Proven Technology
Pumped Storage Hydropower
Most common and well established energy storage technology accounting for 96% of all utility scale energy storage capacity in the United States.
INTER-DAY ENERGY STORAGE SOLUTIONS
Inter-Day Long Duration Energy Storage required in California
Storage required to provide overnight renewable energy
Million metric tons of CO2 per GW of Inter-Day storage which replaces natural gas generation
Goal for California SB 100 requiring supply of 100% zero carbon and renewable energy
Maxwell Energy Storage Project
High-Head Underground Pumped Storage Project
1 - mile below surface
Large Hydraulic Head
The potential energy of a pumped storage plant is directly proportional to the elevation difference between reservoirs. Placing the Lower Reservoir underground allows a 3x increase in power versus a conventional pumped storage plant.
Low Environmental Impact
Underground Reservoir
The combination of a placing the lower reservoir underground and achieving a hydraulic head of ~1 mile results in 70% less surface disturbance and water use versus a conventional pumped storage plant. The design also uses less land than an equivalent battery a battery energy storage system.
US Department of Energy - 2023 Long Duration Energy Storage Report
Energy storage is essential to enabling utilities and grid operators to effectively adopt and utilize the nation’s growing portfolio of clean energy resources, like solar and wind, on demand. However, today’s energy storage technologies are not sufficiently scaled or affordable to support the broad use of renewable energy on the grid. Cheaper, longer, and more efficient storage is needed to meet energy demand that fluctuates throughout the day and night.