I got this interesting chart from an article about how an energy storage company called Eos may revolutionize the way electricity is stored using zinc air batteries. I never knew that so much generating capacity was stored by simply pumping water! The advantage of these batteries is their low cost ($160 / kWh vs. $400 / kWh using lithium batteries). All of this is discussed in terms of making the grid more reliable. I wonder if these batteries are light enough to use in a vehicle?