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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Houston expert discusses the clean energy founder's paradox

Guest Column

Everyone tells you to move fast and break things. In clean energy, moving fast without structural integrity means breaking the only planet we’ve got. This is the founder's paradox: you are building a company in an industry where the stakes are existential, the timelines are glacial, and the capital requires patience.

The myth of the lone genius in a garage doesn’t really apply here. Clean energy startups aren’t just fighting competitors. They are fighting physics, policy, and decades of existing infrastructure. This isn’t an app. You’re building something physical that has to work in the real world. It has to be cheaper, more reliable, and clearly better than fossil fuels. Being “green” alone isn’t enough. Scale is what matters.

Your biggest risks aren’t competitors. They’re interconnection delays, permitting timelines, supply chain fragility, and whether your first customer is willing to underwrite something that hasn’t been done before.

That reality creates a brutal filter. Successful founders in this space need deep technical knowledge and the ability to execute. You need to understand engineering, navigate regulation, and think in terms of markets and risk. You’re not just selling a product. You’re selling a future where your solution becomes the obvious choice. That means connecting short-term financial returns with long-term system change.

The capital is there, but it’s smarter and more demanding. Investors today have PhDs in electrochemistry and grid dynamics. They’ve been burned by promises of miracle materials that never left the lab. They don't fund visions; they fund pathways to impact that can scale and make financial sense. Your roadmap must show not just a brilliant invention, but a clear, believable plan to drive costs down over time.

Capital in this sector isn’t impressed by ambition alone. It wants evidence that risk is being retired in the right order — even if that means slower growth early.

Here’s the upside. The difficulty of clean energy is also its strength. If you succeed, your advantage isn’t just in software or branding. It’s in hardware, supply chains, approvals, and years of hard work that others can’t easily copy. Your real competitors aren’t other startups. They’re inertia and the existing system. Winning here isn’t zero-sum. When one solution scales, it helps the entire market grow.

So, to the founder in the lab, or running field tests at a remote site: your pace will feel slow. The validation cycles are long. But you are building in the physical world. When you succeed, you don’t have an exit. You have a foundation. You don't just have customers; you have converts. And the product you ship doesn't just generate revenue; it creates a legacy.

If your timelines feel uncomfortable compared to software, that’s because you’re operating inside a system designed to resist change. And let’s not forget you are building actual physical products that interact with a complex world. Times are tough. Don’t give up. We need you.

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Nada Ahmed is the founding partner at Houston-based Energy Tech Nexus.

Houston maritime startup raises $43M to electrify cargo vessels

A Houston-based maritime technology company that is working to reduce emissions in the cargo and shipping industry has raised VC funding and opened a new Houston headquarters.

Fleetzero announced that it closed a $43 million Series A financing round this month led by Obvious Ventures with participation from Maersk Growth, Breakthrough Energy Ventures, 8090 Industries, Y Combinator, Shorewind, Benson Capital and others. The funding will go toward expanding manufacturing of its Leviathan hybrid and electric marine propulsion system, according to a news release.

The technology is optimized for high-energy and zero-emission operation of large vessels. It uses EV technology but is built for maritime environments and can be used on new or existing ships with hybrid or all-electric functions, according to Fleetzero's website. The propulsion system was retrofitted and tested on Fleetzero’s test ship, the Pacific Joule, and has been deployed globally on commercial vessels.

Fleetzero is also developing unmanned cargo vessel technology.

"Fleetzero is making robotic ships a reality today. The team is moving us from dirty, dangerous, and expensive to clean, safe, and cost-effective. It's like watching the future today," Andrew Beebe, managing director at Obvious Ventures, said in the news release. "We backed the team because they are mariners and engineers, know the industry deeply, and are scaling with real ships and customers, not just renderings."

Fleetzero also announced that it has opened a new manufacturing and research and development facility, which will serve as the company's new headquarters. The facility features a marine robotics and autonomy lab, a marine propulsion R&D center and a production line with a capacity of 300 megawatt-hours per year. The company reports that it plans to increase production to three gigawatt-hours per year over the next five years.

"Houston has the people who know how to build and operate big hardware–ships, rigs, refineries and power systems," Mike Carter, co-founder and COO of Fleetzero, added in the release. "We're pairing that industrial DNA with modern batteries, autonomy, and software to bring back shipbuilding to the U.S."

Shell partners with UK-based co. for hydrogen electrolyzer pilot

ultra-efficient electrolyzer

Shell Global Solutions International, a subsidiary of Shell, which maintains its U.S. headquarters in Houston, has signed a collaboration agreement with London-based Supercritical Solutions to advance Supercritical’s ultra-efficient hydrogen electrolyzer technology toward a field pilot demonstration.

In the deal, the companies will collaborate on a paid technology feasibility study that will support the evaluation and planning of the pilot demonstration, according to a news release. Supercritical Solutions’ technology aims to deliver high-efficiency renewable hydrogen at a lower cost for the industrial hydrogen market.

"Signing this collaboration agreement with Shell is a major milestone for Supercritical Solutions and an important step on our commercialisation journey,” Luke Tan, co-founder of Supercritical, said in the news release. “We are directly addressing the cost and complexity barriers facing the renewable hydrogen market. We are excited to move forward with a company like Shell, whose global leadership has been proven to accelerate innovative technologies to market.”

Supercritical’s hydrogen electrolyser technology can operate at high temperatures and pressures of up to 220 bar without the need for an external hydrogen compressor, rare-earth materials or easily degradable membranes. The technology removes the typical compression step in the process while delivering hydrogen at industry standards. It requires significantly less energy than many traditional electrolyzers and is more cost-efficient.

This recent investment builds on an ongoing relationship between Shell and Supercritical. Supercritical was founded in 2020 and was runner-up in Shell’s New Energy Challenge, which helps startups and scaleups develop sustainable technologies, in 2021. Shell Ventures then invested in Supercritical’s Series A funding round in 2024 with Toyota Ventures.

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