Market communication: how meter readings become processes

What market communication is and where it came from

1,397 pages. That's the length of the application handbook for a single message, UTILMD for electricity, in version 2.2, binding since 1 October 2026^1,2. Each case in it, from a termination between suppliers to a master data change, has its own check identifier.

It isn't paperwork for its own sake. The Metering Point Operation Act (MsbG) requires metering and master data to flow in a uniform national format set by the Federal Network Agency³. The expert group EDI@Energy, led by the BDEW, writes the formats. Ruling chamber 6 consults on them and puts them into force by notice¹.

The current set-up goes back to a problem in 2018. The law wanted readings from intelligent metering systems (iMSys) to be processed in the device and sent from there, star-shaped, to everyone entitled to them. First-generation gateways couldn't do that. And the interim model of 2016, which routed readings through the grid operator, rested on a legal basis that expired at the end of 2019⁵.

On 20 December 2018 ruling chamber 6 settled the matter with its "MaKo 2020" ruling. From 1 December 2019 the metering point operator handles all readings and distributes them star-shaped, from its own IT system until suitable gateways exist⁵. Two years later BK6-20-160 brought "MaKo 2022", whose process documents applied from 1 October 2022⁶.

And the gateway as sender? The law still envisages it, but only once the BSI rates processing in the device as technically feasible and the Federal Network Agency bases a ruling on that⁷. Until then, star-shaped means: from the metering point operator's back end.

Four rulebooks, one of them dissolved

The processes sit in rulings with their own acronyms. The oldest is the GPKE, adopted on 11 July 2006 and in force since 1 August 2007⁸.

Sources for the table are ruling BK6-24-174, which amended all three rulebooks, and the handbooks^9,2,10,11,12.

The current GPKE has applied since 6 June 2025, parts 1 to 3 as amended by BK6-24-174 and part 4 as amended by BK6-22-024⁸. MPES disappeared the same day. Its rules for feed-in points now live in the GPKE¹³.

So a PV system runs through the same assignment processes as a household, with its own deadlines once direct marketing is involved¹¹. One rulebook fewer. Part 2 of the GPKE alone, though, runs to 115 pages¹¹.

MaKo 2026: messages, transport, web services

MaKo 2026 is an industry label. This year's formats rest on two notices from ruling chamber 6. The first put new versions into force on 1 April 2026¹⁴. The second has applied since 1 October 2026 and brings UTILMD electricity 2.2, MSCONS 3.2, UTILTS 1.1, APERAK 1.1 and a new AS4 profile, among others¹. Consultations happen twice a year¹⁵.

The main messages, briefly. UTILMD handles registrations and master data². MSCONS carries readings, from a single meter reading to a load profile, and for settlement also aggregated time series¹⁰. UTILTS transmits calculation formulas and the definitions of metering times, switching times and power curves¹⁶.

Every EDIFACT file gets a reply. Besides the AS4 delivery receipt, the recipient sends a CONTRL as a syntax check and, if the file can't be processed, an APERAK⁴. Two acknowledgements for one file.

Since 1 April 2024 these files have travelled only over AS4 in the electricity market. Ruling chamber 6 prescribed the web service standard on 31 March 2022, secured by the BSI's smart metering PKI. After a staged introduction from October 2023, e-mail and AS2 were allowed until 31 March 2024 at the latest¹⁷.

Web services exist for exactly two use cases. Since 6 June 2025 a supplier has queried the identifier of a market location, the MaLo ID, from the grid operator via web service¹¹. Grid operators and suppliers can also instruct or order control commands at the metering point operator via web service, where they can't send them to the metering system themselves. This applies to locations in the low-voltage grid with an iMSys and a control device¹². The specifications have since moved from Swagger to GitHub¹⁸. Anyone looking there will find a release 2.0.0 next to the production version. It was the subject of the consultations of February and July 2026 and isn't in force: notice no. 56 expressly left it out, and no new web API documents were published for 1 October 2026^1,19.

UTILTS stays

The current UTILTS handbook has a code for cases where the standard falls short. Z34: "calculation formula must be requested from the sender"¹⁶. If the formula that derives a market location's values from its measuring locations won't fit into the message, the grid operator sets this code and names a contact person. The formula then travels bilaterally, outside the standard.

