A Californian company proposes using weighted electrically-driven rail vehicles on inclines to store energy. At times when the capacity of electricity supply exceeds demand the vehicles would be driven up inclined tracks, and when demand exceeds generation they are allowed to run down, generating electricity as they fall.
This link includes a video that shows a prototype vehicle (which appears to be built on a conventional locomotive chassis), an interview with a promoter, and an animation of a "farm" of these devices. There is a shortage of hard data, such as how much energy could be stored, for how long, and how steep the tracks are, etc., but a quick calculation shows that some thousands of these vehicles would be required for them to be useful. The control panel for this prototype has a power dial that appears to go up to only 20 kW. The promoter in the interview focuses instead on how the construction material can be recycled at end of life.
(Score: 2) by Immerman on Tuesday July 03 2018, @07:22PM
It's useful in areas where water is scarce? Or where geologic concerns make storing large quantities of elevated water difficult or dangerous? Or if you have low slopes so that any substantial elevation change requires a dramatic horizontal displacement, then there's also the possibility that rolling resistance will be considerably lower than the flowing resistance in pipes.