Hydrostor develops 500 MW/4 GWh compressed air storage project in California

From pv magazine USA

Toronto-based Hydrostor has revealed that it has selected Kiewit Engineering Group to advance front-end engineering and design studies for the 500 MW/4 GWh Willow Rock Energy Storage Center. Once completed, the site will be the largest standalone energy storage project in California.

The installation will feature Hydrostor’s Advanced Compressed Air Energy Storage (A-CAES) technology. The company said its equipment can provide affordable, emissions-free long-duration energy storage (LDES). The project will store enough energy to provide power to 400,000 homes over eight-hour durations, storing intermittent wind and solar energy.

Hydrostor’s technology features a four-step process to store and dispatch energy. It initially pulls off-peak or surplus energy from the grid, producing heated compressed air. Then, the heat is extracted from the air stream, and stored inside a thermal store, preserving the energy for later use.

The compressed air is then stored in a tank that via the hydrostatic compensation process to maintain constant pressure during operation.  When the energy needs to be dispatched, pressure forces air to the surface, where it is then recombined with heat, and sent through a turbine, producing dispatchable electricity.

“Hydrostor continues to reach important milestones at Willow Rock, and we look forward to working with the world-class engineering and construction teams at Kiewit to advance this critical clean energy project. Our global teams are paving the way towards achieving aggressive net-zero goals.” said Curtis VanWalleghem, Hydrostor’s chief executive officer. “Willow Rock will be capable of eliminating the equivalent of roughly 120,000 cars off the road every year.”

In January, Hydrostor announced a preferred equity financing commitment of $250 million from Goldman Sachs Asset Management. Goldman Sachs will fund its investment in tranches tied to project milestones to match Hydrostor’s capital needs and accelerate project execution. The funds will also support the company’s global development and marketing initiatives, including the expansion of its project pipeline.

“The need for utility-scale long-duration energy storage is clear,” said Charlie Gailliot, partner at Goldman Sachs Asset Management. “Hydrostor’s A-CAES solution is well positioned to become a leading player in this emerging global market.”

In June 2021, the California Energy Commission said that it would procure 1,000 MW of long-duration energy storage, with durations of eight hours or longer, to be activated during the 2026-28 period.