Supporting a gas storage site’s sustainable renovation in France

Thanks to the replacement of an old turbo-compressor with a new-generation electric compressor, operations at Storengy’s gas storage site in Gournay-sur-Aronde have become cleaner and more sustainable. Tractebel supported this ambitious project from start to finish.

Pictures: ©Storengy

In July 2025, the Electrocompression (EC4) project was completed with the industrial commissioning of the new electric compressor at the aquifer gas storage site operated by Storengy in Gournay-sur-Aronde, in the Oise region. It follows the gas-in operation in April, when natural gas was introduced into the system for the first time, enabling the start of gas operation testing. It marks the culmination of several years of studies, coordination, and construction work.

A sustainable project

Commissioned in 1976, the Gournay-sur-Aronde site is a key component of energy security in the Hauts-de-France region. It is the only Storengy site that stores B-gas, a low-energy natural gas imported from the Netherlands, in an underground aquifer. Its usable volume is equivalent to the annual consumption of the Lille/Roubaix/Tourcoing metropolitan area.

The EC4 project replaces an old turbo-compressor with a reversible electric compressor, capable of both compressing gas for storage and extracting it. It has been installed to meet the needs of the conversion phase from B gas to high-calorific H gas at very low flow rates, and to reinforce the reliability and durability of the compression equipment over time. This new equipment, which is more efficient and significantly less polluting, fully aligns with Storengy’s energy transition goals. It also strengthens the region’s energy supply security by facilitating seasonal gas storage.

Pictures: (1) piping, (2) electrocompressor, (3) Underground gas storage site  at Gournay-sur-Aronde (copyright Storengy)

Tractebel’s Role

Tractebel played a central role in this complex project with EPCM responsibilities (Engineering, Procurement, Construction, Management), providing:

• feasibility studies starting in 2018,
• basic design,
• detailed engineering,
• preparation of tender documents and support in drafting contracts for site works companies,
• checking execution studies,
• project management with complex schedule.

Our multidisciplinary teams – covering process, civil engineering, piping and mechanical equipment, electrical systems, and automation – successfully met the complex challenge of reusing as much existing equipment as possible (piping, valves, ventilation, etc.) while integrating the new components required for the project. Full commissioning of the electric compressor is scheduled for the end of June 2025.