Since the dawn of electricity generation a need for energy storage has existed, but options were limited.
In the mid 1900s, suppliers began using pumped hydro storage plants. Capacity-wise these plants constitute over 90% of all installed storage today. However, when distributed renewables emerged as a trend in electricity generation during 2000, people sought more efficient forms of energy storage.
This chart shows the global number of operational installed storage projects as of April 2016, as reported in the DOE global energy storage database.