An underground gas store in southwestern Poland has become a larger buffer against seasonal demand and supply disruptions. ORLEN says its newly completed Wierzchowice expansion increases the site’s working capacity from 1.3 to 2.1 billion cubic metres, raising Poland’s total storage capacity by roughly a quarter. But more space on paper is not the same as gas already in storage or new equipment fully cleared for operation. The distinction matters for understanding how much security the project can offer.
What ORLEN completed at Wierzchowice
Polish energy company ORLEN announced on 4 November 2026 that construction work on the expansion of its Wierzchowice underground gas-storage facility in Lower Silesia had been completed. The project increased the site’s stated working-gas capacity from 1.3 billion to 2.1 billion cubic metres (bcm), adding 800 million cubic metres. ORLEN describes Wierzchowice as Poland’s largest underground natural-gas store.
The increase at one facility is substantial: 0.8 bcm is about 62% of the original 1.3 bcm capacity. At the national level, Poland’s Ministry of Energy says total working-storage capacity is moving from approximately 3.3 bcm to 4.1 bcm, an increase of roughly one quarter. These are storage-capacity figures, not volumes of gas already injected into the ground.
Sources: ORLEN completes expansion of Wierzchowice Underground Gas Storage Facility · Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany · Orlen completes investment to add 25% to Poland's gas storage capacity
A completed construction project still has operating steps ahead
The distinction between construction and operation matters. The ministry’s 4 November statement says construction and installation work has finished, while commissioning of the new equipment and technical acceptance are still under way. Full use of the enlarged capacity also requires an amendment to the relevant licence from Poland’s energy regulator. The statement does not specify the date on which all 2.1 bcm will become available for routine commercial use.
That makes the headline increase a confirmed expansion milestone, but not proof that the entire additional capacity is already filled or fully accessible to the market. Likewise, the larger national capacity figure describes what the expanded system is designed to hold, not a freshly measured national inventory for 4 November.
Sources: Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany · ORLEN completes expansion of Wierzchowice Underground Gas Storage Facility
Where the PLN 580 million went
ORLEN put the cost at PLN 580 million, described in its English-language announcement as nearly PLN 600 million. The expansion included three new wells used for injecting and withdrawing gas, additional compressor units and improvements to the gas-dehydration installation. In a depleted-field storage site such as Wierzchowice, gas is held in geological formations previously used for production rather than in a new above-ground tank.
Those upgrades address two separate bottlenecks: how much gas can be stored and how quickly operators can move gas into or out of storage. The first sets the size of the buffer; the second affects how useful that buffer can be during rapid shifts in demand. A bigger reservoir alone would not automatically guarantee faster withdrawals on a cold day.
Sources: ORLEN completes expansion of Wierzchowice Underground Gas Storage Facility · Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany
The injection and withdrawal figures were project targets
When ORLEN launched the expansion in August 2023, it projected that daily injection capacity would rise by about one third, from 14.4 million to 19.2 million cubic metres, and daily withdrawal capacity by about 66%, from 14.4 million to 24 million cubic metres. Those figures came from the company’s original project announcement. They describe intended technical capability, not a reported measurement of actual gas flows in November 2026.
The 4 November 2026 completion announcement confirms that injection and withdrawal capability has been increased but does not repeat those daily figures or publish operational test results. Until commissioning, acceptance and updated operating information are available, the 2023 percentages should be treated as design targets rather than independently verified, currently deliverable rates.
Sources: ORLEN stawia na bezpieczeństwo – rusza największa inwestycja w krajowe magazyny gazu · ORLEN completes expansion of Wierzchowice Underground Gas Storage Facility · Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany
Why 4.1 bcm is still a limited national buffer
Reuters reported on 4 November that Poland consumes around 20 bcm of gas in a year. The new national storage-capacity figure of approximately 4.1 bcm is therefore equivalent to about one fifth of that annual volume in simple arithmetic. That comparison helps show the scale of the reserve, but it is not a forecast that storage could supply every user for a particular number of days.
Actual resilience depends on how much gas is in storage, the pace at which it can be withdrawn, seasonal demand and the availability of production, imports and pipeline connections. A storage site shifts gas across time; it does not create new gas. The expansion can increase flexibility without removing Poland’s need for ongoing supply.
Sources: Orlen completes investment to add 25% to Poland's gas storage capacity · Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany
A possible next expansion is not a new commitment
ORLEN says Wierzchowice was designed for a possible further expansion to 4.2 bcm at that site. That number is a longer-term potential capacity for Wierzchowice itself, not the present capacity of Poland’s entire storage network and not an additional project that ORLEN announced as approved or under construction on 4 November.
For now, the concrete development is the completed PLN 580 million construction project and its 800 million cubic metres of added designed storage space. The next verifiable steps are the remaining technical acceptance, the regulatory licence amendment and published operating-capacity data. Those milestones will establish when the additional space and associated flow capability can be used in practice.
Sources: ORLEN completes expansion of Wierzchowice Underground Gas Storage Facility · Polska zwiększa bezpieczeństwo gazowe. Największy w kraju magazyn w Wierzchowicach rozbudowany
