Several transmission difficulties?with two emergencies?cropped up last month, the California Independent System Operator?s board learned at its June 16 meeting. On May 22, a transmission emergency was called when Path 26?s transfer capability was exceeded. On May 14, a system emergency was declared in order to stop an overload of generation. A third problem, on May 26, was reduced capacity on the California-Oregon Intertie. Edison is under investigation for the Path 26 emergency, said Yakout Mansour, CAISO chief executive officer. In the May 14 emergency, the Bonneville Power Administration was called in to counterschedule to reduce frequency problems. The intertie problem required help from the Sacramento Municipal Utility District. To date, the grid operator has already charged ?hundreds of millions? of dollars because of transmission congestion, Mansour noted. But, he added, ?It?s better than last summer.? The grid operator?s board voted to change its credit policy for scheduling coordinators, including limiting unsecured credit and calculating credit limits by using long-term rather than short-term ratings. The board also voted to modify its own investment policy to include the ability to invest in money-market funds and commercial paper with terms exceeding five years.