Arup collaborated with Sumitomo Electric (SEI) to undertake the design review and provide technical expertise for the installation of a 2MW battery storage system in San Diego, California. The storage facility, the largest of its kind in the US, holds enough energy to power over 1,000 homes for up to four hours a day. The project aimed to support California's renewable energy goals, with the battery system acting as a key component in achieving the state's target of 100% renewable energy by 2045. Arup's multidisciplinary approach ensured compliance with California's regulatory standards, addressed technical challenges, and provided spatial planning expertise for the optimal integration of the battery system into San Diego's urban environment. Through collaborative efforts with SEI and San Diego Gas & Electric (SDG&E), the project successfully demonstrated the viability of redox flow battery technology in the US market while supporting a greener future for California.