The cost of generating power from wind turbines is falling. The rapid rise of wind and natural gas as sources of electricity is roiling U.S. power markets, forcing more companies to close older generating plants. Wholesale electricity prices are falling near historic lows in parts of the country with competitive power markets, as demand for electricity remains stagnant while newer, less-expensive generating facilities continue to come online. The changing American electricity landscape is pressuring power companies to shed unprofitable plants and reshape their portfolios to favor the new winners. Texas provides a clear example. Citing low gas prices and the proliferation of renewables such as wind and solar, Vistra Energy Corp. VST -1.31% , a vestige of the former Energy Future Holdings Corp., said it would retire three coal-fired facilities in Texas by early next year and that it plans to merge with independent power producer Dynegy Inc. Exelon […]