Vattenfall Eldistribution

Vattenfall Eldistribution AB is Sweden’s largest distribution system operator (DSO) by network area, a wholly owned subsidiary of Vattenfall AB. It operates both regionnät (regional 40–220 kV grid) and lokalnät (local 10–20 kV and LV grid) across a large geographic footprint spanning northern, central, and parts of western and eastern Sweden.

Network overview

Five operating areas

Vattenfall divides its network into five areas for planning and reporting. These areas are coarser than county boundaries, justified by the geographic structure of the regional grid and NDA requirements for large industrial customers.

Flexibility stance — no market-based procurement

Vattenfall has explicitly stated that it sees no conditions for market-based flexibility services at any of its constrained locations. From the DNDP:

“Vattenfall Eldistribution AB:s bedömning är att det i dagsläget inte finns förutsättningar för marknadsbaserade flexibilitetstjänster på dessa platser, varför bilaterala avtal med de enskilda verksamheterna övervägs.”

Vattenfall’s threshold for a viable flexibility market:

• Supply ≥ 5× demand
• ≥ 5 independent actors
• No single actor providing >50% of supply

Their assessment: these conditions are not met anywhere in their network. The operative tool is Villkorade Avtal with individual industrial customers.

This stance directly explains why Vattenfall reports N/A for all flexibility service needs in Ei’s DNDP data tool — a deliberate policy choice, not a reporting gap. (Source - Vattenfall Eldistribution Nätutvecklingsplan 2025-2034)

Cost comparison: grid vs flexibility

Vattenfall performed an explicit cost comparison for the DNDP (Section 3.1.2):

The ratio (~15–30×) is their primary quantified argument against market-based flexibility as a grid substitute. Vattenfall acknowledges this is a theoretical calculation and that few actors currently meet technical requirements for grid-replacing flexibility services. (Source - Vattenfall Eldistribution Nätutvecklingsplan 2025-2034)

Compare with E.ON Energidistribution, which quantifies grid upgrade cost at an average 1.09 MSEK/MW (with flexibility as an alternative to investment) — a different calculation framing but in the same order of magnitude as Vattenfall’s grid cost figure.

Villkorade avtal

Vattenfall actively uses Villkorade Avtal (conditional connection agreements) in two contexts:

• Mellan area (Uppsala): local grid villkorade avtal for large customers in the Uppsala sub-grid
• Stockholm area: local grid villkorade avtal for customers in the Stockholm local grid

Villkorade avtal in Norr (large industry) and Väst (petrochem/industrial) are also active where stamnät subscription has not yet been granted. (Source - Vattenfall Eldistribution Nätutvecklingsplan 2025-2034)

The OpenADR standardization effort (Source - Energiföretagen Branschrekommendation Conditional Grid Connections (2023)) tested Vattenfall R&D’s VEN implementation in a PoC with SWITCH (E.ON’s platform) — confirming cross-DSO OpenADR compatibility at the protocol level.

Flex market pilot closures

Vattenfall has closed both of its local flexibility market pilot projects:

Uppsala pilot (UppFlex, CoordiNet-era extension):

• Ran as an extension of CoordiNet infrastructure using SWITCH platform
• Operated V2023/24 only
• Closure statement: “Med nya förutsättningar har Vattenfall Eldistribution beslutat att avveckla detta pilotprojekt”

Stockholm pilot (sthlmflex participant):

• Participated in sthlmflex at the regionnät level (not as a platform operator)
• Addressed Svk subscription management, not local grid congestion
• Closure statement: same language — “Med nya förutsättningar har Vattenfall Eldistribution beslutat att avveckla detta pilotprojekt”

The “new conditions” (nya förutsättningar) are not specified in the DNDP. Context: sthlmflex closed when warm winters + high energy prices + TSO subscription grants combined to remove the market driver. UppFlex closed due to insufficient liquidity — the CoordiNet liquidity threshold was not met organically. (Source - Vattenfall Eldistribution Nätutvecklingsplan 2025-2034)

Arholma microgrid

See Island Operation for the general ö-drift framework, Svk taxonomy, and comparison with Simris. Vattenfall Eldistribution operates a grid-connected islanding microgrid on the island of Arholma in the northern Stockholm archipelago (~250 residents). The system was commissioned in August 2023 and is an active R&D project. (Source - Vattenfall Arholma Microgrid (2025))

Technical specification: Two 160 kW lithium-ion battery systems (48 lithium-ion cells each, 336 kWh per unit, 672 kWh total). Operational communications describe the system as a “two-hour system.” A Lund University thesis (2025) working with Vattenfall R&D specifies the formal design target as 1 hour of island supply at 99% probability — consistent with the pre-commissioning Energiforsk reliability study that treated 320 kW × 1 hour as the design unit. The difference likely reflects full BESS capacity (672 kWh / 320 kW ≈ 2.1 hours nominal) vs the 99th-percentile reliability target under variable winter load. Real-time control software detects mainland cable faults in milliseconds, triggering automatic ö-drift. (Source - Vattenfall Arholma Microgrid (2025), Source - Lund Arholma Microgrid Fault Detection (2025), Source - Energiforsk 2023-948 Reliability Analysis Microgrid (2023))

Institutional model: The project uses a Power-as-a-Service structure where Vattenfall Elanläggningar (part of Vattenfall Network Solutions) owns and operates the BESS hardware and delivers it as a capacity service to Vattenfall Eldistribution. Vattenfall Eldistribution is the DSO client. This arrangement is consistent with Art. 36 DSO storage ownership restrictions even within the same corporate group.

