Lifting heavy weights with a crane (or up a hill with a train) is unfortunately a very expensive way to store energy compared with pumped-storage hydroelectrici

Lifting heavy weights with a crane (or up a hill with a train) is unfortunately a very expensive way to store energy compared with pumped-storage hydroelectricity, which does effectively the same thing but with far lower cost and greater scalability. This can be seen from the fact that while lifted weight storage is ridiculously easy to build with existing technology - it's a train or a crane, after all! - it has never caught on as an economically fieldable system, whereas pumped-storage hydro has wide adoption.