Source - sthlmflex säsong 3 (2022-2023)

Full title: sthlmflex rapport vintern 2022/2023 Authors: Vattenfall Eldistribution, Ellevio, E.ON Energidistribution (Håkan Borgstrand), Svenska kraftnät Published: 2024-12-09 Pages: 37 Raw file: raw/sthlmflex-rapport-vintern-2022-2023.pdf

Summary

Final season report for sthlmflex’s third and last winter of operation (December 2022 – March 2023). Covers market architecture, products, load forecasting, prequalification, and market results for the 2022/2023 season, plus lessons learned from all three seasons. E.ON Energidistribution joined as a new project participant in season 3 (at the lokalnät level).

Institutional context

Parties:

• Svenska kraftnät — project owner (FoU); TSO; subscription manager; mFRR
• Vattenfall Eldistribution — regionnätsbolag (Stockholm Norra)
• Ellevio — regionnätsbolag (Stockholm City + Stockholm Södra)
• E.ON Energidistribution — lokalnätsbolag (joined S3 only; no abonnemangsväxling applicable)

Platforms:

• NODES — market operator platform (bid management, clearing, settlement, baseline validation)
• SWITCH flex tool — DSO operator interface (load forecasting, grid state, subscription management, dispatch); referred to in the report as the tool “developed by E.ON” used by the grid companies

Market geography

Four market areas: Stockholm Norra (Vattenfall), Stockholm City (Ellevio), Stockholm Södra (Ellevio), and E.ON Energidistribution’s area. Resources could trade across all three regionnät areas through the abonnemangsväxling mechanism.

Products

Three product types operated simultaneously in season 3:

All products: 0.1 MW minimum bid, 0.01 MW granularity, 60-minute minimum uthållighet (endurance), all pay-as-bid, market closes T-2 (intraday).

ShortFlex Availability was new in season 3, replacing the previous VeckoFlex product. The innovation was that DSOs could now specify which hours availability was needed (announced 1–5 days ahead based on forecasts) rather than a fixed weekly schedule. This improved targeting and enabled FSPs to bid selectively by forecast. The guarantee: at least 160 availability hours per season (jointly guaranteed by Vattenfall and Ellevio).

Compensation structure: all three products use the same delivery tolerance model:

• ≥80% delivery: 100% payment
• 40–80% delivery: linear reduction (2.5% per 1% below 80%)
• ≤40% delivery: 0% payment

For LongFlex, this is assessed per-month (average delivery). For ShortFlex and ShortFlex Availability, per activation hour.

Market architecture: abonnemangsväxling

The unique feature of sthlmflex was abonnemangsväxling (subscription switching) — enabling flexibility resources in any of the three Stockholm regional areas to benefit any buying DSO:

• When Vattenfall Norra bought flex from a resource in Ellevio’s area, Ellevio received a reduced subscription from Svk; Vattenfall Norra’s subscription was increased proportionally — on an hour-by-hour basis
• Financial settlement handled by NODES (market operator)
• Subscription management (actual subscription levels) handled by Svenska kraftnät
• A three-party agreement between Svk, Vattenfall, and Ellevio enabled the guaranteed version: Vattenfall Norra could request subscription switching via Svk directly
• E.ON’s lokalnät participation was outside the abonnemangsväxling mechanism — E.ON participated in the market but cross-area subscription transfers did not apply at the lokalnät level

The SWITCH flex tool (“flexverktyget”) handled: subscription application management (tillfälligt abonnemang, dispenser), abonnemangsnivå, uttagstak (capacity cap), day-ahead load forecasting, and dispatch workflow for all three buying DSOs.

Market time coordination

Baseline methods

Three options available to FSPs:

1. NODES standard method: 5-day rolling average of the same hour on preceding working days (NODES provides the calculation, requires NODES access to metering data)
2. FSP-provided baseline: FSP calculates and uploads; must be objective, transparent, and documentable; requires approval from buying DSO
3. Alternative agreement: e.g., for reserve power without separate meters; agreed case-by-case with the buying DSOs

Baseline must be submitted before bidding (at least the preceding calendar day). NODES validates delivery by comparing measured values against baseline for the delivery period.

FSPs can use either the grid operator’s metering data or their own sub-meters.

Load forecasting

Two ML-based forecasts used by DSOs (via SWITCH flex tool):

Inputs: historical load data, weather forecasts (SMHI), production plans from large grid customers, real-time grid state.