Reliability improvement: A pre-commissioning Energiforsk reliability study (2023) using actual Arholma load data (Oct 2015–Jun 2019) and the 2×160 kW BESS spec quantified the reliability benefit of island capability:

The dominant upstream failure is the mainland submarine cable: failure rate 2.1 f/yr (the most frequent event), mean repair time 2 hours. When the cable fails, island mode activates; the 45% SAIDI improvement in full-island mode reflects how much customer outage time is prevented by local supply. In realistic hybrid mode (grid-connected the vast majority of the time), the improvement is −18% in SAIDI — still material. (Source - Energiforsk 2023-948 Reliability Analysis Microgrid (2023))

Capacity adequacy — the case for DSR: The same study found the local generation insufficient for 130 hours/year (LOLP 1.5%) — typically winter nights when solar output is zero and load peaks exceed battery discharge capacity. This quantifies exactly why customer demand-side resources are needed in addition to the battery.

Next phase — customer DSR (planned 2025): Vattenfall is extending the microgrid control system to include customer assets: remote-controlled switches at customer premises (heat pumps, electric floor heating, heat storage) that can be sequentially reconnected after island mode ends, preventing cold-load pickup (simultaneous reconnection causing a new overload). Compensation to participating customers: discount on the grid tariff, not a market payment. The ongoing NextGen Arholma project (referenced in the Lund 2025 thesis) investigates customer inclusion and flexibility to strengthen the microgrid further.

Protection engineering — pre-commissioning design: The Arholma protection system design is documented in the Energiforsk 2023:957 industry guidance report (based on an interview with Arne Berlin, Firas Daraiseh, and Yiming Wu at Vattenfall R&D in February 2023, when FAT was complete but the system had not yet been commissioned). Vattenfall’s requirement: protection must not be worse in island mode than in grid-connected mode, for both detection capability and disturbance frequency. MV ground faults are handled by zero-sequence voltage protection (nollpunktsspänningsskydd) at 3 kΩ sensitivity — non-selective (any MV ground fault blackouts the island). ROCOC (di/dt, rate-of-current-change) protection on battery terminals detects high-resistance LV ground faults during island mode. Relay settings change on island mode entry via communication; multiple technologies evaluated (4G, IEC 61850, fiber). Some LV substations not modernized → those LV faults handled by MV protection for economic reasons. (Source - Energiforsk 2023-957 Felbortkoppling i Mikronät (2023))

APRS: Vattenfall has procured an Adaptive Power Restoration System (APRS) for Arholma — advanced logic for automated network reconfiguration after fault isolation. After primary fault clearing, APRS identifies faulted segments, evaluates reconfiguration options via load flow analysis, checks for overload and voltage risks, and either executes automatically or provides decision support to operators. APRS is distinct from the protection relay layer — it acts after fault clearing to restore supply to unfaulted sections. (Source - Energiforsk 2023-957 Felbortkoppling i Mikronät (2023))

Protection simulation (2025): A 2025 Lund University MSc thesis done in collaboration with Vattenfall R&D simulated the Arholma grid’s protection system in island mode. Key findings relevant to microgrid design: inverter current limitation (max 2 p.u. for grid-forming inverters vs 6 p.u. for synchronous generators) causes conventional protection devices to malfunction in island mode; LVCBs (low-voltage circuit breakers) with updatable settings at island entry are essential for clearing LV faults; MV-only protection is viable within calculable limits as a cost-reduction option. See Source - Lund Arholma Microgrid Fault Detection (2025) for full technical detail.

Relevance to flex stance: Arholma demonstrates that Vattenfall does engage with active demand-side management — but through implicit demand response (rules-based DSO control, tariff discount compensation) rather than market-based explicit procurement. Vattenfall’s skepticism is specifically about competitive flexibility markets, not about load control itself. This distinction matters for interpreting the “no conditions for market-based flex” position in the DNDP. See Vattenfall vs E.ON — DSO Approaches to Flexibility.

Investment programme

Vattenfall plans 22 major regional grid investments 2025–2034, covering ~90% of growth-driven investment. 75% of total investments are for asset renewal and safety (not DNDP-scope). Key projects:

Full investment table: Source - Vattenfall Eldistribution Nätutvecklingsplan 2025-2034.

Local grid growth (Bilaga 1)

Vattenfall publishes municipality-level local grid forecasts (incremental kW, 2025–2034) as Bilaga 1. Local growth is ~110 MW in 2025 rising to ~623 MW by 2034 — a separate, smaller scale from the regional grid’s ~7,500 MW growth.

Largest local growth municipalities:

• Uppsala: 11,600→67,580 kW
• Sigtuna: 4,920→26,590 kW
• Nyköping: 5,290→30,620 kW

Relationship to other wiki pages

• Distribution Network Development Plan — Vattenfall’s DNDP is the second major Swedish DSO DNDP in the wiki (after E.ON Energidistribution)
• Flexibility Market — Vattenfall closed both pilot markets; explains the N/A in Ei data tool
• Villkorade Avtal — Vattenfall’s active use in Uppsala and Stockholm local grids
• SWITCH — Vattenfall used SWITCH for UppFlex; participated in CoordiNet; OpenADR PoC
• NordSyd — Project 11 (NordSyd Västeråsbenet) is directly relevant to Vattenfall’s Mellan area
• CoordiNet — Vattenfall was a participant DSO in the CoordiNet demonstration
• E.ON Energidistribution — the primary comparison DSO; different flex philosophy
• Ei — regulatory authority; Vattenfall participates in FNA 2026 as a signatory DSO

Data gaps

• Regulatory approval status of Vattenfall’s villkorade avtal methodology (cf. E.ON received approval March 2024)
• Bilaga 1 coverage gap: some municipalities excluded due to “few subscribers and low growth” — which ones?
• Whether Vattenfall will change its flex market stance as the NC DR framework is implemented (derogation requirements)
• Vattenfall’s FNA 2026 submitted data (reporting chain to Svk)