IN Brief:
- European storage organisations have called for long-duration energy storage to be recognised as strategic energy infrastructure.
- The appeal focuses on policy planning, market design, investment frameworks, and deployment support for longer-duration flexibility.
- Europe’s power system requires storage that can operate beyond short-cycle balancing and intraday price response.
Energy Storage Europe, the Long Duration Energy Storage Council, and other storage organisations are urging the European Commission to recognise long-duration energy storage as a strategic pillar of Europe’s electrification and energy security agenda.
The joint call asks the Commission to integrate long-duration storage into future policy initiatives and support deployment through clearer planning, market, and investment frameworks. Higher renewable penetration, heavier electrification loads, and greater exposure to prolonged periods of low wind or solar output are changing the type of flexibility required across the European power system.
Short-duration lithium-ion batteries are already scaling quickly across several European markets. They are well suited to frequency response, intraday trading, peak shifting, and short-term renewable balancing. Longer-duration storage addresses a different operating requirement: sustained system stress, extended renewable lulls, congestion events, industrial demand peaks, and resilience needs that cannot be met by two-hour assets alone.
The technology mix is broad. Pumped hydro, compressed air, liquid air, thermal storage, flow batteries, hydrogen-based systems, and other electrochemical approaches can all contribute different durations, efficiencies, response characteristics, and siting requirements. Treating long-duration storage as a single technology would miss the operational differences between those assets, but leaving them outside mainstream market design risks underbuilding capacity the system will later require.
Many long-duration projects face high upfront capital costs, long development timelines, uncertain revenue stacking, and market structures that do not fully value duration. Capacity mechanisms, balancing markets, ancillary services, congestion relief, and renewable integration products have often been designed around shorter time horizons. As a result, longer-duration assets can provide system value that is difficult to convert into bankable revenue.
Europe’s storage market is already moving from individual battery announcements toward more formal procurement and system planning. Italy’s MACSE auction framework is targeting 16GWh of storage capacity for 2029 delivery under long-term contracts, giving developers clearer investment conditions while aligning storage with zonal system needs.
Long-duration storage raises a wider version of the same procurement challenge. A four-hour battery, pumped hydro scheme, thermal store, and hydrogen storage facility do not deliver identical services. Duration, response time, cycle frequency, location, efficiency, construction lead time, environmental profile, and connection requirements all influence the value each technology can provide.
Network planning is closely tied to that debate. More renewable generation does not remove the need for firm capacity during extended periods of low output, while grid constraints can prevent renewable power from reaching demand centres even when generation is available. Storage located in the right part of the system can reduce curtailment, defer reinforcement, support voltage management, and improve resilience, provided those locational benefits are recognised in planning and market rules.
Industrial electrification adds another layer of demand. Large users need predictable power availability and may require storage to manage process continuity, demand charges, and exposure to volatile prices. As more process heat, transport, and manufacturing loads move onto electricity, flexibility requirements will stretch across longer and more varied demand profiles.
Short-duration storage will remain an essential part of the system, especially for fast-response services and daily cycling. The storage mix required for a renewables-heavy system, however, will need assets that can operate across multiple durations and market conditions. Without clearer policy treatment, longer-duration projects risk remaining outside mainstream procurement until the operating need becomes harder to manage.
Energy Storage Europe’s work on long-duration energy storage deployment sets out the association’s recommendations for aligning planning, markets, and financing with long-term flexibility requirements.
