Germany is developing both salt-based thermal energy storage and air-based energy storage technologies.
The salt-based systems use molten salt to store heat, which can then be used for heating or electricity generation. Air-based systems, like those developed by Augwind Energy, compress air and store it, often in underground salt caverns, for later use in power generation. These technologies aim to provide long-duration, large-scale energy storage to support the transition to renewable energy sources.
🌬️ Germany to Host World’s First Commercial-Scale AirBattery
Augwind’s Compressed Air Storage System Aims to Solve Renewable Energy’s Biggest Challenge
July 2025 — Germany will become home to the world’s first commercial-scale AirBattery, a long-duration energy storage system developed by Israeli company Augwind Energy. The facility will use Hydraulic Compressed Air Energy Storage (CAES) technology to store excess renewable electricity by compressing air into underground salt caverns, then releasing it to generate power when needed.
‘Key Features:
- 🧂 Storage Medium: Mined salt caverns, which are abundant in Germany and geologically ideal for high-pressure air storage.
- ⚡ Capacity: Each cavern can store 3–8 GWh of energy — enough to power tens of thousands of homes for days or even weeks.
- 🔁 Efficiency: Demonstrated 47% round-trip efficiency in pilot tests; commercial systems expected to exceed 60%.
- 🌍 Environmental Impact: Uses local materials, avoids lithium or rare earths, and has minimal hardware degradation over a 40-year lifespan.
- 🕰️ Commissioning: Expected between 2027 and 2028.
Why It Matters:
The AirBattery is designed to address “Dunkelflautes” — prolonged periods of low wind and solar output that challenge grid stability in Europe. Unlike lithium-ion batteries, which typically store energy for only a few hours, the AirBattery can store energy for weeks or even months, making it a potential game-changer for renewable energy integration and grid resilience.
“This is more than a project; it’s a milestone for achieving net zero,” said Or Yogev, CEO of Augwind.
Germany’s vast network of over 400 salt caverns offers a total theoretical storage potential of 330 TWh, positioning the country as a leader in scalable, long-duration energy storage.
Salt-Based Thermal Energy Storage:
- Mechanism:These systems heat a molten salt mixture (often a combination of sodium and potassium nitrates) to high temperatures (over 1,000°C) using excess electricity, usually from renewable sources.
- Storage:The heated salt is stored in insulated tanks, where it can retain heat for weeks or even months with minimal loss.
- Discharge:When energy is needed, the stored heat is transferred to a working fluid (like air or oil) to generate steam or provide direct heat.
- Advantages:They offer long-duration storage, can be scaled up, and use readily available materials, minimizing environmental impact.
Air-Based Energy Storage (Compressed Air Energy Storage – CAES):
- Mechanism:During periods of low energy demand, electricity is used to compress air and store it in underground salt caverns.
- Discharge:When energy is needed, the compressed air is released, mixed with fuel (like natural gas), and used to drive a turbine for electricity generation.
- Advantages:Can provide large-scale, long-duration storage, and the Huntorf plant in Germany has been operating since 1978.
- Other Applications:Augwind Energy is developing a technology that uses salt caverns for direct storage of compressed air, without the need for combustion, potentially reducing reliance on fossil fuels.
Key Benefits for Energy Transition:
- Long-duration storage:Both salt-based thermal and air-based systems can store energy for extended periods, addressing the intermittency of renewable energy sources like solar and wind.
- Grid stability:These technologies can help stabilize the electricity grid by providing a reliable source of backup power when renewable sources are unavailable.
- Decarbonization:By enabling the use of more renewable energy, these technologies contribute to reducing carbon emissions and mitigating climate change.
- Reduced reliance on fossil fuels:These systems can potentially replace or reduce the need for fossil fuel-based power plants for both electricity generation and industrial heating.