Today it is broadly recognized that the share of renewable energy sources in the power grid is going to increase substantially and will reach high percentages in the future production mix. Expansion of storage technologies is often considered pivotal to allow for this renewables European power grid.
The operating characteristics of storage technologies have been attractive to grid operators as they provide them with resources that can adapt quickly to supply and/or demand changes. This feature has positioned them as a candidate for mitigating the variability of renewable generation. The fundamental operation of a storage technology is to convert and store electricity in another form and re-convert back to electricity at times when it is mostvaluable. Electricity can be stored through mechanical, thermal, electrical and chemical storage. A number of technologies that have emerged from these options including pumped hydroelectric, compressed air, flywheel, batteries and hydrogen.
According to its operational characteristics, each technology can respond to certain needs of the system, like balancing, capacity displacement and arbitrage. However, the current cost of most storage technologies in combination with the lack of a coherent business model and favorable market conditions have proved to be insurmountable obstacles for investors. Nevertheless, the expected large renewables market will require a significant amount of flexible generation assets. This will essentially keep storage in the forefront and push all relevant stakeholders to overcome any technological, operational and/or policy challenges.