Electricity Storage Systems
Today, especially when electricity generation units are from renewable sources, the possible occurrence of network stability problems due to the instability of these generators limits the diffusion of distributed generation.
Coupling electricity storage systems with electricity generators from renewable sources would temporally decouple the production and consumption of electricity, thus favoring greater diffusion of such power generation systems, which have production curves that are not easily predictable and that often do not coincide with the load curves.
The storage systems, which are used in distributed generation applications, can perform different tasks and should therefore be sized on the basis of the performance required. In fact, some applications require "power performance", that is systems capable of delivering high power for short periods (from fractions of a second to tens of seconds), while others require "energy performance", that is systems capable of supplying power autonomously for a few hours.
Among the various technologies of electricity accumulators applicable in distributed generation, one that has suitable features for different applications, by virtue of the high values of specific energy and power as well as the very rapid response times, is the technology of lithium-ion batteries.
In this context, the activities carried out by RSE concern the characterization of lithium batteries as well as the design of a storage system and the definition of a procedure for characterization of these batteries.
With regard to the Zebra batteries a control system has been developed for the optimal management of the simultaneous charging of several Zebra batteries within a storage system connected to the LV network.
Dynamic stress tests have been carried out on lithium and Zebra batteries to analyze the behavior of the storage systems used according to the typical procedures of transmission applications.
As regards electrochemical storage, a test station has been devised for the experimental characterization of sodium-sulfur and/or sodium-nickel-chloride mono-cells in order to analyze the behavior from a heat exchange point of view (as well as electrochemical).