Cheaper power bills coming to Delmarva Power customers. The utility company issuing a final report on their electric supply auction, which has providers competing against each other for the right to supply electricity to Delmarva Power. Four companies won the contracts during two separate auctions in November and January. Delmarva Power says based on the competitive bids alone, residential, small commercial, and small general service customers will see about a 4% drop in their monthly average bill. However, Medium and Large general service customers will see an average increase of about 6-7%.