Storing electrical energy by lifting giant concrete blocks onto a stack, then drop them back down to get the energy back - technically possible, but stupid
Not that stupid - Bill Gross (not the bond guy the Idealab guy) started a company doing just that using gravity - https://www.energyvault.com/ They're currently building systems in the US and China - and are working with Meadow Creek Solar to build something in Victoria. From memory, they also have an MOU with BHP.
Looks like you might be a little behind on some of your ideas about what is technically "possible" - maybe you are behind on your ideas with AKP also?
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