Moonwatt Launches Sodium-Ion Storage for Utility-Scale Solar in Munich

Dutch startup Moonwatt showed a sodium-ion storage system built for utility-scale photovoltaic (PV) plants at the Smarter E trade show in Munich, Germany. The centerpiece is the Monopod 1500 V / 4-hour Hybrid, a DC-coupled unit aimed at operators of large solar arrays.

Moonwatt says the DC-coupled setup trims electrical balance-of-plant costs by half and rates the system for 12,000 charge cycles. On efficiency, the company puts the DC-coupled path at 94% from solar through the battery to the grid, while an AC-coupled version reaches 93% along the same route.

The cells use sodium iron phosphate pyrophosphate, a polyanion sodium-ion chemistry that contains no lithium, cobalt, nickel, or manganese. Those four metals are staples of lithium-ion cells.

According to Moonwatt, the passive cooling design loses up to 25% less energy per cycle than a conventional actively cooled lithium-ion system. Skipping active thermal management removes the parasitic draw that cooling equipment pulls from each charge and discharge.

Output scales with how many Monopod units sit behind each inverter block. Battery AC power runs from 50 kW to 354 kW, and AC energy capacity from 202 kWh to 1,416 kWh. Developers can size a single inverter block or chain several for larger installations.

Moonwatt will display the Moonpod at Intersolar Europe in Munich from June 25 to June 27 at Booth C2.190, according to pv magazine. The company is pitching the product on cell chemistry and cooling method, not on raw energy density.