By Will Wade and Brian K. Sullivan From Bloomberg News Texas is pushing homes and businesses to conserve electricity for a second day in a row to stave off blackouts as a punishing heat wave bakes the western U.S. Temperatures will top 100 degrees Fahrenheit (38 degrees Celsius) from Montana to Southern California Tuesday, according to the National Weather Service. Dallas will reach 99. With many power plants unexpectedly down for repairs, officials warn the grid may fall short. It’s the second time since the deadly February blackouts that Texas is pleading for conservation. “These are really hot temperatures, and there is really no break for the potential record heat until Sunday,” said Bob Oravec, a forecaster with the U.S. Weather Prediction Center. The searing weather marks the first heat-related stress tests of the year for U.S. power grids as a historic drought grips the western half of the nation. …