MARI and PICASSO
How control reserves on European markets keep the system stable in a cost-effective way
The power system in balance, at the lowest possible cost.
As control area manager, APG is responsible for keeping the grid frequency stable at 50 Hz. For this to succeed, power generation and consumption must be in balance at all times. Fluctuations in consumption or generation that deviate from the schedules (forecasts) must be balanced at short notice. To ensure this, APG procures control reserves through market-based tenders, which can be activated at short notice when necessary. The costs incurred for this must be passed on to groups of grid users or to those causing the deviations, either as part of the system service charge or the balancing energy. Together with European partners, APG has been striving for years to minimize these costs and has also recorded significant successes in this regard. Thanks to the existing co-operations, annual costs were reduced by around 80% to €40 million between 2014 and 2020.
Further innovations and market integration measures aim to reduce costs even further and increase overall welfare, while creating more flexible opportunities for market players to participate in the control reserve market:
- MARI (Manually Activated Reserves Initiative) is the implementation project for the European mFRR platform (Platform for Calling Manually Activated Control Reserve).
- PICASSO (Platform for the International Coordination of Automated Frequency Restoration and Stable System Operation) is the implementation project for the European aFRR platform (platform for the retrieval of automatically activated control reserve).
Primary, secondary and tertiary: three types of control reserve
Basically, three types of control reserve can be distinguished: Within a few seconds, frequency deviations can be automatically stabilized with the primary control reserve (Frequency Containment Reserve - FCR). This compensation is achieved through the interconnection of the primary control reserves throughout the entire continental European grid. In contrast, the secondary control reserve (Automatic Frequency Restoration Reserve - aFRR), which is used in the event of longer-lasting deviations, must be kept available in the respective control areas. In order to avoid a prolonged activation of the secondary control reserves, the tertiary control reserve (Manual Frequency Restoration Reserve - mFRR) is used within a quarter of an hour. It must also be kept available in the respective control areas.
The changes in market design, in particular the facilitation of market access for suppliers of control reserves (for example, the possibility of merging small players into virtual power plants) as well as the shortening of intervals towards daily auctions and 4h product time slices and the resulting increase in competition have led to significant cost reductions in recent years. These developments are to be continued on an international level, in the co-operation of European transmission system operators. The European Electricity Balancing Guideline adopted in 2017 describes the target system envisaged for this in the EU. The basic idea is that the more short-term trading is possible and the greater the number of co-operation partners in Europe, the lower the costs. Consequently, the markets for secondary and tertiary control energy, which are limited to control areas, are to be expanded to the European level and the auction intervals shortened to 15 minutes.
Successful start in 2022
At the European level, the aFRR platform PICASSO started its operation in June 2022 with the first TSOs, while the mFRR platform MARI did so in October 2022. APG joined PICASSO on June 22, 2022. In the first six months after APG joined, the Austrian export-import balance is positive. This means that domestic secondary control reserve providers generate more export revenues than import costs incurred by APG. However, the overall cost-reducing or welfare-enhancing effect cannot yet be clearly ascertained due to the sharp rise in electricity prices.