Where are the gas reserves in the European Union

Potential to disrupt supply to the European Union (EU) gas from Russia arouses interest in can find alternativesand about how we can reduce consumption and storing the hydrocarbons in anticipation of supply problems.

For Mariano March Carpio

• Natural gas can be stored on a large scale in two ways:
• On the surface, conveniently manage the inputs and outputs of liquefied natural gas or LNG plants.

In the subsoil, inject the hydrocarbon under pressure and then remove it at will. This last option, very popular, and which this article focuses on, goes through the development of an underground storage infrastructure that aims to maintain minimal security stocks, also known as strategic reserves.

Minimum security stockTo ensure that these stocks are kept to a minimum, not only natural gas, but also petroleum products and liquefied petroleum gas (propane and butane), Spain has a mixed security of supply system. Obligations are divided between the Strategic Reserves of the Petroleum Products Corporation (SYSTEM

) and the oil and gas industry.

Functions are assigned to CORES to control compliance with the obligation to hold minimum stocks of securities. But in addition, as a differential activity for other similar European entities, its mission is also to guarantee adequate diversification of natural gas supplies to Spain, controlling that supplies from the same country of origin do not exceed 50% of the total.

The minimum security stocks are necessary to adjust supply to demand and to deal with peak consumption due to seasonal variations (summer-winter) or extreme weather events of a specific nature (floods, hurricanes, heat, or cold waves). events such as supply disruptions due to commercial, diplomatic or even war conflicts (as in the case of the Ukraine war).

Types of underground natural gas storage

1. There are three main types of underground gas storage. Each has its own physical and economic characteristics, which govern its suitability. The two most important characteristics of an underground storage facility are its capacity to retain natural gas for future use and the rate at which stored gas stocks can be extracted.

Old oil or gas fields already depleted

Many underground gas depots use commercially depleted natural gas or oil fields located near consumption centers. This type of storage is common in countries or regions that are, or have been, hydrocarbon producers, because of its availability and because existing wells and infrastructure can be used to convert a production area into a warehouse. These types of underground warehouses are usually the largest. Two examples in Spain are storage Seagull (Vizcaya) and Serrablo

2. (Huesca).

Excavation of caves into geological salt formations

The vast majority of storage facilities were built in salt caverns or caves in geological structures such as diapers or salt domes.

The construction of these caves, which are artificially created by dissolving salt by injecting hot water, is usually more expensive than the activities required to convert reduced oil and gas fields into storage.

3. However, salt caverns allow extraction operations of faster natural gas injection, which fully or partially compensates for this difference in costs.

deep saline aquifers

In some areas, natural saline aquifers have become underground gas stores. An aquifer is suitable for gas storage if the porous and permeable rock formation that holds the water is located under an impermeable rock that seals the previous one, preventing the escape of water and the injection of gas. Although the geology of aquifers is similar to the geology of the depleted oil or gas fields, their use as gas storage allows less flexibility in injection and extraction. An example of such storage is in Spain Yela is

(Guadalajara).

Worldwide and EU warehouses The first underground storage facility was opened in the United States in 1915. ByCáilteaz

at the end of 2018 there were already 662 scattered worldwide, with a total operational storage capacity of 421 billion cubic meters. Ias far as the EU is concerned , some details

• interesting are the following:
• Germany has about 63 storage facilities with a total capacity of about 22 billion cubic meters.
• Italy has about 14 with a total capacity of about 17 billion cubic meters.
• The Netherlands has 9 infrastructures (5 of them in salt caves) with a total storage capacity of about 13 billion cubic meters.
• France has about 23 warehouses (most of them in deep saline aquifers) with a total capacity of about 12 billion cubic meters.

Spain has 4 operational storage facilities, with a total capacity of 3 billion cubic meters. The biggest of them is Gaviota.

How many consumption days do they cover?According to Repsol data ( made offrom a variety of sources

) in total, the EU’s underground natural gas storage capacity is around 95 billion cubic meters, spread over about 160 facilities in 18 countries. 73 countries of the EU’s total capacity are concentrated in five countries: Germany, Italy, France, the Netherlands and Austria.

EU storage capacity averages 99 days of gas consumption, with large differences between countries depending on their storage capacity and consumption. Thus, Austrian storage capacity covers almost its annual consumption, while in Germany it would be less than 3 months and in Spain 34 days).

What level of ability do they have?

Demand for gas in Europe is highly seasonal and stock management is needed to reconcile the winter-summer divergence, to meet supply. In this sense, in view of possible disruption of gas supply from Russia, it should be remembered, according to Repsol’s own data (prepared from different data).fuentes

) European gas storage ended the winter season 2021/2022 at 26% of its capacity, below the historical average.

The EU forced member states to fill their gas storage to 80% of their capacity by 1 November 2022 (a percentage that should rise to 90% in subsequent years) as a measure to increase security of supply. To achieve this, Europe would have to import more than 50 billion cubic meters from April to November.

38% of their capacity is currently occupied by European storage facilities (in Spain this percentage is more than 60%), so a maximum and continuous supply of LNG would be required this summer, as well as the gas they receive through a pipeline (including Russian). , meet the proposed EU requirement of 80% by the beginning of November.

Not all European countries will be able to meet this requirement. Therefore, on 11 May, a new proposal was discussed which could limit gas storage obligations to a certain extent based on annual gas demand over the past five years, which would bring relief to countries with large storage capacity.

Emeritus Professor of Stratigraphy and Historical Geology, University of Barcelona.