Energy storage needs of power generation companies

For instance, when the clouds suddenly appear or the wind stops blowing then the energy production from photovoltaics and wind turbines will be decreased dramatically. Thus, energy storage can allow energy to be stored during high renewable generation or low demand periods, and to be used during low renewable production or high demand periods .

Conclusions Energy storage is the key element for a new smart power world, based mostly on forms of renewable energy. Most of the energy storage technologies are technically developed and commercially available, but are not mature yet. Most of them are still an expensive solution and need more investigation on their durability and reliability.

Energy storage systems allow energy consumption to be separated in time from the production of energy, whether it be electrical or thermal energy. The storing of electricity typically occurs in chemical (e.g., lead acid batteries or lithium-ion batteries, to name just two of the best known) or mechanical means (e.g., pumped hydro storage).

In other words, the energy is stored when there is excess in renewable energy production and it is released to the grid during periods of high demand (Fig. 20). The storage technology must be scalable and able to provide energy for some minutes to some hours.

Table 1 and Table 2 contain the characteristics of all storage methods. A comparison of all energy storage technologies by their power rating, autonomy at rated power, energy and power density, lifetime in cycles and years, energy efficiency, maximum DoD (permitted), response time, capital cost, self-discharge rate and maturity is presented.

All storage technologies can reinforce the quality, stability and reliability of the grid electricity systems. However, the proper storage method should be selected based on several parameters, such as the capital and operational cost, the power density, the energy density, the lifetime and cycle life and the efficiency.