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Svk Om Ö-drift (2025)

Source Updated 2026-09-21 Cited by 3 pages
Source details
Type
Web page
Publisher
Svenska kraftnät
Published
2025-04-02
Link
svk.se/sakerhet-och-beredskap/elberedskap/om-odrift/

“Om ö-drift” — Svenska kraftnät’s authoritative web page on island operation as an electricity preparedness (elberedskap) measure. Published 2025-04-02. The primary public statement of Svk’s role, taxonomy, and technical requirements for ö-drift in Sweden.

Key content

Definition and framing

Ö-drift is defined as operating an area as an “island” with local electricity production, without connection to the wider grid. Svk’s framing is important: a national, interconnected electricity supply is the best outcome for Sweden. Ö-drift is explicitly positioned as a fallback measure for “riktigt svåra situationer” (genuinely severe situations) — prolonged transmission failures where national restoration plans cannot quickly restore the grid. It is not a normal operating mode.

Four-level taxonomy

Svk distinguishes four scales of ö-drift in Sweden:

  1. Transmission-based ö-drift — for restoring the power system when all of Sweden, or large parts of it, has lost power. Svk is responsible, in accordance with EU regulations (EU:s regelverk).
  2. Local/regional ö-drift — for a town, city, or municipality, or parts thereof. Svk acts in its elberedskapsmyndighet role: gives support to secure local capability (förmåga), planning (planering) and testing (provning). Scale: a locality (ort), town, municipality or parts thereof.
  3. Small area / single facility — e.g., an agreement with the owner of a small hydropower plant to use it for a specific area or facility. Outside Svk’s area of responsibility (ansvarsområde); questions go to the local electricity company.
  4. Individual building — e.g., solar panels combined with battery storage. Entirely outside Svk’s scope; questions directed to the local electricity company (DSO).

Svk’s elberedskapsmyndighet role (local/regional ö-drift)

For level 2 (local/regional), Svk can:

  • Financially compensate costs for maintaining ö-drift capability (förmåga)
  • Support planning (planering)
  • Support and fund testing/simulation exercises (provning)

Limitation: Svk can only decide on preparedness measures towards actors within the electricity supply chain. It cannot make decisions towards municipalities or other actors that are not part of the electricity supply.

Technical requirements

For a local/regional ö-drift to function, the following capabilities must exist in the target area:

Core requirement — black start (dödnätsstart): Svk calls this the most central prerequisite: local generation that can start from a dead grid. Without local generation, ö-drift is not possible. For local/regional ö-drift the plant must be connected to the local or regional grid.

Frequency and voltage regulation: Local generation must also be able to regulate frequency and voltage in the island. Production and consumption must be balanced continuously for as long as the ö-drift lasts, which places high demands on regulation and balancing capability. The elnätsbolag (network company) is ö-driftsledare and responsible for regulating frequency and voltage.

Weak-grid operation: The island network is operated as a svagt nät (weak grid) “with everything that entails”, for example handling much lower short-circuit currents than normal. Svk describes weak-grid operation as complicated and risky.

Organizational capabilities:

  • A plan (ö-driftsplan) for how to run the ö-drift in a live situation
  • Personnel with the right competence, and an organisation prepared for a situation far more demanding than normal
  • Responsibility for running ö-drift in a live situation is regulated in each ö-driftsplan

Limitations and uncertainties

  • Cannot fully test: it is not possible to drill live in full, so function cannot be guaranteed with 100% certainty. Svk says it is “a good way along” through testing (provningar) and simulations.
  • Hard load prioritization: in most ö-drifts, only the most critical societal functions will receive electricity. Other consumers must have their own backup (generators etc.).
  • Complexity and risk: operating a weak grid is described as complicated and risky.

Process for live ö-drift

Three sub-processes: (1) Säkerställa tekniska förmågor — ensuring technical capabilities are in place; (2) Ö-driftplanering — developing and maintaining the plan; (3) Skarpt läge — executing when needed, following the plan, communicating with all stakeholders, and re-connecting to the national grid when possible.

Relevance

This source provides the policy and preparedness framing for island operation that the existing technical microgrid sources (Arholma, Simris) lack. The taxonomy suggests (wiki inference, not stated by Svk) that Arholma and Simris are level-2 or level-3 cases, with the DSO as ö-driftsledare — while Svk’s transmission-based restoration is a separate, system-wide function. The elberedskap funding mechanism (Svk compensates local capability costs) is not documented elsewhere in the wiki.

Cited by 3