How does energy storage work?

If generating renewable energy is important, it is even more important to have it available to users thanks to energy storage, but do we know how it works?  Our society

The U.S. will triple its energy storage capacity in three years

The United States, the world's largest economy and the second-largest consumer of electricity on the planet, is laying the foundations for a future in which its power grid will be increasingly connected to energy storage sources. Indeed a report by the U.S. Energy Administration (EIA) estimates that the United States will triple its energy storage capacity in just three years.