Research in molten salts at Danish company Seaborg Technologies originally intended for molten salt nuclear reactors has led to a potential breakthrough that would enable low cost, grid-scale energy storage. The company has developed a method to control corrosion of the otherwise highly corrosive sodium hydroxide, NaOH. Backed by the investment of €10m from current shareholders, Seaborg has launched a sister company, Hyme Energy ApS, to commercially pursue energy storage. The goal is to build a pilot plant within the next 18 months. The first commercial facility is expected to be under construction within three years.

“Our mission in Hyme is to bring inexpensive, large-scale high-temperature energy storage to the market in significant quantities to help solve the challenges of fluctuating solar and wind energy. Thermal energy storage can be key in … accelerating the deployment of wind and solar,” commented Ask Emil Løvschall-Jensen, Hyme CEO and co-founder of both Seaborg and Hyme.

The unique technology in Hyme is a technique for chemistry control that inhibits corrosion by sodium hydroxide. This technology was developed by Seaborg for its next generation Compact Molten Salt Reactor. Hyme expects to be able to halve the price of long-term and large-scale energy storage facilities independently of geographical constraints.

CEO and co-founder of Seaborg, Troels Schönfeldt, said: “Normally no chemist in their right mind would look at anything as corrosive as sodium hydroxide. However, in the development of our reactor, we needed to use sodium hydroxide and were forced to develop these methods.”

Ask Emil Løvschall-Jensen says: “We are pursuing the commercialisation of hydroxides as the key component in large-scale energy storage, and doing it in a separate company allows our new company, Hyme, to focus on succeeding with energy storage while still leveraging the synergies that come with collaborating with our sister company, Seaborg.”

  • Sodium hydroxide is produced from seawater as a by-product of chlorine production and is available at about 16% of the price of the salts currently used for storage. Sodium hydroxide also has a higher specific heat capacity, making it more space efficient. A 1 GWh facility with NaOH occupies a similar footprint to the plot of a typical family house. Together these effects reduce the specific cost of salt as a storage medium by approximately 90%.