Cool. I wonder if it makes sense to make a roller-coaster-like potential energy storage system? It sounds like the electric motor-generator problem is solved.

Cool. I wonder if it makes sense to make a roller-coaster-like potential energy storage system? It sounds like the electric motor-generator problem is solved. Escalator technology has many decades of safety and efficiency track record. It also might make sense to use shipping containers full of heavy rubble rather than purpose-built concrete blocks. Container cranes already are designed to work fast and accurately. Containers are common and strong, and solving the saftey problem of weight integrity might be easier.