Mississippi regulators threw a lifeline to Southern Co.’s financially troubled clean-coal power project by temporarily raising customer bills 18 percent for a facility whose backers include the U.S. government, Bloomberg News reported yesterday. Southern’s request to raise rates by $159 million a year was approved on a 2-1 vote by the Mississippi Public Service Commission at a meeting yesterday. The facility in Kemper County would be the first large-scale plant in the U.S. to turn coal into a gas to generate power while capturing carbon dioxide to pump underground. The coal industry was banking on the plant to show the way forward in developing cleaner-burning technologies. The plant has been plagued by delays and is now expected to cost $6.2 billion, almost three times original estimates. Southern’s Mississippi Power utility “stands on the brink of bankruptcy” without the rate relief, said Shawn Shurden, an attorney for the commission staff, reading from a draft of the order. The rate increase is temporary and subject to a refund after the commission examines whether the company’s utility spent prudently.