Denmark’s molten salt battery was commissioned earlier this year, in the seaport city of Esbjerg. It can store one gigawatt-hour of energy, which is close to what two average coal power station units put out. Although the battery’s electricity is only available for a couple of hours. Whereas a coal power station can keep going for a year without a planned outage.
The Wonder of Molten Salt Battery Technology
The Esbjerg salt battery takes electricity from the distribution grid, and converts this to heat. It then stores this heat in liquidized molten salt at a temperature of 600°C / 1,112°F. This break-through achieved by German and Swiss engineers, could power 100,000 homes for 10 hours with up to 90% efficiency.
Storing thermal energy in molten salt this way, presents an intriguing method to decarbonise our energy sector. It could help speed the transition to a just, clean energy economy. The Esbjerg battery is just one small, successful project down this road. But it does show what we can achieve, when we try.
Charging a Salt Battery
The pioneering salt battery receives electricity from an external source, which is ideally renewable energy. The system uses electrical resistance heaters to heat, and liquidize salt from a tank to 600°C / 1,112°F. It then stores the super-heated, molten salt in a second, insulated tank.
Discharging the Energy
The super-heated molten salt battery releases the stored energy as it flows through a steam generator. The generator converts other water to steam for heating, or electricity co-generation. The salt cools again, and returns to the first tank.
Contributing to Denmark’s Closed-Cycle Economy
Denmark’s molten salt battery contributes to the nation’s expanding closed-cycle economy, by using molten hydroxide salts as its energy-storage medium. These are a low-cost byproduct from producing chlorine. The nation produces tons of hydroxide salts annually, that it currently treats as waste.
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Molten Salt Batteries in a Class of Their Own
