The concrete blocks are slowly hoisted upwards by motors powered with electricity from the Swiss power grid. As each block descends, the motors that lift the blocks start spinning in reverse, generating electricity that courses through the thick cables running down the side of the crane and onto the power grid. In the 30 seconds during which the blocks are descending, each one generates about one megawatt of electricity: enough to power roughly 1,000 homes.
It can be used to store energy for a while, but there are already other methods that I see more efficient, such as pumping stations to tanks that can provide energy with hydraulic generators, large salt tanks to store excess energy in the form of heat, among others, which have already shown their efficiency for a long time.