Producing electricity from heat is a high loss operation. Storing heat is only logical when the source energy is heat. This is what wikipedia means by 1% loss p

Producing electricity from heat is a high loss operation. Storing heat is only logical when the source energy is heat. This is what wikipedia means by 1% loss per year. Meanwhile kinetic storage has no loss over time. As a bonus converting kinetic energy to electricity is rather efficient. So far Pumped-storage hydroelectricity is our best method for large scale electricity-to-electricity storage.