The topic of energy storage is gaining significant importance due to ambitious decarbonization goals. The increasing penetration of non-dispatchable renewable energy sources (NRRES) and the growing electrification of transportation present a series of challenges related to the stability and flexibility of the power system, making it inevitable to rely on solutions capable of storing excess renewable energy for later use where and when it is needed.

Project 1.2 focuses on the technological development of electrochemical and electrical storage systems (batteries and supercapacitors), chemical or power-to-gas systems (production, distribution, and storage of natural gas and hydrogen), and thermal storage (storing heat produced from renewable sources). The technological solutions developed in this project are primarily aimed at stationary storage, though some may also find applications in vehicles.

The document describes the main results achieved.

The development of innovative batteries has led to technological solutions that can increase the specific capacity of active materials (and thus the energy density, which translates to lighter weight) and the number of charge-discharge cycles without losing specific capacity (thereby extending the battery’s useful life), including through the development of appropriate active control systems, which can also adapt to second-life applications.

Life Cycle Assessment and Life Cycle Costing studies conducted 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 effectively generated methane (and hydrogen), improving the conversion efficiency from NRRES to fuel. This fuel, injected into the grid, can be used in power generation systems as well as in transportation, such as in bio-methane or bio-hydrogen vehicles. Through appropriate modeling activities, the project also achieved results in validating geological hydrogen storage solutions in depleted natural gas reservoirs.

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

Hydrogen deserves special attention. Scenario analyses were conducted, and appropriate guidance was provided to help institutions draft the national hydrogen strategy. Additionally, some technological solutions along the value chain were studied. In particular, the potential technical and economic applications of green hydrogen were analyzed in the integrated water system, biomass, and waste sectors. Finally, regulatory aspects regarding the interoperability of gas transport networks and regulations on the safety and explosion risks of hydrogen-containing equipment were addressed.