Submetering

Submetering refers to the use of dedicated measuring devices (DMDs) installed behind the customer’s main grid connection point to measure individual circuits, loads, or appliances — such as an EV charger, heat pump, battery inverter, or industrial process — rather than total building consumption. Submetering is the measurement layer that makes individual distributed energy resources (DERs) visible, verifiable, and independently dispatchable in flexibility markets.

The measurement problem submetering solves

A DSO‘s smart meter at the connection point (“uttagspunkt” in Swedish) measures aggregate consumption and production for the whole building. When multiple DERs — an EV charger, a heat pump, and a rooftop battery — share that connection point, the meter cannot distinguish their individual contributions. From the meter’s perspective, all three together look like one fluctuating load.

This creates three problems for Flexibility markets:

1. Attribution failure: when an aggregator dispatches the EV charger for a flexibility event, it is impossible to verify from the whole-building meter how much the charger specifically contributed, as opposed to unrelated household consumption changes at the same time.

2. Baseline inaccuracy: baseline calculations — the counterfactual “what would we have consumed without activation” — are noisier when they include other building loads. A whole-building baseline is contaminated by independent load shifts in other appliances during the activation window.

3. Sub-threshold invisibility: a 7 kW EV charger in a commercial building consuming 500 kW is entirely invisible at the connection point. Without a DMD, it cannot be individually registered, verified, or compensated in a flexibility market.

EU regulatory basis — Art. 7b EMD Reform

The Electricity Market Design Reform Regulation (EU 2024/1747, Art. 7b) allows TSOs, DSOs and aggregators to use dedicated measuring devices (embedded in flexibility assets) for observability and settlement of flexibility services, even where smart meters are not installed (Source - Electricity Market Design Reform Regulation (EU 2024-1747)). Key provisions:

• Use of DMD data is subject to customer consent
• Member States establish DMD data validation requirements, including interoperability
• DMDs are an additional layer behind the connection point, not a replacement for the smart meter; the Comillas/BeFlexible paper stresses that submeter data should ultimately be consistent with the main meter at the connection point (Source - Submetering for Flexibility Services Comillas (2024))
• Implementation rules (technical standards, data format, access rights, cost recovery) remain pending at member-state level as of 2026 (wiki assessment)

This is significant because it formally recognises that the connection-point smart meter can be insufficient for the individual DER measurement that Aggregation and explicit Demand Response require at scale. See Electricity Market Design Reform 2024 for the broader package context.

The retail counterpart — multiple supply contracts (Art. 4)

Art. 7b gives submetering a role in explicit flexibility (verifying a dispatched DER). The amended Art. 4 of Directive 2019/944 gives it a second, commercial role in implicit flexibility: a customer may hold more than one supply contract simultaneously, using several metering or billing points behind a single connection point. Recital 19 of Directive 2024/1711 grounds this in advances in metering and sub-metering technology.

The Commission’s April 2026 retail report works the example through: EV charging on a dynamic or time-of-use contract, the heat pump on time-of-use or hybrid, and household base load on a conventional fixed contract. The point is to break the “all-or-nothing” choice that deters households from dynamic pricing — flexible loads see the price signal, the rest of consumption stays shielded. (Source - COM(2026)850 Retail Flexibility Report)

This makes the same physical measurement layer serve two distinct purposes: attribution of a dispatched flexibility event, and separation of a household’s supply into differently priced contracts. The technical requirements below are written for the former, which is the stricter case.

Settlement-grade vs indicative submetering

A wiki-level analytical distinction (not drawn in the Comillas/BeFlexible paper, which instead finds that almost all survey respondents want submeters held to the same requirements as smart meters, Source - Submetering for Flexibility Services Comillas (2024)):

Wiki hypothesis, unsourced: most flexibility verification may need only indicative-grade accuracy, with settlement-grade reserved for billing, and a regulator could therefore distinguish the two tiers when implementing the DMD provisions. The Comillas/BeFlexible survey points the other way (respondents want submeters held to the same requirements as smart meters), so this stays an open question, not a finding.

Technical requirements for flexibility-grade submetering

The Comillas/BeFlexible paper lists qualitative requirements only — it states no numeric sampling-rate, latency or protocol thresholds (Source - Submetering for Flexibility Services Comillas (2024)):

Submetering and baseline accuracy

The connection between submetering and Baseline Methods is direct: a DMD measuring a specific DER in isolation provides a clean, device-specific baseline that is not contaminated by other building loads.

Without submetering (whole-building baseline):

• Baseline includes all building loads — fluctuations in appliances, occupancy, weather response, and DER operation all appear as one combined signal
• Activation verification is approximate; disputes about actual delivery are common
• Particularly problematic for batteries (which cycle independently of building loads) and EV chargers (which have highly variable charging sessions)

With submetering (device-level baseline):

• Only the specific DER’s consumption/production is measured
• Activation delivery is unambiguous — the DMD records pre/post deviation for that device alone
• Battery gaming risk (MBMA manipulation via pre-activation charging/discharging) is isolated and can be detected

For multi-DER aggregated portfolios, submetering enables the per-DER attribution needed when different DER types should use different baseline methods (batteries → zero baseline; consumption loads → MBMA or rolling average).

