As new electricity generation skews toward solar and battery storage in Texas, Republican state senators are questioning whether it’s time to impose minimum standards for building gas plants and move away from free trade in the state’s electricity marketplace.

The Electric Reliability Council of Texas (ERCOT), the state’s grid operator, reported last week that 70 percent of generation in the 460-gigawatt interconnection queue is from solar and battery storage. Natural gas facilities make up less than 17 percent of that line. And while it’s an uptick from three years ago, when there were less than 10 gigawatts of gas power plants seeking to connect, legislators and grid leaders say going forward the current level of planned gas facilities won’t be enough.

State Sen. Phil King, a Republican from Weatherford, asked the leaders of ERCOT and the Public Utility Commission of Texas (PUC) at a public hearing last week whether there should be a rule that puts a quota on what share of new generation connecting to the grid comes from fossil fuels.

“Should we say that from a point of interconnection that 50 percent—or some percentage of new generation—has to be dispatchable generation as opposed to just letting the market forces guide that,” King asked, referring to gas plants as “dispatachable” because they can be ramped up or down on demand, unlike intermittent wind and solar power sources.