It seems really difficult to make the economics for seasonal electricity storage work. The article mention a materials cost of 23$ per kWh for their battery. Le

It seems really difficult to make the economics for seasonal electricity storage work. The article mention a materials cost of 23$ per kWh for their battery. Let's say this battery lasts 23 years. Transferring 1 kWh from summer to winter would than cost 1$ per kWh. That is before the cost of constructing the battery, R&D, sales, insurance, etc. Cost for 1 kWh is now below $0.10. That would mean generating electricity in summer and transferring it to the winter would come at a 10-fold increase in cost of winter electricity. For any currently available method, it seems that it would be far cheaper to simply have overcapacity in electricity generation from renewables and discard the excess electricity generated in the summer.