An inexpensive and scalable saltwater flow battery for applications in renewable energy, telecommunication towers, oil well pumps, agriculture irrigation pumps and other sectors has been unveiled by startup Salgenx. The batteries offer an alternative to the use of higher cost lithium, vanadium and bromine and can be deployed for standalone storage or with solar or wind power.

The Salgenx S3000 offers a storage capacity of 3,000 kWh at a production cost of $100 kWh. Delivering an energy density of 125.7 Wh/liter, the seawater flow battery system requires two large tanks filled with fluid electrolytes, one of which is saltwater and the other a proprietary electrolyte. The fluids are circulated through electrodes, which regulate the input and output of electricity from the battery. The membrane-free devices can be scaled by adding more electrodes and additional electrolyte tanks and can be engineered in 250 kW, 3 MWh, 6 MWh, 12 MWh and 18 MWh configurations.

Source: Salgenx

The technology is claimed to have a life expectancy of more than 25 years and a roundtrip efficiency of 91% at 10 mA/cm². The saltwater tank can be used simultaneously for thermal storage in combination with a heat pump using carbon dioxide as a refrigerant.