Long-duration energy storage is starting to move beyond pilot-stage discussions and into real deployment. In 2025, global installations passed 15 GWh, marking a 49% increase year on year. That is a notable step for a segment that still accounts for a relatively small share of the broader storage market, where lithium-ion continues to dominate shorter-duration applications. According to Wood Mackenzie, compressed air, thermal storage and vanadium redox flow batteries made up most of the new long-duration deployments last year, with China leading activity thanks to strong policy backing and industrial planning.
Even so, the picture is far from simple. The growth is real, but so are the commercial pressures around it. Funding has tightened, investors have become more selective, and long-duration technologies are still competing with cheaper and better-established battery systems in the four-to-eight-hour range. The result is a market that is clearly advancing, but not yet moving without friction.
At Power Loop, we see this as more than a storage headline. It points to a broader shift in how energy infrastructure is being valued at a time when digital demand is accelerating.
Why the data center sector should pay attention?
For data centers, power is never just a utility input. It shapes resilience, scalability and long-term viability. Facilities built for cloud workloads, enterprise continuity or AI applications are expected to operate without interruption, even when the wider energy system is under pressure. That puts growing focus on how electricity is produced, delivered and balanced throughout the day.
This is where long-duration storage enters the conversation in a more practical way. When renewable output drops, storage can help cover part of the gap. When generation exceeds immediate demand, it can preserve that energy for later use. And when grid conditions become more volatile, it can help smooth the pressure rather than leaving operators fully exposed to short-term swings. For digital infrastructure, that does not eliminate every risk, but it does improve the conditions around reliability.
The issue is becoming more pressing because electricity demand from digital infrastructure is rising fast. The International Energy Agency expects global data-center electricity use to reach around 945 TWh by 2030 in its base-case scenario, roughly double current levels. Europe is also expected to see a sharp increase, with demand rising by more than 45 TWh by the end of the decade. AI is one of the main reasons. As compute density rises and more accelerated workloads come online, data centers are placing heavier and more concentrated demands on power systems, often in very specific locations rather than across the grid as a whole.
That changes the development equation. In many markets, the challenge is no longer finding theoretical capacity on paper. It is finding locations where infrastructure can realistically support sustained, high-intensity electricity demand over time. Storage is not a cure-all, but it is becoming one of the tools that can make those systems more flexible and better prepared for what is coming next.
More renewables only work if the system can use them well
There is another reason this matters. Renewable energy is expanding across Europe, but variable generation does not always line up neatly with real consumption patterns. Wind and solar may be abundant during one part of the day and insufficient during another. That mismatch is manageable up to a point, but it becomes harder to ignore as clean generation takes up a larger share of the mix.
Long-duration storage helps make renewable power more usable, not simply more available. It gives the system more room to shift clean electricity into hours when demand is still there but generation has fallen away. For data centers, that can make a meaningful difference. It improves the chances of running more digital capacity on lower-carbon electricity without relying entirely on perfect real-time alignment between supply and demand.
For operators trying to expand while also meeting decarbonisation goals, this is becoming a practical concern rather than a distant one. The question is no longer whether renewable electricity is part of the future. It is how to build an infrastructure model that can rely on more of it without sacrificing operational stability.
Europe is starting to respond with capital and policy
The policy backdrop is also shifting. On 10 March 2026, the European Commission adopted its Clean Energy Investment Strategy, putting fresh emphasis on the scale of capital required for the energy transition. The figures are substantial: annual clean-energy investment needs are estimated at €660 billion through 2030, rising to €695 billion per year between 2031 and 2040.
That matters because it confirms something the market already knows. Europe’s transition will not be delivered by generation targets alone. It will depend on whether grids, storage, transmission assets and enabling infrastructure are financed quickly enough to keep pace with demand. The Commission has made clear that public budgets will not be sufficient on their own, which is why a greater role is now expected from private capital and institutions such as the European Investment Bank. The EIB is set to support this effort with more than €75 billion in financing over the next three years.
For the data-center sector, this is more than background policy. It suggests that energy flexibility, network reinforcement and system resilience are moving higher up the European investment agenda. That creates a more relevant framework for developers and operators whose projects depend on timely access to stable power.
What this means for site selection and digital infrastructure planning?
As energy and digital infrastructure become more closely linked, the value of a site is increasingly shaped by what stands behind the meter. Land, permits and fiber still matter, but they are no longer enough on their own. Investors and operators are looking more carefully at the quality of the surrounding power environment: how scalable it is, how resilient it is likely to be over time, and how well it can support future growth in a lower-carbon system.
That has direct implications for data-center development across Europe, including in Central and Eastern Europe. Markets that can combine strong connectivity with credible access to power and a realistic pathway for grid support will have a stronger case when competing for hyperscale, enterprise and AI-led investment. In that sense, long-duration storage fits into a wider story. It is part of the infrastructure layer that can help make strategic locations more investable in the years ahead.
For countries like Bulgaria, where the conversation around digital infrastructure is increasingly tied to power availability, transmission potential and renewable integration, these shifts are especially relevant. The more energy systems are expected to deliver flexibility as well as volume, the more important infrastructure readiness becomes.
The growth story is real, but the market is still under pressure
That said, this is not a mature or comfortable market yet. Wood Mackenzie describes long-duration storage as a segment caught in a strategic squeeze. Lithium-ion batteries remain more competitive in the commercially important medium-duration range, and many long-duration technologies still lack the pricing structures and demand visibility needed for large-scale expansion.
The financing numbers underline that reality. Global funding for long-duration energy storage declined by 30% year on year in 2025, while venture capital investment fell by 72%. Those figures do not cancel out the progress in deployments, but they do show that momentum alone is not enough. The sector still needs stronger commercial signals and more supportive investment conditions if it is to scale consistently.
That is worth keeping in mind when looking at the headline growth. The direction is promising, but the route remains uneven.
A bigger infrastructure story is taking shape
Even so, the broader trend should not be underestimated. Power demand is rising, AI is accelerating the pace of digital expansion, and Europe is trying to build an energy system that is both cleaner and more resilient. Those three shifts are happening at the same time, and they are starting to reinforce each other.
In that environment, the role of energy storage becomes harder to treat as a niche topic. For data centers, the conversation is already moving beyond simple access to megawatts. What matters more now is the quality of that power environment: whether it can support continuous operations, whether it can absorb more renewable generation, and whether it can scale without creating new bottlenecks.
That is why long-duration energy storage deserves closer attention. It may still represent a modest share of the market today, but its relevance is growing for exactly the kinds of systems that Europe now needs to build. On the surface, this is a clean-energy story. Underneath it, it is also a story about the next generation of digital infrastructure.
