The Port of San Diego is responsible for developing and implementing an Energy Management Plan (EMP) to achieve a variety of economic, social, and environmental goals. A key part of the EMP is electrification of Port activities, particularly the use by ships of onshore electricity rather than their own onboard generators. The Port’s business is highly competitive and shore power electricity demand is very sporadic. Consequently, rate designs with high fixed and demand charges can cause serious economic problems. Nathan was retained to conduct a thorough analysis of the current shore power facilities and rates, proposed new rates and a variety of alternatives. The analysis was based on a detailed simulation of the Port’s business over multiple years, the impact of different facilities and rates on demand for its services and the cost of providing those services, and the potential economic damage to the region from a drop in cruise ship demand. Nathan’s analysis served as the basis of discussions with San Diego Gas and Electric, a joint filing with the Public Utilities Commission, and a customized shore power rate.