ACER recommends aligning Slovak gas transmission tariffs with EU rules

Today, ACER releases its report on the Slovak gas transmission tariffs directed at Eustream, Slovakia’s transmission system operator (TSO).

The report assesses the compliance of the proposed reference price methodology (RPM) with the requirements of the EU Network Code on Harmonised Transmission Tariff Structures (NC TAR).

What is the proposed tariff methodology?

The Slovak TSO proposes to:

• Change the current methodology to introduce new tariffs in the middle of the ongoing tariff period, which would result in a tariff increase of more than 70%. The TSO cites exceptional circumstances (a large drop in cross-system flows) as the reason for this change.
• Apply a uniform postage stamp reference price methodology with an ex-ante entry-exit split, covering the multi-year tariff period 2026-2027.
• Continue recovering transmission revenues through a mix of capacity-based charges (paid for reserving network capacity) and commodity-based charges (linked to the volume of gas transported).
• Adjust capacity tariffs at all entry and exit points (including domestic points) using benchmarking to lower tariffs and make them more competitive. Eustream proposes to use a wide set of European TSO tariffs, including those from Northwestern Europe, as a reference.
• Keep two commodity-based charges in place:
  • a flow-based charge paid in kind (meaning a portion of transported gas is normally used to cover the fee); and
  • a complementary revenue recovery charge, designed to help recover the costs of the Slovakia-Poland gas interconnector.

What are the key findings? 

After analysing the consultation document, ACER concludes that:

• The proposed methodology meets the EU requirement on non-discrimination.
• Compliance with the requirements on transparency, cost-reflectivity, avoidance of cross-subsidisation, volume risk and the prevention of cross-border trade distortions cannot be confirmed. This is mainly due to the proposed benchmarking adjustment, which does not meet NC TAR standards.
• The proposed commodity-based charges are also non-compliant. Specifically, the flow-based charge is adjusted by a discount for domestic flows, which is not allowed under EU rules.

What does ACER recommend? 

ACER recommends that the Slovak national regulator (ÚRSO), when adopting its final decision on the proposed methodology:

• Limit benchmarking adjustments to points with clearly identified competition between pipelines, so that tariffs reflect actual market conditions and remain predictable for network users.
• Implement measures to improve alignment with NC requirements, despite current challenges to full compliance.
• Phase out the non-compliant discount applied to the flow-based tariff.

See all ACER reports on national tariff consultation documents.