The consultation of 31 July 2026 wanted to get rid of that, with web services instead of UTILTS. Several calculation formulas per location were to become possible, tranches included. Metering times, switching times and power curves were to move into the new structure, and location bundles would come via web service as well¹⁵.

Two months later the web services were off the table. The goal of carrying every formula within the standard was not.

Web services thus stay with MaLo ident and control, "expected until further notice". The two BDEW application guides of 18 August 2026, written to explain the planned web services, are coming off the MaKo platform¹⁹.

Why the U-turn? As with earlier releases, the comments were discussed with representatives of grid operators, grid users, the software industry and the Federal Network Agency. Which of them tipped the balance, the notice doesn't say¹⁹.

What's left for 1 April 2027? Not much. The ActivationDocument for redispatch 2.0 in version 1.1g becomes binding, along with the change history of the XML formats and version 1.11 of the transmission path rules, which mainly concern certificates for mTLS. An existing S/MIME certificate with the client authentication EKU can matter here too. There are no new EDIFACT documents, no new web API documents and no new decision trees on that date, and despite its subheading the notice says nothing of its own about the code lists¹⁹.

Switching supplier in 24 hours

"From 1 January 2026, the technical process of switching energy supplier must be completed within 24 hours and be possible on every working day." That's section 20a(2) of the Energy Industry Act (EnWG). Three sentences earlier sits the older limit, and it still applies: the switching procedure as a whole may not take longer than three weeks from the grid operator's receipt of the registration²⁰.

The Federal Network Agency built the processes in ruling BK6-22-024 of 21 March 2024. They've been live since 6 June 2025²¹.

The GPKE sets tight deadlines¹¹. The new supplier first queries the MaLo ID, and the grid operator has two hours to answer. Then the supplier registers, at the latest on the day before the last working day before supply starts. On the first working day after the registration, the clock runs. By 7 am the grid operator tells the new supplier about any existing assignment and asks the old supplier whether it will end it. By 9 am the answer has to be in, and silence counts as confirmation. By 11 am the grid operator assigns the new supplier or rejects the registration, and by noon it ends the old assignment.

The metering point operator gets the configurations to set up from the grid operator, by 5 pm on the working day before supply starts at the latest, and must have them in place by 10 pm. After that it delivers the readings to the new supplier¹².

Worked through as an example, a registration on Monday allows supply from Wednesday, midnight, at the earliest¹¹.

Three days from 10 to 80 percent. Fast, for an interface the whole market switches on at once. It wasn't over, though: after two weeks the association saw "clear instability in market data exchange", and the share of successful switches was still well below the average of the preceding months²².

The quarter hour instead of the profile

On 25 October 2020 the day had 100 quarter hours. The MSCONS handbook still uses that clock-change day as its example, and for the spring change it's 92¹⁰. Otherwise 96. A detail any software that processes load profiles has to get right.

Which market location is balanced by profile and which by measured quarter hours, the GPKE settles in three sentences⁴:

The last row needs two things. The gateway has to capture meter readings every quarter hour, which the law calls meter reading series measurement and the device world calls TAF 7, see chapter 4²³. And the metering point operator has to send the series daily for the previous day to the grid operator, the transmission system operator and the supplier⁷. In market communication that's an MSCONS with the load profile of the measuring or market location¹⁰.

The change came with ruling BK6-24-174 of 24 October 2024. Grid and metering point operators had to start preparing quarter-hour balancing for market locations fully equipped with iMSys no later than 1 December 2024⁹. Since 6 June 2025 their meter reading series have been sent throughout²¹.

Once every measuring location of a market location previously balanced by profile has an iMSys, the grid operator has to order quarter-hour balancing from the metering point operator¹². So the standard load profile doesn't end on a set date. It disappears meter by meter, at the pace of the rollout described in chapter 8.

For §14a this has consequences. When a grid operator steers a heat pump for grid purposes, it has to tell the supplier about every such intervention, and it does so through electronic market communication²⁴. How the command itself runs through gateway and control box is the subject of chapter 5. What quarter-hourly values mean for time-variable grid charges is covered in chapter 6.

