The topic of energy storage is becoming increasingly relevant as decarbonization goals become more ambitious. The growing penetration of non-programmable renewable energy sources (NDRES) and the increasing electrification of transportation lead to a series of challenges related to the stability and flexibility of the electrical system, making it inevitable to resort to solutions capable of storing excess renewable energy for later use where and when it is needed.

This project focuses on the technological development of electrochemical and electrical storage systems (batteries and supercapacitors), chemical or power-to-gas storage (production, distribution, and storage of natural gas and hydrogen), and thermal storage (storing heat produced from renewable sources). The technological solutions developed here are focused on stationary storage, but some could also be applied to vehicle applications.

The document describes the main results achieved so far.

The development of innovative batteries has led to technological solutions capable of increasing the specific capacity of active materials (and therefore the energy density, which translates to lighter weight) and the number of charge and discharge cycles without losing specific capacity (and therefore extending useful life), also through the development of appropriate active control systems, which are additionally capable of adapting to 2nd life applications.

Life Cycle Assessment and Life Cycle Costing studies, carried out on the entire life cycle of electrochemical storage systems for stationary applications, have made it possible to measure the real environmental and economic impact of these technologies.

The power-to-gas solutions developed have resulted in the effective production of methane (and hydrogen), improving the conversion efficiency from NDRES to fuel. This fuel, once injected into the network, can be used in electric power generation systems but also in transportation: vehicles powered by bio-methane or bio-hydrogen. The project, through appropriate modeling activities, also achieved results in validating solutions for geological hydrogen storage in depleted natural gas reservoirs.

The thermal storage solutions studied and developed in this project can indirectly impact the electrical system. These aim to be combined with thermal renewable energy sources, such as solar thermal, to directly utilize the renewable source to produce heat and store it for long periods, in a primary energy-saving perspective, thereby relieving the electrical grid from this contribution to decarbonization. The modeling activities carried out have validated large-capacity thermal storage solutions in deep aquifers (ATES systems).