Months of planning paid off for European transmission system operators (TSOs) with the management of Europe’s transmission grid during the March 20 solar eclipse.
A detailed analysis prior to the eclipse had found that up to 35GW of solar energy could fade and gradually be reinjected to the grid over a 2-hour period during the event. [Engerati-Solar Eclipse Challenges With High Levels of PV] In the event the drop was closer to some 17GW and the reintegration at 25GW, due to cloud cover over parts of the region and the post eclipse increased availability.
“Europeans are used to just pushing a button to switch the light on. They tend to forget all the highly technical and complex systems and tasks needed to maintain a constant balance between generation and demand on an interconnected power system,” said Pierre Bornard, deputy CEO of the French TSO RTE and chairman of the Board of the European Network for Transmission System Operators (ENTSO-E).
Germany and Italy solar generation impacted most
Germany and Italy faced the biggest challenges, with sunny conditions in Southern Germany and Northern Italy, where also the concentration of photovoltaics is the greatest of all the ENTSO-E area. The most critical period was the half-hour following the eclipse when the solar generation started to go up again.
In Germany, as a result of the very sunny weather the solar generation even exceeded the normal seasonal level. However, the German TSOs managed the high and fast variations of 39GW of installed solar generation smoothly, relying on power reserves at national and regional level. In view of the sunny weather forecast, Italy had decided in cooperation with DSOs and generators to take an equivalent of 5GW PV out of the system, reducing the level to 13GW, for the full duration of the eclipse. Reconnection was started only well after the eclipse was over after 14h00.
TSOs team up for eclipse
For the eclipse the TSOs had decided to double their staff in control rooms. They also had planned, as part of the extra preparatory work they carried out through ENTSO-E, that their control rooms would be in continuous communication throughout the morning to increase coordination and reduce reaction times.
An important role was also played by the TSOs’ Regional Security Coordination Initiatives (RCSIs). RSCIs, such as Coreso and TSC, were set up by European TSOs, deciding for coordinated answers to more variable power sources as well as more European energy market integration. In the case of the eclipse, the planning information on cross border electricity flows provided by RSCIs complemented the TSOs’ real time operation and allowed for a better coordination of actions, according to ENTSO-E.
Konstantin Staschus, secretary-general of ENTSO-E noted that many aspects of European electricity market integration are solved in the network codes that have been delivered by ENTSO-E. “It is urgent that we see a swift adoption of the network codes. So, with the network codes in place, when the next solar eclipse takes place in 2026, the management of such a challenging event will be much easier.”