The energy transition needs powerful allies along its path. The decarbonization process calls for renewable power to boost its output and energy storage solutions respond precisely to this need, allowing renewables to overcome their weak spots - intermittent and non-programmable by nature - by unleashing their full potential, adjusting their energy output to match the real-time needs of the network grid. Thanks to storage systems, energy can be stockpiled during periods of low demand to be subsequently released when demand is at its peak. Moreover, these systems can support the grid’s stability thanks to their extreme readiness in responding to frequency oscillations. As a whole, the energy system becomes more flexible, sustainable and smarter. Research on storage systems is beneficial for all The 2019 Nobel prize in chemistry awarded to the creators of the Li-ion battery - John B. Goodenough, M. Stanley Whittingham, and Akira Yoshino – is testament to the enormous contribution this invention has provided to our daily lives: their applications encompass every technological environment, from laptops to smartphones and EVs, as they laid the groundwork for a wireless and carbon-free society that will ultimately benefit the environment. Our commitment to R&D allowed energy storage systems to perform a quantum leap in innovation over just 10 years. Back in 2010 Enel pioneered its first tests near Livorno, as part of the Pisa Research Centre, and research is still going strong to this day. As renewable power stations gain a larger market share, so are systems based on Li-ion batteries with e-mobility acting as its main driver for development. Their wide market availability makes them an economically feasible solution that nonetheless has still some critical issues to tackle. Starting with the sourcing of raw materials like cobalt, safety issues that must be efficiently managed and lastly, the development of reuse and recycling processes that curtail their ecological footprint. Flow batteries are standing out as an emerging solution. Engineered from more widely available and less hazardous raw materials, these batteries also stand out for the absolutely negligible levels of degradation from their usage. Thanks to their distinctive technology, stored energy and the power output aren’t intrinsically connected, while this product spec makes them particularly suitable for storage systems connected to renewable power stations. Together with battery systems, other energy storage solutions are currently being closely scrutinized like Liquid Air Energy Storage (LAES) and Gravity Storage, which is based on cranes that lift or lower weights depending on the need to stockpile or dispense energy. A solution in the making, coupling sustainability and circular economy Storage is undergoing a transition, as its usage is to be regulated by a gradual and case-specific approach, guaranteeing the safety, sustainability and economic soundness of the whole system. Basically, it all boils down to the end-of-life management that will need for transparent reuse and recycling processes to be put in place. This is the reason that prompted us to define specific sustainability indicators that drive the entire supply chain in adopting a “design-to-recycle” approach for their products. Moreover, we’re currently examining the feasibility of integrating former EV batteries in renewable power plants to provide storage services to the power grid while building the virtuous process also known as the circular economy. Along these lines of development did the “Second Life Melilla” come to life, as it was selected by the World Economic Forum (WEF) as a member initiative. The system will support the grid’s stability by harnessing power from former Nissan Leaf battery packs. At the same time, we’re considering possible “green” engineering solutions to define future storage systems, driven by a solid commitment and partnerships with some of the leading suppliers in the business. Among the latest cutting-edge operations we’ll test on our power stations is a thermal storage system developed by Brenmiller - an Israeli energy startup - and designed to stockpile high-temperature energy by using crushed rocks as a means to conserve energy in the form of extreme heat. Furthermore, two long-term storage systems - one based on a flux battery and the other on solid-state Lithium batteries - are being integrated in a newly built solar park in the Balearic island of Mallorca. This trio of innovative solutions is the backdrop to our Innovation Team as it helps suppliers in adapting as much as possible their infrastructure to the specific needs entailed by the energy transition, while setting the stage for widespread use of these technologies to improve Enel’s future competitiveness.