NEDO Extends Redox Flow Battery System Project to Conduct an Additional Demonstration of a Microgrid as a Solution to Power Outages in California
–World's First Dual-Use Operation of a Battery System with a Microgrid and Its Value on the Electricity Wholesale Market–

In California, U.S.A., the government has passed Senate Bill No.100 declaring an ambitious policy stating that renewable energy and zero-carbon resources will supply 100% of electricity consumed by California’s end-use customers and state agencies by 2045. The government has also been promoting the introduction of energy storage facilities as a solution to the problem of power quality deterioration caused by the mass adoption of renewable energy.

In September 2015, NEDO concluded a memorandum of understanding with the California Governor's Office of Business and Economic Development (GO-Biz). Under this agreement, the demonstration project^*2 has been conducted in San Diego, California in cooperation with Sumitomo Electric Industries, Ltd. and San Diego Gas & Electric Company, a major power utility company.

In California, planned power outages have been implemented as measures to prevent disasters such as major wildfires(Public Safety Power Shutoff) in recent years and rotating power outages were conducted to lessen energy demand during extreme heatwaves, which are becoming a social problem. In the past, certain customers with critical loads such as data centers have implemented protections against power outages, but there is an additional need for countermeasures against widespread power outage and for strengthening the resilience of power grids. One solution is a microgrid with energy storage systems that power isolated distribution lines.

As part of the planned microgrid demonstration^*3, in order to analyze any technical issues, part of the distribution network which the RFB system with an energy capacity of 8 MWh and approximately 70 consumers are connected will be isolated from the grid. The RFB system has been participating in the California Independent System Operator (CAISO) market since December 2018. Redox flow batteries have the advantages of charging and discharging patterns and the number of cycles not causing degradation, and real time measuring of the remaining charge. This allows flexible bidding patterns without operational constraints in the markets which has led to innovative bidding strategies to improve revenue in both the energy and ancillary services^*4 markets being developed and successfully demonstrated. The project aims to demonstrate the commercial value of the RFB system in which the power utility company can generate revenue from the CAISO markets during normal times in addition to providing back up power from the microgrid to customers in emergency situations.

This “dual-use” capability will become the world’s first demonstration of its kind, and we hope to contribute to the greater market penetration of energy storage based on the innovative achievements of the project.

NEDO and Sumitomo joined GO-Biz and SDG&E to issue an additional joint press release which can be accessed at: Groundbreaking Flow Battery Project Helping To Advance Clean Energy Microgrids

We will develop the system by fall 2021, when wildfires are common, and conduct the microgrid demonstration until December 2021. RFB technology is not only applicable in the U.S. but also in isolated microgrids with solar and wind power facilities and in 100% renewable islands all over the world. After the project, we will apply the technology to these fields, promote the introduction of energy storage, and contribute to the expansion of renewable energy and the reduction of greenhouse gas emissions as well as the strengthening of power grid resilience.

NEDO Smart Community Department
Tel: +81-44-520-5274 e-mail: smartcommunity@ml.nedo.go.jp

Sumitomo Electric Industries Energy System Division
Tel: +81-6-6466-5628