Submetering and independent aggregation

Submetering is enabling infrastructure for independent aggregators. Without DMDs, an aggregator dispatching a DER in a multi-DER building cannot verify delivery independently — it depends entirely on the DSO’s whole-building meter data, creating potential data access friction.

With DMDs:

• The aggregator installs its own measurement at the DER level
• Verification is independent of the DSO’s AMI infrastructure
• The aggregator can confirm dispatch without waiting for DSO meter data
• Data ownership is clearer: the DMD data belongs to the customer (or aggregator with customer consent)

This also connects to the NC DR single-CU site registration concept: a DSO registers the whole site as one Controllable Unit at the connection-point meter; the aggregator then uses device-level DMD data to manage and verify individual DER dispatch within that site.

Swedish context

Swedish DSO pilots (for congestion management) are one of the few operational submetering uses the BeFlexible survey identified at DSO level, alongside Austria — most other Nordic activity the survey found is still pilot-stage on small loads. Key characteristics of the Swedish situation:

• Pilot use: a Swedish DSO in the BeFlexible survey reported submeters in use for DSO congestion management (alongside Austria), and the paper lists the Nordics as “in pilots” for small loads; it gives no further detail on who initiated them (Source - Submetering for Flexibility Services Comillas (2024))
• AMI reform context (wiki assessment): Sweden’s next-generation AMI is the infrastructure context within which submetering must fit; DMDs should complement the AMI rollout, not duplicate it
• Art. 7b implementation: as of 2026, Ei has not yet issued specific guidance on Art. 7b DMD rights in Sweden; the DHV/FIS architecture proposal (delivered September 2026; decision pending) may address how DMD data interacts with the central data infrastructure

The meter’s open interface vs the DMD right — these are distinct. The DSO smart meter has its own öppet kundgränssnitt (a standardised HAN-port-type interface giving near-real-time access to the connection-point mätvärden, required by förordning 1999:716 and the mätföreskrifterna EIFS 2025:1) — this is the meter reading itself, not a behind-the-meter device-level DMD. From 1 January 2027, Ei‘s EIFS 2026:8 (4 kap. 4 §) requires every DSO to publish, on its website/app, information about this interface and which dataprotokoll it supports, and to show on mina sidor whether the interface is active. The duty follows Ei’s spring-2025 riktad tillsyn, which found that missing dataprotokoll information was limiting consumer choice and undermining the open-interface requirement: third-party makers of realtidsmätare cannot build compatible products without knowing the supported protocol. Publishing the protocols rather than naming brands preserves DSO neutrality. EIFS 2026:8 does not address the Art. 7b device-level DMD right — so the öppet kundgränssnitt (meter, near-real-time read) and the Art. 7b DMD (behind-the-meter, settlement/indicative submetering) remain two separate layers; the gap below stands. (Source - EIFS 2026-8 Nätföretags Information till Elanvändare (2026))

The Network Code on Demand Response T&C development in Sweden (12-month window after NC DR entry into force) is where the practical rules for DMD use, data access, and baseline methodology will be established. The settlement-grade vs indicative distinction is directly relevant to how Ei and Svk define measurement requirements for NC DR service providers.

The Commission’s July 2026 proposal to amend the Electricity Regulation (COM(2026) 600) would add Art. 18b requiring smart metering systems for 50% of final customers by 31 December 2030 and 75% by 31 December 2033, with cost-benefit assessments applying only beyond 75%. Sweden already reports 100% smart-meter rollout (Source - ACER Retail Energy Markets Dashboard Sweden (2025)), so the proposal matters here chiefly as a marker of the EU direction on metering data for flexibility, not as a new Swedish obligation.

BeFlexible practitioner survey

The survey covered DSOs from Austria, Greece, the Netherlands, Italy (two), Spain (two) and Sweden, plus the Italian TSO and one retailer. DSO use of submetering is still limited: at DSO level submeters are used for congestion management in Austria and Sweden and for voltage control in Austria. Respondents disagreed about future use; they see most value in need forecasting, monitoring and activation, less in prequalification and bid collection, and least in settlement (only two DSOs). Almost all say submeters must meet the same requirements as smart meters, and the majority accept using the smart-meter data infrastructure. (Source - Submetering for Flexibility Services Comillas (2024))

Relationship to other concepts

• Aggregation — DMDs enable DER-level attribution for aggregated portfolios
• Baseline Methods — device-level baselines from DMDs improve accuracy and reduce gaming risk
• Demand Response — explicit DR requires verifiable delivery; submetering provides the measurement infrastructure
• Flexibility Communication Protocols — DMD data must be communicated to aggregator platforms and DSO systems in standard formats (CIM, DLMS/COSEM)
• Electricity Market Design Reform 2024 — Art. 7b is the EU legal basis
• Network Code on Demand Response — baseline and settlement framework will shape how DMDs are used in EU markets

Data gaps

• Swedish regulatory status of Art. 7b DMD right — has Ei issued guidance or included DMDs in the AMI reform process?
• Which Swedish DSO flexibility pilots use submetering, and for what specific application?
• How does the DHV/FIS architecture (report due September 2026) plan to handle DMD data flows?