The Nordic Transmission System Operators (TSOs), Fingrid, Svenska kraftnät, Statnett and Energinet, facilitated by the Nordic Regional Coordination Centre (Nordic RCC), will introduce publication of outage impact based on Flow-based Methodology through the Nordic Unavailability Platform (NUCS) in September 2026.
The new Nordic Market Availability (NORMA) business process provides Flow-based assessments of the impact of planned transmission grid outages on the Nordic Capacity Calculation Region’s Flow-based domains. The first publications will cover both the Month-ahead (M-1) and Week-ahead (W-1) time horizons, with the first M-1 publication scheduled for 24 September 2026 and the first W-1 publication scheduled for 25 September 2026.
The introduction of NORMA addresses an important gap following the transition to Flow-based capacity calculation. Since the Nordic Day-ahead market moved to Flow-based Market Coupling in October 2024, capacity has been calculated using a methodology that reflects the physical characteristics of the Nordic power system. However, outage information has continued to be communicated primarily through Net Transfer Capacity (NTC)-based Urgent Market Messages (UMMs). NORMA complements this information by providing an assessment of outage impacts in a Flow-based context.
Initial release and how the information should be interpreted
The September release establishes the core NORMA capability for publishing Flow-based outage impact assessments for individual transmission grid outages across the M-1 and W-1 time horizons. The publications are intended to provide additional transparency and forward-looking information on the potential impact of outages on Flow-based capacity. The existing NTC-based outage publications will continue alongside on the NUCS platform, meaning the new Flow-based publications complement rather than replace existing outage information.
The published results should be understood as indicative assessments of expected Flow-based conditions under the relevant calculation assumptions, rather than accurate forecasts of the capacity which is ultimately unavailable in the market. Published Flow-based domains and bidding zone net positions may therefore differ from those observed in Day-ahead Capacity Calculation.
This release covers selected transmission grid elements and outage types. Some asset types and outagespecific network constraints are not yet fully represented in the Flow-based calculations. For instances where an outage impact cannot currently be calculated, the information regarding outage impact will instead only be available in the existing NTC-based UMMs.
There are also some differences in how outage periods are represented compared with existing NTCbased publications. The initial Flow-based publications use the outage start and end times provided by the TSOs and do not currently capture temporary reconnections, such as during nights or weekends. In such cases, the intact Long-Term Capacity Calculation (LTCC) reference provides the latest available Flow-based reference. At go-live, the validation and the visibility into outage-adjusted Flow-based domains at the TSOs will be limited, and this will be a priority to enhance going forward.
These limitations form part of the initial implementation and are transparently communicated to support appropriate interpretation of the results. Additional information on the methodology, scope and current implementation limitations is available in the NUCS Market Participant Handbook.
Improving transparency on the impact of outages
For the first publications made via the NORMA process, the impact of individual transmission grid outages is calculated using Long-Term Flow-based Capacity Calculation results as the reference. The resulting Flow-based outage impact assessments are published through the NUCS platform. Future releases will progressively expand the scope to include assessments of combinations of simultaneously occurring outages in the Nordic Capacity Calculation Region.
The publications provide market participants with additional insights into how planned transmission outages may affect Flow-based domains and the associated import and export capabilities of Nordic bidding zones. The W-1 process provides an updated week-ahead view based on the latest available outage plans. The M-1 process provides month-ahead information on the expected impact of individual transmission grid outages, with publications available from the following month until the end of the calendar year.
Preparation of existing outage publications
As part of the preparation for the Flow-based outage impact publications, the Nordic TSOs have been updating previously issued Unavailable Capacity messages to include the relevant TSOOutageID. This will enable mapping between existing NTC-based Unavailable Capacity messages and the new Flow-based outage information. As a result of these updates, the original messages will be replaced.
Continued development
The introduction of NORMA marks another step in the ongoing transition towards greater consistency and transparency across Flow-based Capacity Calculation time horizons.
The September release represents the initial implementation of the NORMA process and NUCS Flowbased publication capability. Further development activities are already underway and future releases will build on operational experience and stakeholder feedback, including the phased introduction of assessments for combinations of simultaneously occurring outages, with the aim of expanding the scope of the calculations and improving the completeness, usability, granularity and operational efficiency of the published information.
This phased approach is consistent with the target-state development, as described in the NUCS Market Participant Handbook, where the initial release prioritizes core capabilities for market transparency and operational readiness, followed by further enhancements. The implementation is the result of continued collaboration between the Nordic TSOs and Nordic RCC.
Contact
Please direct any questions about this matter to Erik Ek, Chair of the Nordic Flow-Based Implementation Program through the Svenska kraftnät press office, Phone: +46 10 475 80 10, e-mail: press@svk.se
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