New technologies for long-duration energy storage

Long-duration energy storage technologies are emerging as a crucial solution for enhancing flexibility in European power grids, a new report by Eurelectric and AFRY reveals. The study suggests that every gigawatt of long-duration storage capacity could yield annual savings of €150 to €250 million in variable operating costs. Such systems promise to significantly reduce the curtailment of renewable energy production, alleviate grid congestion, and contribute to a more reliable, decarbonized electricity system.

The increasing penetration of variable renewable sources like solar and wind power creates periods of surplus electricity, particularly in spring and summer. Conversely, winter demand often peaks when renewable generation may be lower. While pumped hydro storage has historically been Europe's primary solution for longer-term flexibility needs, the report highlights the growing potential of newer technologies. These include iron-air batteries, compressed air energy storage (CAES), and liquefied air energy storage (LAES), which offer the advantage of providing grid regulation for periods exceeding eight hours.

The economic viability of these storage solutions varies across European markets. In Germany and the United Kingdom, where wind power is a major contributor, technologies capable of storing energy for over 24 hours could become commercially attractive after 2040. Spain and Portugal, with their significant solar capacity, show particular promise for technologies offering eight to twelve hours of storage. However, in some markets, such as Finland, existing pumped hydro capacity and lower price volatility may limit revenue opportunities for new storage projects.

A key benefit of long-duration storage is its potential to mitigate the curtailment of renewable energy. This is especially relevant in regions where energy production and consumption are geographically separated, such as the north-south divide in Germany for wind power. Long-duration storage could absorb excess electricity during grid congestion and release it later when renewable generation is low. The report estimates that each megawatt of installed long-duration storage capacity could prevent approximately 2.2 to 4.5 megawatt-hours of renewable energy curtailment annually, with the most significant impacts observed in Spain and Portugal. Despite these advancements, investment hurdles remain.