On April 8th, the next step of the Flow-based Capacity Calculation methodology has been implemented in the Month-ahead timeframe by the Nordic Transmission System Operators (TSOs), Fingrid, Svenska kraftnät, Statnett and Energinet, facilitated by the Nordic Regional Coordination Centre (RCC). The implementation is part of a broader transformation where flow-based capacity calculation is rolled out for different market timeframes.
Since October 2024, the Day-ahead market capacities have been calculated based on the Flow-based Capacity Calculation methodology, which reflects the physical grid to a greater extent. From October 31st, 2025, the Flow-based Capacity Calculation methodology has been used for the calculation of long-term forecasted capacities one year ahead. From April 8th, 2026, the Flow-based Capacity Calculation methodology is also used for the calculation of forecasted long-term capacities one month ahead.
With Flow-based implemented in both the Day-ahead and the Long-term timeframes, consistency and transparency of capacity calculation across timeframes is strengthened. It should be noted that the long-term capacity calculations (LTCC) are based on predefined scenarios. As a result, the outcomes may vary depending on the scenario used and can differ from capacity calculations for other timeframes.
The implementation is part of a broader transformation to the Flow-based Capacity Calculation methodology in all timeframes, which will make markets reflect the actual physics of the grid to a greater extent and release more accurate capacities to be traded in the markets. This improvement is key to enabling the green energy transition, which requires market design to supplement the needed build-out of the grid to integrate more renewable energy in the system.
The next steps of the implementation of Flow-based Capacity Calculation are the continued implementation of Flow-based in the Intraday timeframe and further improvements to long-term capacity calculation processes.
Furthermore, building on this strong foundation, the LTCC project will continue improving outage information published on the Nordic Unavailability Collection System (NUCS) platform. These developments will introduce flow-based parameters for outage impact assessments alongside the existing NTC-based approach, improving accuracy, consistency, and transparency. Over time, this supports a transition towards a fully flow-based representation of outage impacts and stronger alignment across timeframes.
Facts
The Flow-based (FB) Capacity Calculation replaces the Net Transfer Capacity (NTC) methodology, which is currently still applied in the Intraday and Balancing timeframes. Flow-based reflects the actual grid in a more optimal way by incorporating the internal physical constraints of the power grid into the calculation.
Flow-based Capacity Calculation methodology finds its origin in the Capacity Allocation and Congestion Management (CACM) Guideline and Forward Capacity Allocation (FCA) Guideline.
Contact:
Nordic Chairman of Long-Term Flow-based Project.
Nikolaj Nåbo Andersen, +4523338993, nae@energinet.dk
Read more here:
Flow-based – Nordic Regional Coordination Centre