ACER tells Ireland to reclassify the Corrib Linkline before December
Serguey Asael Shinder2 min readACER has published its assessment of what Ireland's regulator, the CRU, proposes to charge for moving gas across the national network, measured against the EU network code on harmonised transmission tariff structures. The report is at https://www.acer.europa.eu/news/acer-finds-irish-gas-transmission-tariffs-largely-compliant-eu-rules-calls-clarity-corrib-linkline-service. The CRU has until 16 December 2026 to adopt its final decision.
What Ireland proposes is a forward-looking matrix method: the difference between tariffs at two network points reflects what it would cost to expand the pipe between them, not what it historically cost to build. Every exit point serving domestic consumption pays the same tariff, and a single tariff would apply to all future renewable gas production points wherever they connect. Revenue keeps coming from a mix of capacity charges on contracted capacity and commodity charges on volumes moved.
ACER's verdict is mostly favourable: the method meets the EU tests on cost-reflectivity, transparency, avoidance of cross-subsidisation, non-discrimination, volume risk and distortion of cross-border trade, and the flow-based charge criteria are met too. Two things are not settled.
The Corrib Linkline. The pipeline connecting the Corrib offshore field to the main Irish ring is recovered through its own tariff and treated much like a non-transmission service — without being formally classified as one. ACER wants the classification made explicit and the revenue and tariff structure described properly.
The forecasts. The capacity numbers underneath the methodology come from Ireland's 2024 Network Development Plan, which ACER says may not capture more recent shifts in demand. It asks for updated estimates, and for the methodology to be re-tested against the code if those estimates show cross-system flows.
What it means
The interesting recommendation is the third one, and it is not a compliance point. ACER asks the Irish regulator to consider, at the next review, whether pricing gas transport off the marginal cost of expanding the network still makes sense in a system where gas demand is expected to decline. A forward-looking expansion-cost method is built for a growing pipe. Applied to a shrinking one, it prices an expansion nobody intends to make, and the allowed revenue still has to come from somewhere — which means from fewer units, carried by whoever is left.
A tariff review is where the energy transition becomes arithmetic. Nothing here is about climate policy; it is about which line in a matrix recovers which cost. But the choice ACER is flagging — expansion costs versus historical costs — decides how the bill for an underused network is split between remaining shippers, and that question is arriving in every gas system in Europe in roughly this order.
And the Corrib point is a reminder that classification is not paperwork. Whether a piece of pipe is "transmission" or something else decides which code governs its charges, which discounts apply, and who can challenge them. Ireland is being asked to say which one it is, in writing, before December.