Engineers Harness Sodium Hydroxide for Sustainable Energy Storage

The system uses heat instead of generating electricity and can achieve efficiencies exceeding 90%


A Denmark-based firm, Hyme Energy, has developed a novel energy storage system that uses a type of salt known as sodium hydroxide, known to have exceptional heat storage capabilities and can withstand temperatures up to 1,292°F.

Hyme Energy’s storage system can store more energy by utilizing this high-temperature salt, making it more efficient than conventional systems.

Additionally, sodium hydroxide is cost-effective, improving the system’s overall efficiency.

The company said that when Hyme’s system uses heat instead of just generating electricity, it can achieve efficiencies exceeding 90%. It currently has its sights set on the industrial and residential markets that require heat.

Numerous potential storage solutions are being developed, including large-scale batteries and compressed air storage in underground vaults, all of which aim to ensure an uninterrupted electricity supply during low wind and solar power availability.

The team said this energy storage system could amass significant amounts of energy and hold it for up to 24 hours, surpassing the eight-hour discharge capability of lithium-ion storage systems.

Molten salt represents an alternative energy storage method, which involves heating the salts using excess energy from solar and wind sources and later utilizing the stored heat to power a turbine when there is an energy shortage.

Molten salt technology is already utilized in concentrated solar power systems.

However, a significant drawback of this method is that the most used salts, namely sodium nitrate and potassium nitrate, must reach a higher temperature, resulting in a low efficiency of approximately 70% for electricity delivery.

Demonstration System 

Hyme Energy is working on two demonstration facilities for its innovative energy storage system.

The first is a 1.5-MW storage unit in Esbjerg, which will be commissioned this year as an integration project to test components and system integration. The second, a larger 15-20 MWh facility, is planned for Denmark’s energy island, Bornholm, in 2024.

Hyme’s system uses two storage tanks and sodium hydroxide, a cost-effective and efficient salt. It will replace an oil boiler in a cogeneration plant, providing the district with steam, power, and heat.

Seaborg Technologies, Hyme’s sister company, has developed a corrosion control system that allows molten salt to be used in small modular nuclear reactors without causing damage.

If successful, this energy storage method could reduce reliance on fossil fuels and provide power during low wind and solar energy.

Researchers at the Fraunhofer Institute for Solar Energy Systems (ISE) have developed a solution that combines power from renewable sources with electricity from the public grid and uses batteries to compensate for fluctuations.

Earlier this month, researchers at the Shandong Academy of Medical Sciences, China, and Kyushu Institute of Technology, Japan, claimed to upcycle crab shells into porous, carbon-filled materials with various uses, including using the crab carbon to create anode materials for sodium-ion batteries.