TL;DR
Airengy and Hagag Europe are investing around €55 million to develop a 5 GWh compressed-air energy storage plant in Romania, using Airengy’s proprietary AirBattery technology. Construction is expected to begin in 2027, with commercial operation in early 2028.
Airengy and Hagag Europe are jointly developing a 5 GWh compressed-air energy storage (CAES) plant in Romania, with commercial operation targeted for early 2028. This project marks a significant milestone for Airengy’s proprietary AirBattery technology and aims to enhance grid stability and renewable integration in the region.
The project involves an investment of approximately €55 million ($63.6 million) and will utilize underground salt caverns to store compressed air. It is planned to be developed in two phases, with the first phase adding around 200 MWh of storage capacity at an estimated cost of €4.5 million. The total capacity aims to reach 25 MW of discharge power and up to 5 GWh of storage capacity.
Airengy will handle planning, design, construction, and operation of the plant, which will employ its AirBattery technology—a long-duration storage system that compresses air during periods of excess renewable generation and releases it to generate electricity. The technology uses only water and air, with no polluting materials or rare metals, and is designed for decades of low-wear operation.
Hagag Europe will secure usage rights for the salt caverns, many of which already have grid connections and nearby industrial facilities, facilitating project development. The project’s location in Romania was chosen partly due to favorable market conditions, including low costs and existing infrastructure.
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This development demonstrates a significant step forward in long-duration energy storage, providing a scalable solution to support renewable energy integration and grid stability in Europe. The use of underground salt caverns and environmentally friendly technology positions the project as a model for future storage initiatives. Its success could accelerate adoption of CAES systems across Europe, especially in markets with suitable geological formations.
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Romania’s Salt Caverns and Europe’s Energy Storage Landscape
Romania has a history of underground salt cavern gas storage, with several caverns already in use for natural gas. The country’s existing infrastructure and geological features make it an attractive location for large-scale compressed-air energy storage projects. Globally, CAES technology is gaining traction as a long-duration storage option that complements renewable energy sources, but commercial projects remain limited. Airengy’s AirBattery system is an innovative approach designed to operate efficiently over decades with minimal environmental impact.
Previous pilot projects in Israel have demonstrated AirBattery’s feasibility at smaller scales, paving the way for larger deployments like the one in Romania. The project aligns with broader European efforts to expand energy storage capacity and improve grid resilience amid increasing renewable penetration.
“The Romania project is a major vote of confidence in Airengy’s technology, which offers a climate-agnostic, low-cost storage solution for decarbonized grids.”
— an anonymous researcher
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Uncertainties About Project Timeline and Capacity
While construction is expected to start in 2027 and commercial operation in early 2028, specific project milestones and final capacity details remain subject to regulatory approvals, permitting, and technical development. The exact timeline for full capacity deployment and integration with local grids is still to be confirmed.
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Next Steps in Project Development and Deployment Timeline
Following finalization of permits and project planning, construction is anticipated to commence in 2027. The project will undergo phased development, with initial storage capacity of around 200 MWh and scaling toward the full 5 GWh target. Further updates are expected as project milestones are achieved, including grid connection agreements and operational testing.
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Key Questions
What is AirBattery technology?
AirBattery is a proprietary long-duration compressed-air energy storage system that uses underground salt caverns to store compressed air, which is then released to generate electricity via a hydraulic turbine, using only water and air with no polluting materials.
Why is Romania an attractive location for this project?
Romania offers existing salt caverns suitable for storage, established grid connections, and favorable cost and policy environments that support large-scale energy storage development.
When is the project expected to be operational?
Commercial operation is targeted for early 2028, with construction planned to begin in 2027.
How does this project support renewable energy integration?
The large-scale storage capacity will enable the grid to better balance renewable generation, store excess energy, and provide grid stability services.
What are the environmental impacts of AirBattery?
The system uses only water and air, with no polluting materials or rare metals, making it a low-impact, climate-agnostic solution for long-term energy storage.
Source: PV Magazine
