Texas may be the center of the U.S. oil and gas industry, but the latest data shows that the state's competitive energy market is increasingly favoring clean energy over fossil fuel alternatives.

New information from state grid operator ERCOT shows that carbon-free resources made up more than 30 percent of its 2018 energy consumption, and a slightly larger percentage of its 2019 generation capacity. In both cases, the largest share of credit goes to the state’s massive wind farms, which provided 18.6 percent of 2018 energy and make up 23.4 percent of 2019 capacity, followed by nuclear power, which served 10.9 percent of last year’s needs and will provide 5.4 percent of this year’s capacity. 

Solar, meanwhile, only made up a sliver of the 1.3 percent of last year’s energy use served by “other” resources such as hydropower, biomass and fuel oil. But solar will make up 2.1 percent of this year’s generation capacity, in a testament to the small but fast-growing utility-scale solar market developing in the state. 

ERCOT's achievement is largely a result of the economics of wind and solar power, plus a healthy dollop of state energy policy to integrate its western wind resources to eastern cities, known as competitive renewable energy zones (CREZ). 

Since 2009, about when CREZ got started, wind generation capacity has grown from 6 percent to nearly 20 percent of ERCOT’s energy mix, while coal has fallen from 37 percent to 25 percent of ERCOT’s energy mix over the same time. 

Meanwhile, the amount of wind being curtailed due to lack of transmission and demand has shrunk from about 17 percent in 2009 to less than half a percent in recent years, a result of the $7 billion in new transmission enabled by CREZ, as well as ERCOT's work to build weather forecasting and demand management into how it manages its grid. 

When it peaks, Texas’s wind fleet can actually power more than half of ERCOT’s grid, even if it’s in the dead of night. In December, at 7 minutes after midnight, wind power generated 19,168 megawatts of electricity for a moment, beating ERCOT’s previous record of 17,920 megawatts on a midafternoon the month before.

December’s record-setting wind output equated to a maximum generation percentage of 54.64 percent at the time, according to Joshua Rhodes, research associate at the Energy Institute at the University of Texas at Austin, who recently highlighted the latest ERCOT numbers in a tweet.

“The more interesting thing is that almost 55 percent of demand in the ERCOT system was being serviced by wind,” he said in a Tuesday interview. “That’s something that grid operators and policymakers have been scared of. […] We’ll never be able to control wind and solar, but the more we can predict them, the more I think we can trust them.” 

Solar meets only a fraction of ERCOT’s needs compared to wind, but its growth rate is much faster at present, with utility-scale projects in the state setting new low-price records alongside solar leaders like California, Arizona and Nevada. Much of this solar is in West Texas, where it can benefit from the same transmission investments that have enabled the wind industry, Rhodes noted. 

In fact, ERCOT's December 2018 interconnection queue had more solar projects than wind projects in it, which is the first time that’s happened, he said. That’s largely driven by the drive to get projects in place to capture the full benefits of the federal Investment Tax Credit for solar power and Production Tax Credit for wind power, which start to wind down in 2020. 

Of course, interconnection request figures must be taken with a grain of salt, since they’re always winnowed down as they move from proposals to fully financed projects supported by an interconnection study. Still, in terms of the proportion of new projects being planned, it’s a gigantic change from the interconnection queue that existed only four years ago, when natural-gas power plants were still the dominant form of new generation being planned. 

Renewable energy developers in Texas also won a regulatory victory this week. The Public Utility Commission of Texas denied a proposal by utilities Calpine and NRG to change the way transmission line losses are calculated for ERCOT-interconnected generators, a move that could have reduced the value of wind and solar located far from the state’s population centers.