a research director at the trade association Eurospace, says Musk routinely charges rivals far more than he charges himself —- as much as $20,000 per kilo of payload versus $2,000 internally.

He said Musk’s announcements this week signal that he plans to use that advantage to win this new space race.

“When he says we are going to put these data centers in space, it’s a way of telling the others we will keep these low launch costs for myself,” said Lionnet. “It’s a kind of powerplay.”

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