The consumption of electricity has to be perfectly matched with the generation of electricity. This balance is necessary to maintain a stable and safe electricity supply in all electricity grids. Energy storage can help deal with fluctuations in demand and generation by allowing excess electricity to be stored for periods of higher electricity demand.
Improving the energy system’s efficiency
Energy storage can help to ensure energy security and can help to bring more renewable energy online. By using more energy storage, the energy imports can be decreased and the efficiency of the energy system can be improved by better integrating variable renewable energy sources. Pumped Hydro Energy Storage is the largest-capacity form available and most mature technology for energy storage. Almost all of the installed energy storage capacity is pumped storage, 96 % in 2017 (DOE Global Energy Storage Database).
Optimal existing infrastructure
Conventional pumped storage plant operates with an upper reservoir on a hill and a lower reservoir in the valley. The height difference between two basins is exploited to store energy during periods of oversupply and release it again as required. In this concept, upper reservoir is located in a quarry on surface and lower reservoir is being build 1 400 meters’ depth in underground.
Sites for such plants are limited by the topographical conditions. Hilly and mountainous regions usually are areas of outstanding beauty, so is controversial on account of the high land use associated with them. This concept utilizes existing mine infrastructure and does not alter natural waters as the system is based on closed water circulation.