Sumitomo Electric Industries, Ltd. and New Energy and Industrial Technology Development Organization (NEDO), in cooperation with the State of California and public utility company San Diego Gas & Electric (SDG&E), started the demonstration of the United States’ largest redox flow battery system in California, and a commencement ceremony was held at the project site on March 16, 2017.
Following the start of the project in September 2015, a redox flow battery system (2 MW x 4 hours) was constructed for a power grid at a substation in San Diego. Demonstration will now be carried out to evaluate the management of surplus electricity and regulation of grid frequency and voltage fluctuation. Data on performance in the transmission and distribution grid will also be collected to improve the system’s economic value.
2 MW/8 MWh redox flow battery system
1. Background
The State of California has set a goal of increasing its renewable portfolio standard, excluding large-scale hydropower generation, to 33% by 2020 and 50% by 2030. These goals are the second-highest renewable energy integration goals after the State of Hawaii. However, issues resulting from increased integration of solar power, including rapid fluctuations of demand and supply balance that occur in the morning and evening (the so-called Duck Curve) as well as low-quality electricity, have become more evident. For this reason, utilities are now required to install large-scale energy storage systems under California’s Assembly Bill 2514.*1 In addition, public utility organizations are required to collaborate in developing a storage battery roadmap with the aim of expanding revenue opportunities for storage battery systems.
Against this backdrop, NEDO concluded a memorandum of understanding with the State of California Governor’s Office of Business and Economic Development (GO-Biz) for the Demonstration Project for Validation of Redox Flow Battery Performance in California in September 2015. NEDO entrusted its work for implementing the project to Sumitomo Electric, and the project demonstrates the multiple-use of the storage battery system for the transmission and distribution grid in San Diego to improve its economic value and disseminate the system.
NEDO and Sumitomo Electric, in cooperation with the State of California and local utility company SDG&E, started the demonstration of the project on March 16, 2017.
2. Overview
The redox flow battery system developed for the project is the largest of its kind in the United States. With the assistance of SDG&E, the redox flow battery was constructed for the storage battery system to be connected to the grid at the substation for performance verification. As the redox flow battery has excellent durability and is extremely safe and suitable for both fast response and long duration applications, it is expected to be an effective solution to addressing issues that result from increased integration of renewable energy. More specifically, distribution grid multiple operations, such as management of surplus electricity and regulation of frequency and voltage fluctuations, will be analyzed to determine its technological effectiveness and economic efficiency. Following this, the redox flow battery system will be controlled by an independent system operator to demonstrate the contribution to ancillary services*2 in market participation and to improve the system’s economic value. Totally, the demonstration evaluates the multiple use of the storage battery system for the transmission and distribution grid.
Through the project, NEDO aims to resolve issues related to the increasing integration of renewable energy, such as surplus energy as well as frequency and voltage fluctuations, while analyzing the redox flow battery system to improve cost-effectiveness.
