In October 2013, the California Public Utilities Commission (CPUC) issued rules for its jurisdictional utilities to procure a minimum of 1,325 megawatts (MW) of energy storage systems by 2020. The goal of this study is to examine the operational value of this storage portfolio in California and the rest of the Western Electricity Coordinating Council (WECC) region. Modeled results show that the storage portfolio, when providing energy and operating reserves, reduces the total WECC-wide production costs by $78 million per year in the 33% renewable portfolio standard scenario. This value increases to $144 million per year in the 40% renewable portfolio standard scenario, primarily because of the increase in off-peak and peak price differences that are due to additional solar generation. These values are equivalent to $59/kW-year for the storage portfolio for the 33% scenario and $109/kW-year for the 40% scenario.

Technical Report