30.95 Billion Cubic Meters Underground: Is Ukraine’s Gas Storage Really “Europe’s Largest”?

Ukraine stores natural gas for winter heating in underground facilities during the summer. These facilities are operated by Ukrtransgaz (Укртрансгаз), a joint-stock company whose sole shareholder is the state-owned Naftogaz (Нафтогаз України). The company’s website lists 12 underground storage facilities with a total capacity of 30.95 billion cubic meters.

Naftogaz describes this storage as “the largest in Europe.” Against what does this hold true? This article compares the figures with a list published by a European gas infrastructure operators’ association, and also looks, using publications and legal texts as of September 2026, at the rules for the “customs warehouse” arrangement under which foreign companies store gas, and the target for the winter of 2026. The halt in purchases from Russia and the course of domestic production and imports are covered in our article on gas procurement.

12 Facilities, 30.95 Billion Cubic Meters

Ukrtransgaz’s website (in a version archived in May 2026) describes the company as “the operator of Ukraine’s underground gas storage facilities” and lists 12 underground storage facilities with a total capacity of 30.95 billion cubic meters. It also states that the business of storing natural gas is licensed and regulated by the National Energy and Utilities Regulatory Commission (NEURC).

Naftogaz, the parent company, also gives a total capacity of 30.95 billion cubic meters in its company information. Its description of the storage business unit divides Ukrtransgaz’s facilities into “11 gas storage facilities located in mainland Ukraine” and “another underground storage facility located in the temporarily occupied territory of Luhansk Region.”

Capacity and the Amount Actually Stored Are Different Figures

30.95 billion cubic meters is the maximum quantity the storage facilities can hold. Naftogaz’s English-language description gives this figure as the total “active capacity” (the volume of gas that can be injected and withdrawn), stating it is “over 30 bcm.” The amount of gas actually in the facilities at any given time, on the other hand, changes greatly with the annual injection and winter withdrawal cycle.

As we will see in a later section, the government’s target for the amount to be stored by the start of the 2026–2027 heating season was 14.6 billion cubic meters. Compared with the total capacity, that is a little under half (approx. 47%). Whether the Luhansk facility is included in the total-capacity figure, and what that facility’s capacity is, cannot be determined from either company’s published figures.

“Europe’s Largest”: Compared to What?

Naftogaz describes Ukraine’s storage facilities as “the largest storage facilities in Europe and the third largest in the world.” A list that can be used for comparison is “AGSI,” published by Gas Infrastructure Europe (GIE), an association of European gas infrastructure operators. It gives, by country and by operator, the quantity of gas that can be stored (working gas capacity) in units of energy (terawatt-hours).

By country total, Ukraine’s capacity is the largest in this list, amounting to nearly 30% of the combined total of EU member states. By operator, too, Ukrtransgaz (321.1 TWh) exceeds the next largest, Italy’s Snam Stoccaggio (199.6 TWh) and France’s Storengy (90.0 TWh).

Some Countries Are Not Included in the Comparison

However, AGSI lists only facilities in EU member states, the UK, Ukraine, and Serbia. Russia, Belarus, Turkey, and others are not in the list. In this article, “Europe’s largest” means only that it holds true, by country and by company, within the scope of this list. “Third largest in the world” is Naftogaz’s own description, and this article has not verified it.

AGSI also lists the amount of gas held in Ukraine’s facilities. On September 25, 2026, the figure was 115.7 TWh, or 36% of capacity. Because this figure may not be counted the same way as the government’s announcement discussed in the next section (14.6 billion cubic meters as of August 28), this article uses AGSI’s data only for comparing capacity.

The “Customs Warehouse” Used by Foreign Companies

Foreign companies, as well as domestic ones, store gas in Ukraine’s storage facilities. The mechanism for this is a procedure under the Customs Code called the “customs warehouse” (mytnyi sklad). Article 121 of the Customs Code defines this procedure as follows.

A customs warehouse is a customs regime under which foreign or Ukrainian goods are stored under customs control, with conditional full exemption from taxation by customs payments and without the application of non-tariff regulation measures for foreign economic activity.

Customs Code of Ukraine, Article 121(1) (version as of September 17, 2026; translated from the Ukrainian original)

In other words: a customs warehouse lets Ukrainian or foreign goods be held under customs supervision, with a conditional, full exemption from customs duties and without non-tariff trade-regulation measures applying, for as long as they remain there.

The use of this procedure for natural gas was established by Ministry of Finance Order No. 292 of February 27, 2017. The order states that customs clearance of natural gas brought into the country for storage in these facilities is “carried out under the customs warehouse procedure,” and provides that “natural gas with different customs statuses may be stored simultaneously in the storage facilities.” The order was published in the official gazette on April 4, 2017, and took effect that day.

In an announcement of March 18, 2024, Naftogaz stated that foreign companies had entrusted 2.5 billion cubic meters of gas to storage in 2023, and Ukrtransgaz’s CEO stated that “more than 160 foreign energy companies from 32 countries around the world use store gas in ‘customs warehouse’ mode.” Both are the company’s own account.

Old Rule, Current Rule: From 1,095 Days to “Unlimited”

The period goods may be kept in a customs warehouse changed with an amendment to the law. Article 125 of the Customs Code, as it stood on January 1, 2025, provided that “the storage period under the customs warehouse procedure may not exceed 1,095 days from the day the goods are placed under this procedure.” This is the rule Naftogaz’s 2024 announcement refers to when it mentions “1,095 days.”

Law No. 3926-IX of August 22, 2024, rewrote Article 125. As of September 2026, the text states that “the storage period under the customs warehouse procedure is not limited,” with the sole exception of goods that could pose a danger to the environment or to human, animal, or plant health if stored for a long time. This law took effect six months after the day following its promulgation (April 2025).

The Target and Results for Winter 2026

What the government sets is not how much to inject during summer, but a target for how much should remain at the start of the heating season. According to the Interfax-Ukraine news agency, First Deputy Prime Minister and Minister of Energy Denys Shmyhal announced on April 9, 2026, a plan to have 14.6 billion cubic meters in underground storage by the start of the 2026–2027 heating season. Drawing on past winters’ experience, 13.2 billion cubic meters was set as the “critically necessary minimum.”

On August 28, 2026, the Ministry of Energy announced that the storage facilities now held 14.6 billion cubic meters of gas, saying the target had been reached a month ahead of schedule. These are government announcements, not figures confirmed by an independent body. The rules on when district heating begins are covered in our article on district heating.

Attacks and the Gas Facilities

Naftogaz has announced that since Russia’s full-scale invasion, its group’s gas facilities have continued to come under Russian attack. The number of attacks, and how the shortfall in domestic production has been made up through imports, are set out in our article on gas procurement.