Accuracy (MAPE, winter 2022/23):

Performance improves significantly below −5°C (MAPE ~4.6% day-ahead vs ~5.5% average) — important since cold periods are exactly when congestion risk is highest. Forecast accuracy decreased during 12% of season hours due to abnormal weather data inputs and real-time SCADA data problems.

Key gap identified: energy prices were not included as an input variable, so the ML model could not learn the relationship between high prices and reduced load. This was a material problem in 2022/23, when high electricity prices led to substantial and unexpected load reduction throughout the season.

Market results: season 3 (2022/2023)

Participants: 9 FSPs, 4,639 prequalified resources, 3,897 pseudonyms registered in NODES (84%)

Why so low in S3: A combination of factors reduced demand for flex:

• Normal-to-warm winter (by 1991–2020 baseline); cold only in December 2022
• High electricity prices → Stockholm Exergi ran substantial local production in City area (~200–300 MW) → improved capacity situation significantly
• Svk’s operational state was normal → temporary subscriptions readily available at 244 kr/MWh (often cheaper than market flex)
• High energy prices → consumers reduced consumption → lower grid load

Prequalification

All resources must prequalify. FSPs declare: resource locations (per market area), products they will bid on, metering data source (own or grid operator). DSOs verify and register resources; FSPs receive anonymized pseudonyms for NODES registration.

Growth across seasons: prequalified resources grew from S1 → S2 → S3 (4,639 in S3). Forms were standardized in S3 to reduce administrative burden, but the process remained manual. The report identifies a target architecture: FSP registers information once, with coordinated registration between market operator and all relevant DSOs.

CIM standardization

sthlmflex commissioned DNV to standardize the information exchange interface based on IEC CIM (Common Information Model). Both NODES and E.ON Energidistribution (as IT platform providers) contributed. The work:

• Defined actors and roles based on the harmonized electricity market role model
• Defined business use cases and sequence diagrams for digital document exchanges
• Identified highest-frequency message types and mapped them to CIM ontology
• Produced a concept terminology list usable across all actors

Limitation: message profiles for the selected interfaces still need to be defined before the standard can be implemented. The work aligns with and will need adjustment for the forthcoming Network Code on Demand Response.

Energiföretagen has separately published an industry recommendation for communication between customers and grid companies, recommending OpenADR 3.0 as the communication protocol for villkorade avtal (conditional connection agreements).

FSP feedback and lessons

From the panel discussion at the February 2023 breakfast seminar (~70 in person, 100+ online):

Criticisms:

• Pricing tied to subscription cost creates an informal price ceiling on the market
• CAPEX bias (intäktsram): DSOs earn more from building new grid than from using existing grid efficiently — structural misalignment with flex market use
• Market viewed primarily as an R&D experiment rather than operational infrastructure

Valued features:

• Direct communication access to project team for problem resolution
• Availability payments (essential incentive in low-activation-frequency markets)
• Simplicity and low entry barriers

Industry recommendations:

1. National harmonization of product parameters (not necessarily identical, but comparable)
2. Technical standardization for interoperability (especially for FSPs active across multiple DSO areas)
3. Digitalization of prequalification: one-time registration, coordinated between market operator and all DSOs
4. Load forecasts must incorporate energy prices as an input variable

Key claims for wiki

• The “verktyg” (tool) described as developed by E.ON = SWITCH flex tool (Section 2.3.1: “Flexverktyget har även hanterat ansökan om tillfälligt abonnemang och dispens, samt abonnemangsnivå och uttagstak”)
• NODES was the market platform (bid management, clearing, settlement, baseline)
• sthlmflex had a unique TSO-DSO cross-subscription mechanism (abonnemangsväxling) not present in CoordiNet or E.ON’s markets
• ShortFlex Availability (S3) replaced VeckoFlex (S2 name, same concept)
• E.ON Energidistribution joined in S3 but only at lokalnät level; abonnemangsväxling did not apply
• The 244 kr/MWh price for temporary subscriptions functioned as a de facto market price ceiling throughout the project

Related pages

• SWITCH — the E.ON-developed flex tool used by sthlmflex’s DSO operators
• NODES — the market platform used by sthlmflex
• Flexibility Market — sthlmflex as part of Swedish market landscape
• CoordiNet — predecessor project that produced the SWITCH platform
• Aggregation — FSP and prequalification details
• Balancing Markets — mFRR forwarding tested in season 3
• Network Code on Demand Response — the regulation context expected to succeed sthlmflex
• Villkorade Avtal — OpenADR recommendation; coordination with market procurement