This project is an entry for the 2022 HackADay Prize. It aims to provide a method for solar power generation and storage without dependence on advanced technologies such as solar cells and batteries. The objective is both for low initial cost, and for long-term maintainability without reliance on the repeat-purchase of new components such as batteries due to reduced capacity with age. Trough style solar concentrators are used to generate steam, the pressure of which is harnessed to store energy in the form of water pressure, to drive a hydroelectric generator.
I think so, although they also mention springs as another form of energy storage.
Woops, I assumed you were the author without even looking. I should probably direct my questions to the comments of the linked article…