13 July 2007 — The Associated Press reported that Duke Energy says it successfully tested soybean oil in one of its backup power plants that typically runs on diesel or natural gas. Duke said the tests this week at Mill Creek, a combustion-turbine peaking plant in South Carolina, were the largest U.S. trial of biodiesel on a plant of that type and size.

Duke tested 100 percent biodiesel and three biofuel-diesel blends ranging from 20 percent to 80 percent biodiesel. Before it can become part of the plants’ fuel mix, biodiesel would have to show financial, operational and emissions benefits, said Mary Huller, Duke’s project manager. The company said it still has some technical issues to work out, particularly with the fuel blends containing mostly biodiesel.