Gravity cars .... On rails
And how about this startlingly obvious idea....
Have a hill, plus excess cheap electricity? Well, put giant blocks of rock into carts and haul them up a hill.
When the juice is needed, roll them back down....
Just like stored hydro, but on rails :)
ARES North America '-' The Power of Gravity
Quote:
The GravityLineTM storage system is made up of multiple 5MW tracks and can vary in size from 5 MW to 1 GW of power and an equivalent range of energy (MWh to GWh) depending upon weight and number of mass cars, slope and distance. ARES’ GravityLineTM design boasts duration flexibility of between 15 mins and 10 hours
https://youtu.be/KMRg4_ZbqYQ