ACER Decision 05-2025 FNAM Annex I (2025)

ACER Decision 05-2025, Annex I: Type and format of data and the methodology for TSOs’ and DSOs’ flexibility needs analysis. Full operative text of the FNA Methodology (FNAM) approved by ACER under Article 19e(4) of Regulation (EU) 2019/943.

Type: ACER decision approving the FNA methodology (Annex I to the decision); the methodology places obligations on TSOs and DSOs. Legal basis: Article 19e(4), Regulation (EU) 2019/943 (as amended by Regulation 2024/1747).

Document structure

The FNAM is organized as 18 articles + 3 annexes:

• Arts. 1–5: Scope, definitions, roles and responsibilities, national implementation timeline, confidentiality
• Arts. 6: Data and analysis requirements (common inputs)
• Arts. 7–10: System flexibility needs (RES integration, ramping, short-term)
• Arts. 11–12: Network flexibility needs (DSO and TSO levels)
• Art. 13: Unavailability of flexible resources due to grid prequalification
• Art. 14: Fine-tuning system needs with network needs
• Art. 15: Market barriers and digitalization evaluation
• Art. 16: Guiding criteria for assessing flexibility sources
• Arts. 17–18: Amendments and language
• Annex 1: TSO input data — type and format (Tables 1–14, incl. Table 14 FNA results)
• Annex 2: DSO input data — type and format (Table 15 — the central DSO reporting template; Tables 16–18 are worked examples)
• Annex 3: Fine-tuning process illustration

Key claims and methodology

Two types of flexibility needs

The FNAM distinguishes:

1. System flexibility needs — needed to adjust to variability of generation and consumption at system level (bidding zone scale):

   • RES integration needs (Art. 8): flexibility to reduce renewable curtailment and achieve RES targets
   • Ramping needs (Art. 9): flexibility to cover expected variation of residual load under perfect forecast conditions
   • Short-term flexibility needs (Art. 10): flexibility to cover unexpected variations (forecast errors, forced outages); overlaps with frequency restoration reserve (FRR) capacity

2. Network flexibility needs — locally- and time-specific; prevent or solve congestion or voltage issues:

   • DSO network needs (Art. 11): assessed by individual DSOs or jointly
   • TSO network needs (Art. 12): transmission-level congestion and RES curtailment

DSO network flexibility needs (Art. 11)

DSOs must quantify upward and downward network flexibility needs per target year as:

• If available: summation of local maximum values of power (MW) and total energy (MWh) during time blocks and/or representative days for each target year
• Minimum data set: summation of local maximum values of MW and MWh per target year (no time-block breakdown)

Needs are detailed per direction and, if applicable, per scenario, at a spatial granularity no coarser than the bidding zone (or Member State area if there is only one bidding zone). To be used in fine-tuning of RES integration needs, a DSO must also identify the share of its downward needs that pertains to RES curtailment (Art. 11.7); otherwise that data is not used.

Critical limitation (Art. 11.3): if a DSO cannot provide quantitative data, qualitative information may be submitted to the designated authority — but qualitative data cannot be used in the fine-tuning process under Art. 14. This creates a tiered system where quantitative DSOs get their network needs incorporated into system-level assessment; DSOs reporting only qualitative data do not.

DSOs must also provide reasoning including the potential effects of existing or planned frameworks and of incentives to connect additional generation, load, storage or other flexible resources (Art. 11.6). If available, they also provide the expected contractual means to access flexibility, such as local services or flexible connection agreements (the latter corresponds to Swedish villkorade avtal).

Fine-tuning threshold (Art. 14)

The TSOs fine-tune system needs only for the relevance criteria in Art. 14(3) that are met (Art. 14.5–14.6):

• (a) RES integration needs vs. downward transmission network needs: annual RES curtailment due to transmission constraints must exceed 10% of the Art. 8 RES curtailment
• (b) RES integration needs vs. downward distribution network needs: annual RES curtailment due to distribution constraints (as provided by DSOs) must exceed 10% of the average Art. 8 RES curtailment
• (c) All system needs, for unavailability of flexible resources due to prequalification and temporary limits: maximum hourly unavailability must exceed 10% of the installed capacity of flexible resources; only this criterion triggers fine-tuning of ramping and short-term needs

National implementation timeline (Art. 4)

The FNA report itself is to be adopted within 12 months of each cycle’s start; deadlines in Art. 4(1), (2) and (4) may be deviated from with the designated authority’s agreement if that does not affect this (Art. 4.8).

Sweden’s trilateral agreement (Svk + Energiföretagen + Ei) was signed 25 November 2025 — exactly at the Art. 4 deadline. Ei set the DSO submission deadline at 7 April 2026 (Source - Ei FNA Method Page (2025)), inside the 10-month window.

Market barrier categories (Art. 15)

The FNAM specifies six formal categories for evaluating market barriers to flexibility. TSOs and DSOs must provide data on each where relevant:

1. Lack of proper legal framework for market access to new entrants and small actors
2. Lack of enablers and incentives to provide flexibility
3. Restrictive requirements to provide balancing services
4. Restrictive requirements to provide congestion management
5. Complex, lengthy, and discriminatory administrative requirements
6. Lack of regulatory incentives to system operators to consider non-wire alternatives

Category 6 is the FNAM’s formal label closest to the CAPEX bias / lösningsneutralitet problem in Swedish revenue regulation (wiki reading; the annex does not use those terms).

DNDP as primary data source (Whereas 22)

“DNDPs might not always be available since Member States may not require them from the integrated electricity undertakings with fewer than 100,000 customers or serving small isolated systems. In those cases, the data required for the FNA methodology may be based on other relevant data sources.”

This confirms the DNDP as the default primary source for DSO distribution-level FNA data, with alternative data sources as fallback only.

Guiding criteria (Art. 16)

Article 16(4) requires DSOs to provide, per distribution network flexibility need and target year: location (geographic and voltage level), direction (up/down), the timeframe in which the resource must be available (including, if available, duration, frequency of activation, cumulated energy per time block and applicable economic criteria), the local maximum power required, and other criteria agreed with the designated authority. The indicators are based on local-service procurement information and Table 15, or other studies if available; any part of a need not expected to be covered at distribution level must be flagged with reasoning.

Relevance to existing wiki content

• Flexibility Need Assessment — primary document for this page; closes the “ACER Decision 05-2025 (FNAM) full text” data gap
• Distribution Network Development Plan — DNDP confirmed as primary data source for FNA at distribution level
• Electricity Market Design Reform 2024 — FNAM is secondary legislation under Art. 19e of Regulation 2024/1747
• Flexibility Market — market barrier categories provide formal EU taxonomy for Swedish barriers
• Villkorade Avtal — Art. 11 requires DSOs to report contractual means including flexible connections
• Congestion Management — network flexibility needs definition and fine-tuning process