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Storage

We operate two underground natural gas storage facilities, at our Lussagnet (Landes – 40) and Izaute (Gers – 32) sites.

Strategic equipment

The two underground sites, at Lussagnet and Izaute, represent nearly one quarter of France’s underground natural gas Storage Capacity. They supply the whole of our network and part of the other French networks. Thanks to their geographic position, Lussagnet and Izaute are at a crossroads of south European gas exchanges.

Guarantee continuity of supply

Energy consumption is closely related to climatic variations, and changes significantly from pone period to another throughout the year. We enable our customers to exercise a strategic balancing role by adjusting the volumes of natural gas in storage. Natural gas is injected into storage during the summer, and then drawn off over the winter period to supply consumers. Storage therefore enables us to guarantee continuity of supply by fully topping up the amount of gas needed to cover user needs at any given moment.

Quality, safety, respect for the environment: proven expertise

Within the context of opening gas markets, the Lussagnet and Izaute storage facilities have all the characteristics required to meet natural gas suppliers’ flexibility requirements. The concept of continous improvement is central to the Teréga storage management system, wich is certified:

  • ISO 9001 for the quality of the gas odorisation operation, a guarantee of user safety;
  • ISO 14001 for its environmental management system across all our sites and activities;
  • ISO 50001 for its management of energy efficiency;
  • level 8 recognition within the international safety rating system (ISRS).

More than 50 years’ experience

The Lussagnet and Izaute underground storage facilities, located close together in geographic terms, were developed under different conditions. The Lussagnet site began operating in 1957, at the same time as the Lacq gas field came on stream, and was intended at that time to regulate the production of natural gas from the Lacq plant. Its capacity has been increased fourfold since it was created. The Izaute storage site, meanwhile, was brought into service at the start of the 1980s in response to increasing demand for gas. This continuing growth and the increase in exchanges resulting from the opening up of markets across Europe will continue to drive development of the Lussagnet and Izaute sites.

The underground sands of Lussagnet and Izaute

40 million years ago, Lussagnet and Izaute were on the coastline. Erosion of the Massif Central has formed the different geological strata to be found underground. The sands of one of these strata enclose an aquifer which extends under southwestern France, from the Pyrenees to the north of the Bordeaux region, and across to the foothills of the Massif Central. Over the years, the formation of the Pyrenees has caused folds to develop. The sandy layer resulting from two of these folds is now used for storage. Formed from molasse and clays more than 500 metres thick, this geological stratum forms a perfect seal. The storage at Lussagnet and Izaute is located between 500 and 900 metres below ground level.

Geological cutaway diagram showing storage

Geological cutaway diagram showing storage

Origin of stored gas

The natural gas stored at Lussagnet and Izaute is essentially brought by gas pipeline from the production sites in Norway and Russia, or via the Fos methane terminals and Midi Artery from Algeria and Nigeria.

Injection, draw-off, treatment

Natural gas is brought from the production sites or methane terminals to the storage facilities. During the summer, it is compressed and then injected through wells into the underground reservoir. It then displaces the water contained in the storage sand. In winter, to deal with increasing demand, the natural gas is drawn off through those same wells. The water displaced by injection then returns quite naturally to the space it occupied in the sand. Once at the surface and compressed, the gas is subjected to a range of treatments to meet the specifications of distribution circuits: dehydration, desulphurisation if necessary, decompression and odorisation.

Rigorous operation of installations

Before finding its way onto the grid, the natural gas is constantly being analysed. A number of criteria enable us to guarantee the constant quality of the product being delivered to the end customer. The Izaute storage is linked to Lussagnet by two pipelines 60 cm in diameter and approximately 10 km long.

Synergy between storage and the transport grid

The complementarity between our storage and gas transport activities offers Shippers greater flexibility in their daily management of flow allocations.

In particular, the precise management of storage capacities enables us to fulfil our public service obligations.

Key figures: the Lussagnet storage platform

  • 2 gas dehydration units
  • 4 triethylene glycol regeneration units, used to dehydrate gas
  • 2 desulphurisation units including active carbon reactors
  • 7 compressors with a total power of 30 MW
  • 1 analytical laboratory for constant gas quality monitoring
  • 1 commercial gas odorisation unit
  • 1 control room

Control room

Control room

Aerial view of Lussagnet

Aerial view of Lussagnet

Storage sales contacts

Sales contacts

Map of installations

Map of installations

List of Teréga territories operating in the 15 departments of the South West

EN Standard TEREGA : 0 559 133 400EN Urgence Gaz : 0 800 028 800

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