by the numbers
Solar surpasses coal to become ERCOT’s third-largest power source in 2025
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.