Source - RFG (EU 2016-631)

Commission Regulation (EU) 2016/631 of 14 April 2016 — the Requirements for Generators (RFG) network code. Establishes harmonised EU requirements for the grid connection of power generating modules (kraftproduktionsmoduler): synchronous generators, power park modules (kraftparksmoduler — wind, solar, batteries connected via power electronics), and offshore power park modules.

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Summary

RFG establishes technically detailed connection requirements for generating units, graduated by size and voltage level. The regulation’s core purpose is system security: generators must remain connected, respond appropriately to frequency and voltage deviations, and support grid recovery. Requirements differ substantially between generator types (synchronous vs. power park modules) and between the four size categories (types A–D).

For the flexibility wiki, the most relevant aspects are: (1) the type classification system that determines which generators can participate in which markets; (2) the ramp-rate advantage of kraftparksmoduler (batteries, solar, wind) relevant to fast-response flexibility services; and (3) the FSM (Frequency Sensitive Mode) capability requirement for larger generators, which is a precondition for TSO reserve participation.

Key content

Type A–D classification (Nordic thresholds, Art. 5, Table 1)

Type A thresholds (0.8 kW at <110 kV) mean virtually all small DERs — residential batteries, home solar, EV chargers — fall into Type A and face only minimal requirements. This is a deliberate regulatory choice to facilitate distributed generation uptake.

Power park modules vs. synchronous generators

The regulation distinguishes synkrona kraftproduktionsmoduler (traditional generators with rotating mass, inherent inertia) from kraftparksmoduler (PPM — units connected via power electronics: wind farms, solar PV, battery storage). Key differences:

• Kraftparksmoduler have no natural inertia — they cannot provide the passive frequency stabilisation that synchronous machines give automatically.
• However, kraftparksmoduler can ramp output extremely fast. Swedish EIFS 2018:2 specifies 100 %/min ramp rate for kraftparksmoduler, compared to 4–40 %/min for conventional thermal/hydro (see Source - EIFS 2018-2 Nätanslutning av generatorer).
• This speed advantage makes kraftparksmoduler (especially batteries) highly suitable for fast-response Flexibility services, but their absence of inertia is a growing system stability concern as synchronous generation retires.

FSM (Frequency Sensitive Mode)

FSM (frekvenskänslighetsläge) is an active frequency-response mode where a generator modulates output in proportion to measured frequency deviation. Under EIFS 2018:2 §23: FSM capability is required for Type C and D generators, but FSM is only activated when ordered by the TSO (Svk). This is a capability obligation, not a continuous operating obligation.

FSM is the technical precondition for participation in primary frequency reserves (Balancing Markets — FCR products). Type A and B generators do not need FSM capability and therefore cannot participate in FCR markets without a separate derogation or waiver process.

Exclusion of energy storage (Art. 3.2.d)

The regulation explicitly excludes kraftlagringsenheter (energy storage units) from its scope, except for pumpkraftstationer (pumped hydro). In practice, grid-scale batteries connected for power production are typically classified as kraftparksmoduler and treated under the PPM requirements. This creates some regulatory ambiguity for battery storage that can both consume (storage) and produce (dispatch) — the Swedish implementation in EIFS 2018:2 applies PPM requirements to batteries operating in production mode.

Derogation mechanism (Arts. 60–63)

NRAs (national regulatory authorities) may grant derogations from individual RFG requirements on application from generator owners or TSOs. Ei is required (Art. 61) to specify derogation criteria publicly. See Source - Ei RFG Undantagskriterier (2017) for the seven criteria Ei adopted in 2017.

Derogation grounds: local exceptional circumstances where compliance would endanger local grid stability, or where safe operation requires conditions incompatible with the regulation.

Existing generators (Art. 4)

RFG applies to new generating modules. Existing generators are generally exempt unless:

• Significant modification requiring a new connection agreement (for Type C/D)
• The NRA or TSO proposes extension to existing plants after cost-benefit analysis

This grandfather clause is significant for Sweden’s large base of existing hydro and nuclear, which are not required to retrofit FSM or other capabilities unless substantially modernised.

Relevance to wiki topics