Southern California Gas Co., a subsidiary of Sempra Energy, earned the top customer satisfaction ranking among natural gas utilities in the West and had the highest score among all utilities nationwide, according to the J.D. Power and Associates “2009 Gas Utility Residential Customer Satisfaction Study.” According to a news release, the study is based on a random survey of U.S. residential natural gas utility customers. In the study, Southern California Gas Co. received a customer-satisfaction score of 671, the highest score among all natural gas utilities. The J.D. Power and Associates study ranks 75 of the nation’s largest natural gas utilities and this year interviewed more than 54,000 customers, according to the release.