Swiss TSO-DSO partnership pilots DER coordination

Switzerland’s TSO Swissgrid and DSO ewz have piloted distributed energy resource (DER) coordination on the Equigy crowd balancing platform.

For the pilot, which was launched in Q2 of 2021, a rule-based transmission system operator (TSO)- distribution system operator (DSO) coordination approach was developed and implemented on the Equigy platform.

The concept and its implementation were then tested with a battery connected to the distribution grid of ewz

With ewz acting as the aggregator and controlling the battery, it was used to provide local congestion management services to ewz and tertiary reserve energy to Swissgrid, while respecting the distribution grid constraints.

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Effective coordination procedures between TSOs and DSOs are becoming increasingly important as growing numbers of DERs are connected to the power system, especially at the distribution level. There is a need for services, typically provided by third-party aggregators, by both.

The overall objective of the pilot was to develop a coordination approach to enable the efficient utilisation of DERs between TSOs and DSOs while bringing the greatest benefit to the security of the overall electricity system.

The blockchain-based Equigy platform, of which Swissgrid was one of the founder members with TenneT and Terna and subsequently joined by Austria’s APG and Germany’s TransnetBW, is being developed to facilitate the use of DERs for system ancillary services.

With the blockchain technology secure and transparent data exchange is ensured among the participants, i.e. TSOs, DSOs and aggregators, and it offers the possibility of largely automating the TSO-DSO coordination processes.

Key achievements announced of the project are the conceptualisation of a coordination mechanism accepted by both the Swiss TSO and a large Swiss DSO and aggregator, as well as the further development of the platform to support the TSO-DSO coordination approach.

The concept is based on a ‘traffic light model’ and defines all required data exchanges among the respective parties.

Important features noted of the concept are the consideration of distinct aggregator and DSO roles, even if taken over by the same entity as was done in this pilot, and the multi-purpose use of flexibility which allows aggregators to provide both TSO and DSO services through the same interface.

Furthermore, the concept allows DSOs to perform grid security analysis with their own tools outside the platform, thereby minimising the integration effort.