The amount of electricity produced and the amount demanded by consumers is often different. This causes surpluses of energy at one moment and shortages at another. Energy storage can help deal with these fluctuations in demand by allowing excess energy from times of lower demand to be 'saved' for consumption in periods of higher demand.
The EU has an installed capacity of 50 GW of storage, which corresponds to about 5% of our daily generation. By using more energy storage, the EU can decrease its energy imports and keep prices low by better integrating intermittent renewable energy sources and increasing the efficiency of electricity transmission.
How energy storage works – hydro storage
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/en/files/pumped-hydro-storage-limberg-austriajpgPumped hydro storage in Limberg, AUSTRIA.jpg
In pumped storage, a power plant producing more electricity than demanded will use the excess electricity to pump water from a lower basin to a higher basin. This water is then stored in the higher basin in the form of gravitational potential energy. When energy demand increases, the water is released back down through the pipes, passing through underground turbines on the way. These turbines spin a generator which converts the gravitational potential energy into electricity.
Hydro storage can store large amounts of energy. But when the grid requires this energy, hydro storage may not deliver it fast enough. This is because hydro storage takes minutes to start up when milliseconds are often needed. It therefore needs to be complemented by batteries and other technologies that react faster.
Energy storage projects may receive funding from the almost €6 billion allocated to energy under the EU's Research and Innovation Programme Horizon 2020.