By Arpan Varghese and Scott DiSavino (Reuters) -Texas’s power grid operator asked homes and businesses on Wednesday to once again conserve electricity amid stifling heat that has pushed power demand beyond its available supply. For the second time this week, the Electric Reliability Council of Texas (ERCOT), which operates the state’s power grid, said homes and businesses should conserve energy due to expectations that the state’s power resources would not be able to keep up with rising demand. Temperatures across the state were once again above 100 degrees Fahrenheit (38 degrees Celsius), hig…