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Smooth transition to AS4 protocol for electricity for [Stadtwerke Detmold]

Case Study – Market communication in the energy industry

Stadtwerke Detmold GmbH is an energy service provider that is based in the district town of Detmold, in the heart of the Lippe region in Germany, and employs around 180 people.

The customer

Stadtwerke Detmold supplies the region with electricity, natural gas, drinking water and district heating, and diligently pursues its goal of offering local residents climate-friendly, sustainable solutions at fair market prices.  Proximity to residents plays an important role – in addition to providing comprehensive online services, the company also gives everyone the opportunity of calling in at its customer centre in Detmold’s town centre to speak to someone in person.

The challenge

As a provider of electricity and gas, Stadtwerke Detmold is a participant in the German energy market, to which other electricity producers, electricity exchanges and network operators also belong. The communications between these parties are known as market communication, or MaKo for short. This market communication includes the transmission of meter readings, for example, as well as customer and supplier data. Previously, most of this communication was handled via email. 

Now, the legislator has revised the guidelines for exchanging electricity market data – to ensure more standardisation, better security for the exchange of data and information, and a higher level of reliability and interoperability: Since 1 April 2024, all MaKo messages relating to electricity must follow the Applicability Statement 4 (AS4) messaging protocol, which is a standardised method for exchanging documents and messages over the Internet: as a web service with digital signatures and encryption. Communications must also be secured by following BSI (Federal Office for Information Security) guidelines, using smart metering PKI (Public Key Infrastructure) certificates, and by complying with specific cryptographic requirements. This applies to the exchange of data regarding electricity supply to customers, market processes for electricity-generating market locations, data exchange processes in metering, and balancing group billing. Participants in the electricity market need a software and hardware solution to meet these requirements. 

The next stage will require gas providers to convert their market communications to AS4 by 1 April 2025. According to the official time schedule, these providers should already be prepared for the migration and have selected a suitable solution. By 30 September, they should have tested and implemented the solution. Up to 31 March 2025, both the old and new communication systems can operate in parallel, but communications must be switched completely to AS4 from 1 April 2025.

We are very happy with how quick and easy the conversion to the new AS4 protocol turned out to be and we will follow the same procedure for the gas market. achelos and Net at Work have proved to be ideal partner.

Richard Hilker, IT Administrator, Stadtwerke Detmold

Solution and result

With the support of its technical and specialist service providers, Stadtwerke Detmold was able to successfully implement the AS4 protocol for the electricity sector. As a system integrator, achelos GmbH worked in partnership with Net at Work GmbH to implement all the necessary hardware and software components. The AS4 gateway (NoSpamProxy AS4 Gateway) comes from Net at Work, and the hardware security module (HSM) was manufactured by Utimaco Management Services GmbH. The trio has already worked together on other projects – achelos is a platinum partner of Utimaco, and Utimaco uses NoSpamProxy to protect its own email communications from spam and viruses.

AS4 is based on the standards of electronic data interchange (EDI), which simplify the exchange of structured business documents with the help of standardised electronic formats such as EDIFACT (Electronic Data Interchange for Administration, Commerce and Transport). EDIFACT files are particularly important for the supply of electricity. At Stadtwerke Detmold, messages are converted to the new protocol via the NoSpamProxy email gateway: EDIFACT files can be sent via email, whereby NoSpamProxy converts them into AS4 messages and forwards them to the web service of the relevant communication partner. External partners can send AS4 messages to a NoSpamProxy endpoint, where the messages are then converted back into emails.

The software supplies the data exchange addresses of the market partners, the URL for calling up the AS4 web services, and the certificate with the public key. This makes communication simple and user-friendly. MaKo software administrators can manage the market partners, certificates and AS4 endpoints via a user interface, which means that market communications can operate without any additional intervention by email administrators or other members of the IT department.

The new guidelines include further requirements for participants in market communications with regard to data transmission. All messages sent must be signed and encrypted to prevent any unauthorised alterations and to prevent anyone else from reading them. It is essential that the cryptographic key and certificates required for this purpose are stored securely – Stadtwerke Detmold chose a hardware security module (HSM) to serve as the storage location. The HSM is connected to the email gateway. The HSM generates the keys and carries out the encryption procedures. An HSM is required for all active MaKo participants, i.e. participants who can control smart grid components and can switch transformers on and off. Although passive participants, including Stadtwerke Detmold, do not actively control components, the use of an HSM means that they are on the safe side. The rules and regulations require that the keys are securely stored and that random data generators certified by the BSI are used to create them. An HSM fulfils these requirements.

The project was successfully implemented within the specified timeline, so that Stadtwerke Detmold can now look back with satisfaction on the finished project. Since Stadtwerke Detmold was already using the NoSpamProxy email gateway to protect against malware and spam and to encrypt emails, minimum intervention in the network was required. On the software side, the only measures necessary for conversion to the AS4 protocol were an update of the NoSpamProxy and the installation of an add-on.

achelos implemented the HSM, established the connection to the software and trained the Stadtwerke team on how to use the new module. 

No changes to the existing infrastructure were necessary, and as far as the administrators and end customers were concerned, nothing changed. This is good news for energy suppliers who have not yet converted their MaKo to the new protocol: a simple solution is possible – it doesn’t need to be complicated. Electricity providers who have already carried out the procedure can profit from the preparatory work: Stadtwerke Detmold will apply the same solution for conversion to the protocol for the gas market – only minor adjustments will be necessary. 

Gas providers who have not yet gained any relevant experience will now have to hurry in order to meet the legally stipulated deadlines.