Solar tops coal
Texas power grid marks milestone in energy transition
Solar panels supplied more electricity than coal-fired power plants to the Texas power grid in March for the first time, marking an important milestone in state’s energy transition.
Electricity generated from the sun’s energy sent 3.26 million megawatt-hours onto the Electric Reliability Council of Texas grid last month while coal-fired facilities generated 2.96 million megawatt-hours, according to researchers with the Institute for Energy Economics and Financial Analysis, a nonprofit think tank promoting the transition to a sustainable energy economy. One megawatt can power about 200 Texas homes on the hottest summer days, according to ERCOT, which operates the grid supplying 90% of the state’s electricity.
Solar’s share of the ERCOT wholesale electricity market topped 10% in March, while coal’s market share fell below 10% for the first time, to 9.1%. IEEFA researchers Dennis Wamsted and Seth Feaster called the trends linked and highly consequential.
“These shifts in power production — solar’s increasing role, and coal’s decline in the nation’s most power-hungry state — show just how substantial the changes have become in the energy transition,” Wamsted and Feaster wrote.
Electricity generation is the second-largest source of the country’s climate-warming emissions, released by burning fossil fuels such as natural gas and coal in power plants. Natural gas remained the primary resource on the ERCOT grid in 2023, providing 45.6% of the state’s electricity. Wind power came second, contributing 24% of ERCOT’s fuel mix, while coal output came third, contributing 13.9%.
In recent years, solar power has increased dramatically on the ERCOT grid as the cost of building grid-scale solar farms has dropped. Solar’s contribution to the Texas power grid began to show up in ERCOT’s power generation data around 2016 and 2017, according to
Wamsted and Feaster. In 2017, solar generated just 0.6% of the electricity Texans demanded from ERCOT, or 2.26 million megawatt-hours that entire year. In comparison, solar accounted for 7.3% of resources fueling the grid in 2023, according to ERCOT data.
Coal’s share of the ERCOT market, meanwhile, has been falling “almost in reverse lockstep to solar’s growth,” the researchers wrote. From 2003 to 2014, coal made up 36% to 40% of ERCOT’s fuel mix each year — that dropped to 25% by 2018, under 20% in 2020 and 13.9% last year.
“We’ve been building solar at a pretty breakneck pace in the state, and there’s actually not a
coal plant under construction in the entire country,” University of Texas at Austin research scientist Joshua Rhodes said. “It shows what the market is wanting to build, not only in places that are more market-driven like Texas but even in other parts of the U.S. that are not.”
Coal’s decline is especially significant in Texas, which has long been the largest user of coal for electricity production in the U.S. Even in 2023, Texas burned 50.7 million tons of coal for electricity, more than twice the amount used in second-place Missouri and 13% of the national total, according to Wamsted and Feaster.
Still, Rhodes, who was not involved in the IEEFA study, said he expects that on average in 2024, coal-fired generation will exceed solar generation in the ERCOT region.
That’s because Texas has yet to hit the hot summer months, when coal-fired power plants out for maintenance in the spring will fire up to meet high electricity demand as Texans turn up air-conditioning.
By 2030, though, Rhodes said his modeling shows solar generation catching up to wind and contributing 20% to 30% of total electricity generated in Texas. That estimate is based in part on the more than 155,000 megawatts of solar projects in the ERCOT pipeline, compared to the approximately 22,700 megawatts of solar capacity operational now, he said.
“Solar looks like it’s getting built faster than wind did in its earlier years, so I expect it to grow faster, as long as we don’t get in the way of ourselves,” Rhodes said.