ABSTRACT
Energy storage becomes necessary whenever there is a mismatch between the energy available and the demand. Storage is especially important in solar energy applications because of the seasonal, diurnal, and intermittent nature of solar energy. Nature provides storage of solar energy in several ways, such as plant matter, also known as biomass, ocean thermal energy, and hydro-potential at high elevation by evaporation from water bodies and subsequent condensation. Even fossil fuels are a stored form of solar energy as they are produced from biomass. Natural solar energy storage provides a longer-term buffer between supply and demand. Since the availability of solar energy varies by the time of the day and by the time of the year (seasonal), and can have intermittency even during a day due to clouds, energy storage systems can be short term or long term, depending on the objective.
