Why long duration energy storage will be the heart of Europe’s energy future

August 19, 2025

By Julia Souder, CEO, Long Duration Energy Storage Council

Over the past few weeks, I’ve had the opportunity to visit some of Europe’s most innovative long duration energy storage (LDES) developers. From Vienna to Kongsberg to Munich to Bathgate, I met with members of the LDES Council who are doing some of the most exciting work in energy storage today. 

Everywhere I went, one thing was crystal clear:

Long Duration Energy Storage isn’t theoretical. It’s operational.

These are not speculative technologies—they’re working systems, scaling to meet industrial, commercial, and grid needs today.

What Europe’s LDES momentum tells us 

Europe has played a major role in advancing renewable energy. 

Now it’s entering a new phase of infrastructure maturity. What struck me most is how many of our members are:

  • Scaling up manufacturing capacity
  • Rolling out more commercial deployments this year
  • Demonstrating real-world impact—cutting industrial fuel use, enabling 24/7 clean energy, and creating green baseload power

This is critical, because Europe’s 2030 climate and energy targets will require not just more wind and solar, but the flexibility to bridge days, weeks and months between supply and demand. LDES fills the missing piece, ensuring clean energy isn’t just produced, but delivered reliably across time and demand.


Diverse solutions, shared purpose

Every visit reinforced long duration energy storage is rising to meet a wide range of demands: from industrial heat to grid stability to clean power for remote or hard-to-electrify sectors. Given the complexity of Europe’s energy mix and industrial landscape, flexibility isn’t optional—it’s essential. Here’s what I saw:

  • In the UK, AWS is exploring how LDES can support data centers with grid flexibility and cost savings. CERES is developing electrochemical systems for clean power, hydrogen production, and long-duration storage at scale. Invinity is scaling up vanadium flow battery production for commercial and grid customers.
  • In Norway, TechnipFMC is transforming offshore infrastructure—integrating hydrogen, LDES, and hybrid systems to deliver flexible, zero-emission power, building on decades of oil and gas expertise and applying systems thinking to LDES.
  • In Germany, Kraftblock is helping industries cut fossil fuel use with thermal storage. VoltStorage is preparing its first iron flow battery deployment, offering green baseload power for facilities that can’t run on 4-hour lithium-ion alone. BASF is advancing sodium-sulfur battery technology, bringing heavyweight industrial R&D power to the long duration challenge. •
  • In Austria, CellCube is proving how flow batteries can be safe, long-lasting, and ready to deliver 7/24 renewables, with decades of experience behind them. •
  • In Sweden, we visited SENS to explore how combining solar, BESS, and underground pumped hydro can offer a flexible, site-specific approach to long duration storage.
  • This diversity is Europe’s strength. Each solution meets a different need — from heat to power to off-grid reliability. Collectively, these technologies are leveraging on delivering value across use cases.

It is becoming clearer to see LDES as a critical tool for strengthening system flexibility, reliability, and decarbonisation across the energy landscape. And if we want more of that, faster, policy needs to catch up.

Unlocking LDES through policy

Our technology is ready. The projects are live. But in too many cases, policy hasn’t caught up.

Europe doesn’t just need more renewables—it needs the flexibility to use them. Without long-duration storage, power systems stay exposed to volatility, fossil fuels, and missed decarbonisation targets.

Recent EU initiatives, like the Electricity Market Design reform, new flexibility requirements, and ongoing consultations on power-to-heat, show progress. But most frameworks are still built around short-duration batteries. That leaves out the long-duration systems already able to store power for 8+ 24, 48, even 100 hours—technologies critical for providing flexibility and reliability across both power and heat.

Member visits showed these longer-duration systems are already working—in industrial heat, data centers, offshore infrastructure, and beyond.

To scale them, policy needs to deliver:

  • Procurement frameworks rewarding duration, not just fast response, •
  • Market signals recognising LDES in grid services and resilience planning,
  • Updated definitions reflecting technologies already deployed—from thermal to flow to underground pumped hydro.

Until we align policy with the technologies already proving their value, Europe will keep leaving clean energy, and climate progress, on the table. LDES is ready to deliver; now policy must be ready to match it.

My personal take

My visits across Europe left me not only inspired, but also energised to push harder for change.

LDES companies are here. The demand is here. Now we need policy to rise to the need—with frameworks that reflect what’s already working on the ground.

At the LDES Council, we’ll keep working with our members, policymakers, and regulators to build a cleaner, more resilient energy system: One that runs when you need it, for as long as you need it.

Let’s make LDES the heart of Europe’s energy transition.

Media Contact:
Elis Rosenberg
erosenberg@ldescouncil.com