The MaBiS hub

Since October 2024 ruling chamber 6 has been reworking balance group settlement. Procedure BK6-24-210 is to bundle the data at a central actor, the MaBiS hub, and make the processes compliant with data protection law by 2030 at the latest²⁵. In May 2025 the chamber split the procedure into two blocks, first meter value processing and pseudonymisation, later balancing and settlement^25,26.

The roles already exist in law, as meter value processor and aggregator²⁷. On formats, things have been clear since 1 October 2026: the hub stays with EDIFACT as well¹⁹.

The Federal Network Agency hasn't set a start date, and the ruling on the first block is still pending¹⁹. The timetable doing the rounds in the market is a BDEW proposal. The chamber put it out for consultation in September 2025 with its content unchanged and pointed out that it may still change²⁸.

Counterpoint: does the market need a central hub?

Ruling chamber 6 assumes that a central actor is the best way to reach its goals, including noticeable relief for market partners²⁵.

The VKU, the association of municipal companies, disagrees. In its position paper of 4 July 2025 it calls the hub model "by no means without alternative". The data protection argument doesn't convince it, since encrypted data transfer, segmented processing or temporary IDs could suffice. Distribution system operators would lose direct access to raw data while still carrying the financial risks, and checking the hub's results would take a kind of shadow balancing. A production system by 2028 strikes the VKU as "extremely ambitious"³⁰.

On pace, the associations aren't far apart. The BDEW wrote the scenario and calls it extremely demanding, while the VKU already finds the goal extremely ambitious^29,30.

On data protection the obligation is clear: the law explicitly requires pseudonymisation of load profiles and meter reading series in a whole range of transmissions³. The route there is open. On the timetable, data quality decides. A hub that needs almost all master data on day one won't start before the master data is ready.

Contracts and master data: the bottleneck

Since 1 July 2026, a breach of essential duties between grid operator and metering point operator can cost ten cents per day and per metering point affected^31,32. Little per case, but the total grows with every metering point and every day.

Ruling BK6-24-125 of 20 November 2025 revised the framework contract for metering point operators and set standard metering contracts for the first time, one with the connection user or connection owner (MSV-AN) and one with the supplier (MSV-LF)³². The metering contracts bind only the default metering point operator and cover modern metering devices and iMSys. The form under section 54 MsbG comes attached³³. The law asks for an easily understandable form listing who gets which data from whom, how often and for what purpose³⁴.

The link to market communication is section 4 of the framework contract, which refers to WiM and GPKE for processing. If one party fails to implement essential requirements from them, the other can claim the contractual penalty once the WiM and GPKE clearing processes have run³¹. A process description turns into a contract risk.

That leaves the part no ruling can solve alone. For the MaLo ID request the GPKE knows exactly one error case: the market location can't be identified, or not unambiguously. Supplier and customer then go into bilateral clearing¹¹. In UTILTS the same exit is called code Z34. In both cases the standard ends where the master data is wrong.

The MaBiS hub sharpens this. Notice no. 57 contained two steps explicitly meant to prepare for the hub: a grid location ID for every grid location, and a flat-rate measuring location for every flat-rate market location, so that each market location has at least one measuring location¹⁵. They aren't in an EDIFACT release for 1 April 2027, because there isn't one¹⁹. Working on your own data still pays off now.

Five checks for grid and metering point operators:

1. Measure the deadlines on the first working day

   Find out how many registrations your system answers by 11 am on the first working day and how many requests to the old supplier go out before 7 am. After 9 am, silence counts as confirmation.

2. Keep maintaining UTILTS

   No API project for calculation formulas. But expect changes to UTILMD and UTILTS: notice no. 58 announces them for a future consultation, without a date.

3. Clean up master data before the hub

   List the market locations for which you still send calculation formulas with code Z34, the flat-rate market locations without an assigned measuring location, and the grid locations kept without an ID. That list says more about your start in the MaBiS hub than any project plan.

4. Align contracts with BK6-24-125

   As default metering point operator you need MSV-AN and MSV-LF, form included. Settle who documents clearing cases before the first penalty arrives.

5. Check certificates for 1 April 2027

   From then on, the transmission path rules 1.11 apply to mTLS. Check whether your S/MIME certificate carries the client authentication EKU.