NTC (Net Transfer Capacity)
Net Transfer Capacity (NTC) is the maximum exchange of active power between two bidding zones compatible with operational security, after subtracting a reliability margin from Total Transfer Capacity. CACM Regulation (EU) 2015/1222 calls the broader concept "cross-zonal capacity" and recognises two methodologies — flow-based and coordinated NTC. The Baltic CCR currently uses coordinated NTC for both day-ahead and intraday capacity.
Net Transfer Capacity (NTC) is the maximum exchange of active power between two bidding zones that is compatible with operational security limits, after subtracting a Transmission Reliability Margin (TRM) from Total Transfer Capacity (TTC): NTC = TTC − TRM. CACM Regulation (EU) 2015/1222 calls the broader concept "cross-zonal capacity" (Article 2(7)) and recognises two methodologies in Article 20 — flow-based (preferred for highly meshed grids) and coordinated NTC (cNTC).
NTC vs ATC
NTC is what the TSOs calculate as theoretically available before any market activity. Available Transfer Capacity (ATC) is what is left after long-term auctions and other prior allocations: ATC = NTC − already-allocated capacity. ATC is the value handed to Nord Pool / SDAC for day-ahead market coupling.
Baltic CCR uses cNTC
The Baltic CCR covering the EE–LV, LV–LT, EE–FI/EstLink, LT–SE4/NordBalt and LT–PL/LitPol borders applies coordinated NTC for both day-ahead and intraday timeframes; the latest Baltic DA/ID Capacity Calculation Methodology was approved on 21 November 2024. The TSOs argued that flow-based offers no added value in a radially connected system without parallel paths. By contrast Core CCR has been flow-based since June 2022 and Nordic CCR went flow-based in 2024.
Why it shows up in price news
When NTC on a Baltic border is reduced — typically for a planned outage on EstLink, NordBalt or the LV–LT corridor — day-ahead prices in EE diverge from the rest of the coupled zone. The Baltic Transparency Dashboard publishes daily NTC values per direction per border. After the 9 February 2025 synchronisation with Continental Europe, the previous Russia/Belarus tie-line capacities are gone from the calculation entirely.
Sources
CACM Article 20 · Baltic DA/ID CCM (21 Nov 2024) · ENTSO-E: Capacity Calculation Regions