Storage Technologies Consolidating Renewables

Published on Wednesday, 25 March 2015

Over the last five years, about 150GW of PV and wind power plants have been installed in Europe, demonstrating the energy sector's commitment to work toward a more sustainable form of power generation.

The “non-programmability” of renewable sources, one of the factors that has prevented their large-scale deployment, is close to reaching a solution: the development of increasingly sophisticated mathematical models which can analyse an enormous quantity of data, can predict production within the following 24 hours, with an average forecast error that is equal to that of energy demand forecasts.

Nevertheless, in order for wind and PV plants to provide dispatch network services, production must be fully programmable. Today, such a scenario is becoming increasingly realistic, thanks to the development of new electric or electrochemical storage technologies, such as supercapacitors and large-scale batteries  – systems that also offer numerous services to customers in the distribution network.

Since 2010, Enel has been committed to the development of innovative storage systems, which it has tested in the Enel Experimental Area in Livorno. The research centre has analysed the characteristics and potential of 13 different technologies, by mapping the main product families that are being developed worldwide and launching large-scale projects. So far, storage systems with a total capacity of 21 MW have either been installed or are in the process of being implemented, subdivided into three lines of business: energy storage in the islands and in "off-grid" applications (those that are not connected to the network); integration with renewable energy plants; centralised storage systems integrated with the distribution network.

Enel has launched three projects to provide energy storage in isolated networks, such as islands or continental areas that are not connected to a national network. The first project was launched on the island of Ventotene, Italy, where a complex storage system was installed (with a 300 kilowatt, 600 kilowatt-hour lithium-ion battery), coupled with Diesel engines.

The second project, called STORE - Storage Technologies of Reliable Energy, was developed in the Canary Islands in Spain, in which three different storage technologies support the stability of the local network: 1MW/3MWh lithium batteries in Gran Canaria, a 0.5 MW/18 MWs inertial storage unit (a so-called "flywheel") in La Gomera, and a 4 MW/20 MWs ultracapacitor system in La Palma.

The third project in Ollague, in Northern Chile, combines innovation and sustainability, while using storage to supply power to a remote area that is not reached by the power grid. A renewable hybrid plant (based on wind and solar power) was manufactured and is supported by a 250 kW/520 kWh storage system in order to supply energy in case of intermittency.

Enel also launched ActiveRES into the grid, a project that sees the integration of storage systems with renewable energy plants. Three different experimental electrochemical storage systems are connected to the electrical grid (Primary Substation, medium and low-voltage grids), optimising the use of existing connections and renewable sources.

The Enel Group also participated in the European project, Grid4EU - Innovation for Energy Networks, as part of a consortium of companies and research institutions from 12 European countries. The Group is developing a demonstration project that uses storage to regulate voltage and increase the hosting capacity of secondary substations. In Isernia, Italy, Enel installed the first energy storage system on the distribution network, by integrating it into a smart grid that includes a charging station for electric vehicles, 50 kW of PV power and "home energy management" systems, enabled by Smart Info (also developed by Enel).

Among Enel's innovations are electrochemical accumulators to create the smart grid “ring” that will supply energy to the smart city exhibition site at Expo Milano 2015, of which the company is an Official Global partner.