For the second time this year, the Electric Reliability Council of Texas (ERCOT) asked state residents to voluntarily conserve energy to avoid rolling blackouts ahead of expected record heat in the state. ERCOT, which runs the state’s power grid, issued a “Conservation Appeal” Sunday. The appeal asks “Texans and Texas businesses to voluntarily conserve electricity, Monday, July 11 between 2-8 p.m.”

“ERCOT also issued a Watch for a projected reserve capacity shortage from 2-8 p.m.,” ERCOT said Sunday. “The heat wave that has settled on Texas and much of the central United States is driving increased electric use. Other grid operators are operating under similar conservative operations programs as ERCOT due to the heatwave.”

Temperatures across the state hit records on Sunday, reaching 105 degrees at Houston’s Bush Intercontinental Airport. High or dangerous heat levels were forecast for much of the state on Monday, with temperatures expected to exceed 100 degrees.

“I have asked all City departments to prepare in case the state’s power grid fails during extreme heat tomorrow,” Houston Mayor Sylvester Turner said in a Sunday tweet. “The City of Houston’s Office of Emergency Management, police, fire and other departments are checking fuel and operational generators.”

It’s not just the heat that has ERCOT concerned about rolling blackouts in Texas. The power grid operator is also concerned about low wind.

“While solar power is generally reaching near full generation capacity, wind generation is currently generating significantly less than what it historically generated in this time period,” ERCOT said in its Conservation Appeal. “Current projections show wind generation coming in less than 10 percent of its capacity.”

The two ERCOT warnings come over a year after a winter deep freeze in Texas knocked out power to millions and forced rolling blackouts in the Midwest. More than 200 people died as a result of the crisis.

Earlier this year, ERCOT reassured resident that it had enough reserves to meet demand this time around. However, the North American Electric Reliability Corporation’s (NERC) 2022 Summer Reliability Assessment, indicated the western United States is “at ‘elevated risk’ of energy emergencies during extreme conditions” like a heatwave over the summer.

Reuters contributed to this report.