ABSTRACT
Energy on demand means stored energy, and the most common storage is water in dams, batteries, and biomass. Of course, fossil fuels are stored solar energy from past geological ages. However, what means are available for storing renewable energy today? Storage is a billion-dollar idea, and anyone who comes up with cheap storage will be richer than Bill Gates. Economic storage would mean no new electric power plants would have to be constructed for many years, as energy could be stored from existing power plants during periods of low demand [1-3].
