TenneT proposes removal of Poland-Lithuania interconnector reference and >15-minute settlement option from FSkar balancing settlement methodologies

TenneT submitted a proposal to ACM on 10 August 2026 to amend the FSkar (Financial Settlement k∆f, ACE and ramping period) methodologies under EB Regulation Articles 50(4) and 51(2). The two changes are: (1) deleting the reference to the Poland-Lithuania interconnector in the FSkar methodologies for non-synchronously connected TSOs, reflecting the Baltic states joining the Continental Europe synchronous area on 9 February 2025; and (2) removing the option for TSOs to apply a settlement period longer than 15 minutes, aligning with harmonisation of the imbalance settlement period at 15 minutes and introduction of the 15-minute market time unit in SDAC.

FSkar governs how balancing-related energy exchanges (e.g. frequency containment process energy) between non-synchronously connected TSOs are financially settled. Removing the obsolete Poland-Lithuania reference reflects the completed Baltic synchronisation with Continental Europe, while eliminating longer settlement periods forces full alignment with the EU-wide move to 15-minute imbalance settlement and SDAC market time units, reducing methodological fragmentation across synchronous area borders.

This is a technical but consequential cross-border balancing settlement methodology update tied directly to two structural EU market changes: the 2025 Baltic desynchronisation from Russia/Belarus and synchronisation with Continental Europe, and the broader EU harmonisation of imbalance settlement periods to 15 minutes under SDAC. By stripping the now-obsolete PL-LT interconnector reference and closing the loophole for longer-than-15-minute settlement periods, TenneT is tidying up EB Regulation Art 50(4)/51(2) methodologies to prevent inconsistent application among non-synchronously connected TSOs. While narrow in scope, the change reinforces the trend toward standardised 15-minute settlement granularity across Europe's balancing markets and removes a legacy artifact from the pre-2025 synchronous area map, with knock-on relevance for any future non-synchronous interconnections.

EU Regulation 2017/2195 (Electricity Balancing Regulation), Articles 50(4) and 51(2)

Public consultation deadline for stakeholder responses · 18 Sept 2026

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