Salt breakthrough could halve the cost of storing solar energy
One of the biggest difficulties with wind or solar energy is finding a good way to store it. Lithium-ion batteries are too expensive and need frequent replacing. Molten salt is a more efficient solution — but it tends to be better for storing heat rather than power. If you want both heat and power — for a low price — there have been few good options. Until now.
Seaborg, a small next-generation nuclear startup based in Copenhagen, has discovered a better molten salt storage solution using sodium hydroxide. Hydroxides can contain more heat per salt unit, making it more efficient and reducing the amount of salt needed. It s also about 90% cheaper than the cost of the salts currently used.
“We can more than half the cost of thermal energy storage in one go. And that allows us to come to a stage where we think [our business] can be competitive without any subsidies,” says Ask Emil Løvschall-Jensen, cofounder of Seaborg.
“If we filled up a building the size of the Colosseum in Rome with the salt and heated it to 700 degrees, we would actually be able to supply all of Italy’s entire population with heat and power for ten hours,” says Løvschall-Jensen.
The discovery came as an unexpected byproduct of the work Seaborg was doing on creating small modular nuclear reactors. The startup was set up in 2014 to create compact nuclear reactors on barges, using salt as the component to make them safer than traditional nuclear power plants but also to store the energy.
The problem with salt is that it is corrosive and wears away the steel pipes and tanks used to hold it. Heated to super-high temperatures, the corrosion reactions are sped up even further. Sodium hydroxide isn’t generally used for molten salt nuclear reactors because it is so corrosive, but Seaborg developed a method of controlling its corrosive properties.
The key technology enabler here is the chemistry control that limits the corrosion of structural materials in contact with the molten salt. The chemistry control is developed by Seaborg and is the core IP of the company.