Hydrostor's Massive Compressed Air Project

On February 12, 2026, Canadian energy startup Hydrostor signed a 50-megawatt offtake agreement with California Community Power for its Willow Rock Energy Storage Center, a 500-megawatt advanced compressed air energy storage facility under development in Kern County, California. The project stores energy by compressing air into underground caverns at depths of 2,000 feet, backed by a 600 acre-foot surface reservoir. With more than 8 hours of storage capacity from a 500-megawatt facility, Willow Rock represents a new class of long-duration energy storage that directly competes with the baseload power role traditionally filled by coal plants.

Cost Competitiveness Is Already Here

According to BloombergNEF's 2024 data, compressed air energy storage at 8-hour duration costs approximately $293 per kilowatt-hour, while lithium-ion batteries at 4-hour duration cost $304 per kilowatt-hour. Thermal energy storage comes in even lower at $232 per kilowatt-hour. These figures illustrate that long-duration storage technologies are not only technically viable but already cost-competitive with the lithium-ion batteries that have dominated the market. For coal advocates, this means the economics of building new coal capacity are increasingly unjustifiable when storage can deliver comparable reliability at competitive or lower costs.