Energy storage in the western interconnection: Current adoption, trends and modeling challenges

Electric energy storage (EES) technologies have been identified as fundamental components for enhancing the reliability and resiliency of the bulk electric system (BES). Although, EES resources have demonstrated several reliability benefits via increasing the operational flexibility of the power grid, there is a lack of modeling inputs, tools and policy initiatives that restrict their current deployment. These limitations prevent electricity coordinators to fully evaluate EES impacts on system adequacy and reserves planning. In addition, EES developers, investors and utilities face problems in quantifying EES revenues, and in monetizing EES operational value for its multiple grid services. This inability results in lack of EES investments since it is challenging for many market participants to prove EES economic viability against other competing technologies. This paper summarizes the modeling, policy and technology barriers that hinder deployment of energy storage resources and it includes a discussion of possible solutions to address some of these barriers. Finally, a number of modeling and policy recommendations are provided for consideration as part of modeling of EES for stakeholders engaged in current stakeholder driven WECC planning processes.