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Efficient, reliable and at optimised cost

The new European platform MARI enables the exchange of fast tertiary control energy – without Switzerland for the time being

Yesterday, «MARI», the new, central European platform for the exchange of fast tertiary control energy, went into operation and the first European transmission system operators connected to the platform. As a founding member of the platform, Swissgrid has successfully completed all operational tests and is ready to participate. However, due to the political situation in the relationship between Switzerland and the EU and legal differences of opinion, Switzerland cannot be connected to the central MARI platform until further notice. Swissgrid has nevertheless implemented the necessary adaptation of the Swiss balancing energy market as planned to ensure that Switzerland is compatible with the new European platforms at least at the technical level.

With MARI, the «Manually Activated Reserves Initiative», Swissgrid and various members of the Association of European Network of Transmission System Operators for Electricity (ENSTO-E) have created a further platform for the cross-border exchange of control energy. The MARI platform enables the auctioning, billing, and monitoring of fast tertiary control energy (activation time of 12.5 minutes and delivery time of 15 minutes) within the European internal electricity market. The aim is to ensure more efficient procurement and more reliable provision of control energy at lower costs. The active participation of Swissgrid in MARI would help increase system security, as more control energy would be available than on the national market. It would also lead to lower costs for control energy. Above all, however, active participation by Swissgrid and Switzerland would result in better integration in the European interconnected grid.

Other control energy platforms

For Swissgrid, system security in Switzerland and thus in the European interconnected grid has top priority. Swissgrid therefore works closely with European partners to continuously develop and optimise grid operations. TERRE (Trans European Replacement Reserve Exchange), a European platform for the exchange of slow tertiary control energy (activation time of 30 minutes and delivery time of up to one hour), was put into operation in October 2020. PICASSO (Platform for the International Coordination of Automated Frequency Restoration and Stable System Operation), the European platform for the exchange of secondary control energy, also went into operation in June 2022. Although Swissgrid fulfils the technical requirements for both PICASSO and MARI, Switzerland has not yet been connected to the central platforms due to the political situation in the relationship between Switzerland and the EU and legal differences of opinion.

Threat of exclusion of Switzerland

According to EU Commission Regulation 2017/2195 establishing an Electricity Balancing Guideline (EB GL), Switzerland's participation in TERRE, MARI and PICASSO is only possible if an electricity agreement is in place or if the EU Commission agrees to Swissgrid's participation for reasons of system security. From the EU Commission’s perspective, Swissgrid’s participation breaches the Electricity Balancing Guideline (Art. 1.6 and 1.7 EB GL), as the EU Commission has not given its consent and, in its opinion, the preconditions for a positive decision are not in place. Swissgrid shares neither this legal opinion nor the technical assessment of the consequences of Swissgrid's non-participation. However, Swissgrid cannot currently force access to the platforms. For this reason, Switzerland has not yet been connected to PICASSO and MARI. Swissgrid is nevertheless committed to grid stability in Switzerland and Europe and therefore guarantees technical compatibility for the cross-border exchange of balancing energy.

What is control energy, and what is it used for?

Electricity demand can differ significantly depending on the time of day. In the grid control rooms in Aarau and Prilly, Swissgrid ensures 24/7 that the balance between generation and consumption is maintained and that reserves are available at all times to compensate for frequency fluctuations and imbalances in the Swiss control area. These reserves are held as control power in order to immediately stabilise the grid in the event of disturbances.

Control energy is the energy that a grid operator needs to balance unforeseen fluctuations in the grid. The grid frequency can fluctuate and be destabilised in both directions: if electricity consumption exceeds the supply, positive control energy is needed to establish equilibrium. This means that either more electricity needs to be quickly generated and fed into the grid, or electricity consumption needs to be reduced. Conversely, where supply is too high and demand for electricity is too low, negative control energy is used – electricity consumption is rapidly increased, or electricity generation needs to be reduced.

Three control energy qualities with different activation speeds are available to the transmission system operators. Primary control energy can be accessed within 30 seconds to rapidly stabilise the grid. If this fails to balance a frequency deviation, the central load frequency controller activates secondary control energy within five minutes. If primary and secondary control energy are not sufficient, tertiary control energy is available within 15 minutes.




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