Storage Systems for Integrating Wind and Solar Energy in Spain

Renewable energies are on the rise in many countries. Mainly due to environmental concerns they have obtained the political support and are fostered in a large number of countries. Among the technologies which have experienced the highest rise are intermittent generation technologies which are variable and uncertain in their electricity production, such as those using wind or solar power. These characteristics require a radical change of the way electricity energy systems are organized nowadays. More flexibility is needed to adapt to these fluctuating and only to a certain extent controllable energy technologies. Storage systems offer perfect conditions for the integration of these intermittent energy sources. Electricity generation surplus from these technologies can be stored and injected into the electricity system later when demand or prices are higher. Investigation in new storage systems is necessary to analyse which storage systems may adapt best to this type of fluctuating production. This article aims to compare some already mature storage technologies and their impact on the integration of renewable energies in the operation of the electric system. In specific, we will analyse the following four storage technologies: pumped hydro storage, compressed air energy storage, heat storage in combination with concentrated solar power and lithium-ion batteries which are operated stationary as well as in electric vehicles. Cost savings, emission reductions and the effect on the production of other generation technologies will be observed.