3 ms·I think it means Pumped Energy Storageby croddin 6y agoI think it means Pumped Energy Storagenawgz 6y agoI was wondering if he was suggesting we roll trains up hills with excess power and use regenerative braking or something like this, I hope he will respondjlmorton 6y agoNo need for a hill! You can dig a deep hole, and fill it with concrete weights.