Electricity storage can smooth out fluctuations in supply and can overcome mismatches between supply and demand of electricity. All storage of electricity involves: the transformation of electrical energy into another form of energy, the storage of energy over time, and the reconversion of that stored energy back into electricity. A wide range of technologies is available, including those based on mechanical, chemical and electrochemical processes.
Power storage technologies include hydropower, compressed air energy storage (CAES), flywheel storage systems, chemical storage and super capacitors. Superconducting Magnetic Energy Storage (SMES) is a relatively new power storage technology that stores energy in a magnetic field created by a direct current (DC). Large scale storage for electricity can be combined with photovoltaic plants and managed due to smart grid capabilities. Large scale storage also applies to thermal storage which is a part of district heating and cooling networks powered by biomass boilers with co-generation (CHP) functionalities.