Pumped Heat Energy Storage System

The GridScale storage system is a pumped heat energy storage system, using crushed rock as an abundant, low-cost storage medium. GridScale is an industrialized and scalable technology for cost-effective storage, offering high round-trip efficiency with no geological or topological constraints.

The system’s main components:

• A turboexpander unit with pre-pressure compressor, controls etc.
• A filter unit with air filters and manifolds.
• Two rows of standardized storage reservoirs.

The storage duration is adjusted with the number of storage tanks. Power rating is adjusted with the number of parallel units.

The GridScale range covers both the 12-18 h duration required for day-to-day smoothing of solar PV, and the 3 to 7 days duration required for smoothing of wind power over gaps caused by low wind periods.

The hot storage reservoir material is crushed basalt rock. Basalt is formed by the cooling of lava, and due to its volcanic origin, it is very resistant to rapid heating and cooling. Basalt is abundant and easily accessible, and it is readily available in large volumes all over the world.