To witness the transformation of America's power sector, go to Texas.

Earlier this month, the state's grid operator reported wind had generated more electricity than coal through the first six months of the year.

The announcement is significant on several fronts. Texas is America's largest consumer of coal. The 93 million tons burned by the Lone Star State's power plants in 2017 was more than double that of the 39 million tons consumed by Missouri, the second-biggest coal-consuming state, according to figures collected by the U.S. Energy Information Administration.

Yet coal is declining in Texas. Four large coal plants retired in the state last year. Another, Gibbons Creek, will close down this fall. Where the black mineral generated almost 40% of Texas' electricity in 2010, it was responsible for less than a quarter of the state's power production last year.

Low natural gas prices have been a primary cause for driving coal plants offline. But wind has arguably been the greatest beneficiary. Wind generated 18% of Texas' electricity in 2018, up from nearly 8% in 2010, according to the Electric Reliability Council of Texas (ERCOT).

Wind's rise is all the more notable for the general lack of climate policy in Texas. The state enacted a law in 1999 calling for 10 gigawatts of renewable energy by 2025. Texas already had more than 21 GW of wind installed last year.

"I have made the point once or twice that you don't need a climate policy to effect change," said Ed Hirs, who teaches energy economics at the University of Houston.

Instead of focusing on renewable mandates, as many liberal states have done, Texas put its policymaking energy into transmission. Much of the state's wind is located in West Texas, while its population centers are in the east. A $6.9 billion build-out of 18.5 GW of transmission capacity was completed in 2013, linking west and east. A monthly surcharge on consumers' electric bills financed the expansion.

The transmission build-out was accompanied by a federal tax credit for wind generation, which helped accelerate the deployment of wind across Texas.

"It's just economics. Texas has the wind resource, and Texas decided to invest in the transmission backbone," said Joshua Rhodes, an energy researcher at the University of Texas. "It's like 'Field of Dreams.' If you build it, they will come. Texas built the transmission, and they sure have come."