THOMAS SHEA/AFP via Getty Images A watchdog for Texas' power-grid operator said it overcharged as millions went powerless. The Electric Reliability Council of Texas is not federally regulated. The report said power prices were set at $9,000 per megawatt per hour, the highest price possible. Potomac Economics, an independent market monitor for Texas' Public Utility Commission said that the state's power-grid operator massively overcharged residents as the state was rocked by a deep freeze and power grid failures in late February. The overcharges came in at a total of $16 billion, according to the filing. The report recommended that the Electric Reliability Council of Texas (ERCOT) take measures to reverse the charges.