The biggest obstacle to energy production going 100 percent green is the irregularity and unpredictability of renewable energy sources, and storage systems – which store energy when production levels are at their highest and supply that energy when necessary – are the best way of resolving that problem.
A PV solar power system, for example, is unable to supply power at night and even during the day production levels can change suddenly when clouds are present, causing potential imbalances in the network. In order to compensate for these fluctuations, conventional or more controllable renewable power stations, such as geothermal and hydropower plants, intervene.
According to Enel Green Power's Head of Innovation Scouting & Selection Fabrizio Bizzarri, storage systems play an key role in this situation, by 'enabling the adjustment of production according to the needs of the network without causing any repercussions. This means that a portion of the network can function autonomously at any time of day without having to resort to conventional power plants'.
There are several types of storage systems. Thermal storage uses the energy radiated by the sun to mitigate against sudden variations in power production brought about by the weather or day/night alterations. Electrochemical storage devices meanwhile require batteries, a battery management system, a DC/AC power conversion system, transformers, an electromechanical device to connect to the network and an intelligent energy management system. Pumped storage systems pump water in a reservoir located at the bottom of a hydropower station upstream to the tank when necessary, activating a new generation cycle.
Enel Green Power is completing the facility aimed at testing its first electrochemical storage system outside Italy, in the Chilean region of Antofagasta. Isolated mining village Ollague will be supplied with energy supplied by PV solar and small wind power, and the supply will be made steadier through the storage system. 'The diesel group that previously supplied the area will only be activated for a few hours at most during particular winter days, or in case of emergency, explained EGP's Luigi Lanuzza from Innovation Scouting & Selection. 'The site is ideal for testing because at an altitude of 3,700 metres plants are placed under severe environmental stress.'