An Energy Storage Cost Comparison: Li-ion Batteries vs Distributed Load Control

In 2017, San Diego Gas & Electric installed a 30 MW, 120 MWh lithium-ion battery storage facility–the world’s largest at the time. But, recent work demonstrates that local control can enable flexible loads to provide equivalent battery-like services to the grid. Our cost comparison shows that it is much cheaper to acquire 30 MW, 120 MWh of capacity by retro-fitting 120,000 water heaters with control hardware and telecommunications. Surprisingly, it may even be cheaper to give away 120,000 ‘smart’ water heaters!