by the numbers

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

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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A View From HETI

Texas improved by one spot on WalletHub's Most & Least Energy-Efficient States report for 2026. Photo courtesy of ERCOT

Despite being home to a booming energy sector, Texas ranks below average on a new list of the country’s most and least energy-efficient states.

The list, compiled by personal finance website WalletHub, puts Texas at No. 34 for energy efficiency. It ranked 27th for energy efficiency of homes and 41st for energy efficiency of cars. Texas improved by one spot on the 2026 report, after coming in at No. 35 last year and No. 36 in 2024.

California took the top spot on the list this year, beating out Vermont, which claimed the No. 1 rank in 2025. South Carolina ranked No. 48. Due to data limitations, Alaska and Hawaii were excluded from WalletHub’s analysis.

In the WalletHub study, California had the lowest residential energy consumption per capita and the third-highest efficiency for home energy. At the bottom of the list, South Carolina ranked 48th for energy efficiency of homes and 35th for energy efficiency of cars.

Here’s who joined California in the top 5:

  • No. 2 Vermont
  • No. 3 New York
  • No. 4 Washington
  • No. 5 Massachusetts

WalletHub notes the average U.S. family spends at least $2,000 per year on utilities, and the average consumer spent $2,411 on gasoline in 2024.

The U.S. Department of Energy estimates that adopting energy-efficient measures in the home could reduce a family’s utility costs by as much as 25 percent. As for gas, the agency found a more fuel-efficient vehicle could save the average driver more than $1,000 per year.

“Energy efficiency doesn’t just help save the planet — it also helps save you money by lowering the amount of electricity, gas, oil, or other types of energy you need to consume,” WalletHub analyst Chip Lupo says.

“While there are some steps you can take to become more energy-efficient on your own, living in the right area can give you a big boost,” he adds. “For example, certain states have much better public transportation systems that minimize your need to drive, at least in big cities. Some places also have better-constructed buildings that retain heat better during the winter or stay cooler during the summer.”

WalletHub compiled the listing using data from the U.S. Census Bureau, National Climatic Data Center, U.S. Energy Information Administration, and Federal Highway Administration.

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