Cavern Facility in Etzel


Unique infrastructure

STORAG ETZEL had been entrusted in 1971 to build 33 caverns for the storage of oil and to operate the above-ground facilities on behalf of the Federal Government of Germany. In 1993, the company was privatized. In 2005, STORAG ETZEL took over the ownership of the cavern facility and subsequently expanded it to its present significance.

Advantages of the location

After thorough geological investigation the massive Etzel salt dome was selected in the early 1970s for the realization of the cavern project. The Etzel location was found ideal for cavern construction as there is a unique underground salt deposit. The mighty salt beds were formed some 250 million years ago and were later covered by sediments. In the course of the following geological development a mushroom-shaped structure, a so-called salt dome, was formed in the area of ​​Etzel.

A big advantage of the Etzel site is the proximity to the North Sea (Jade Bay) and the port infrastructure of Wilhelmshaven (e.g. the Niedersachsen Jetty and the NWO oil port). At NWO oil jetty crude oil is landed by tank vessels. At the Niedersachsen Jetty, seawater is withdrawn for the solution mining process and brine from the caverns is returned and disposed into the North Sea nearby. For the transfer of these fluids three company owned pipelines for sea water, brine and crude oil are operated between the Etzel site and Wilhelmshaven.

In Europe, there are very few cavern storages that show up similar favorable conditions for cavern construction compared to Etzel. Our tenants are European companies from the energy sector and stockpiling associations that take care of their national crude oil reserves.

STORAG ETZEL´s main operation site

The heart of the cavern facility is the main pumping station equipped with 16 powerful pumps. These pumps are used for the solution mining operation in order to dissolve the salt an create a cavity (cavern). During storage operation the pumps serve the purpose to pump crude oil into the cavern and displace the brine, and for withdrawal of the product, to pump in seawater to displace the oil. Oil filling for storage and withdrawal for further use are performed on customer demand.

The storage facility at Etzel also benefits from its ideal geographic position by being directly connected to the North West European oil and gas pipeline network, ensuring efficient transport and market-oriented flexibility.

Crude Oil Storage Capacity

STORAG ETZEL, with more than 10 million cubic meters of crude oil stored in 24 caverns in Etzel, is operating one of Europe's largest crude oil storage companies. The amount of oil stored underground in Etzel today would require 100 tanks on an area of ​​8 km² in a conventional surface tank farm.

The crude oil is used by oil storage associations of various European states as a national crisis stock. Crude oil is preferably stored underground in caverns and close to logistic hubs, where refineries can be supplied if required.

The Etzel site is connected to the tank farm of the Nord-West Oelleitung GmbH (NWO) in Wilhelmshaven. From there, the crude oil can be fed either via pipelines or seagoing vessels for processing.

The Etzel cavern facility does not only supports the supply security of Germany, but due to its excellent location and the existing infrastructure also further EU states - a prime example of functioning European cooperation.

Natural Gas Storage

Natural gas production and pipeline transport from the far-off gas fields are usually continuous and not suitable to supply on-demand. In Europe significantly more natural gas is needed in the winter half-year than in the summer half-year what makes interim storage necessary. With the help of underground storages seasonal and peak demand as well as supply fluctuations or even delivery interruptions can be compensated.

The operation of the gas caverns requires special surface gas facilities according to state-of-the-art, which directly fall under the responsibility of the tenants. Currently, four gas operator consortia have settled at the Etzel site and signed long lasting storage contracts: 

  • EGL: Etzel Gas-Lager (EGL) is a consortium of Uniper Energy Storage GmbH, Equinor Storage Deutschland GmbH and Total Etzel Gas-Lager GmbH. The gas plant has been operational since 1993. Equinor Storage Germany is the operator for the aboveground systems of the EGL and legally responsible according to the mining law, STORAG ​​ETZEL is technical service provider and plant manager of the EGL
  • EKB Storage: Etzel-Kavernenbetriebsgesellschaft mbH & Co. KG (EKB) is a joint venture of BP Europe SE, Ørsted and GAZPROM Germania
  • ESE: The ESE-Erdgasspeicher Etzel is a consortium of Uniper Storage GmbH, OMV Gas & Power GmbH, VNG - Verbundnetz Gas Aktiengesellschaft and Gas Union. The gas facility is operated by Uniper Storage GmbH
  • FSG Crystal: Friedeburger Speicherbetriebsgesellschaft mbH Crystal is a joint project of EnBW Energie Baden-Württemberg Etzel Speicher GmbH and Électricité de France (EdF) Gas Deutschland GmbH

The gas infrastructure at the location is excellently connected to four regional pipelines, the NETRA (entry and exit stopover), the Emden-Etzel Pipeline and the Bunde-Etzel Pipeline (BEP). The BEP was completed last in 2011 and connects the cavern facility over 60 km to the gas pipeline junction in Bunde / Oude Statenzijl links Etzel to the Dutch gas network.

Since 2007, the STORAG ​​ETZEL cavern facility has become one of the largest oil and gas storage facilities in Europe. Beyond the currently existing 75 caverns, further storage cavities within the Etzel salt dome can be created in total. There is an expansion potential up to 99 cavern locations. Today, a considerable portion of the total volume of all German crude oil and natural gas reserves is stored at Etzel.