Terna: solar eclipse safely managed

No impact on the national electricity system

TERNA: SOLAR ECLIPSE SAFELY MANAGED

Thanks to coordination with European network operators, the company has put in place

specific measures and enhanced monitoring in the National Control Centre

to ensure the continuity of the transmission service

Rome, 10 June 2021 - Terna safely managed and guaranteed the continuity of the national electricity service in real time during this morning's solar eclipse. The event affected most of northern Europe and, to a lesser extent, the northern regions of Italy. In order to deal with this natural phenomenon without repercussions to businesses and citizens, the Italian electricity grid operator had planned and implemented a series of countermeasures, after careful analysis carried out in close coordination with other European grid operators, that made it possible to limit the impact of the sudden drop in photovoltaic generation on the electricity system.

Specifically, the company headed by Stefano Donnarumma set up an enhanced monitoring system in the operations room at the NCC, the National Control Centre, where the company's highly qualified and specialised technicians manage the flow of electricity on the 74,000 km of high and extra-high voltage lines throughout Italy and the interconnections with foreign countries, 24 hours a day, 365 days a year. For the entire duration of the eclipse, Terna's NCC was in constant contact with the other control rooms of the European grid operators most affected, preparing and deploying, in synergy and coordination, all the necessary measures to ensure that the eclipse did not affect the Italian electricity system.

The astronomical phenomenon, which affected the planet's northern hemisphere and vast areas of northern Europe between 10:10 and 13:45, obscured up to 23% of the solar disk visible from our continent in the Nordic countries and only a small part - about 3.5% - of that observable from the northern regions of Italy between 11:35 and 13:03. The impact of the eclipse was greatest on photovoltaic production in France, the Netherlands, Germany and Belgium: overall it caused a reduction of maximum 4,9 GW of photovoltaic generation on the interconnected electricity system of continental Europe.

Although solar eclipses are a well-known phenomenon that can be predicted well in advance, they requires operational measures coordinated at European level and careful monitoring because of their potential impact on electricity systems, mainly due to the sudden drop in photovoltaic production. In fact, during an eclipse, the phenomenon of solar obscuration occurs faster than the time when the sun normally rises at dawn and sets at sunset, and therefore requires the adoption of shared and coordinated actions. In addition, it is important to consider the significant increase in the number of renewables installed in Europe in recent years, with photovoltaic energy actually doubling in a short time and currently standing at around 138 GW, compared to around 87 GW in 2015.

The coordination between all grid operators was fundamental to the safe management of continental Europe's interconnected electricity system, with dedicated task forces, preparatory measures and specific operational activities established within ENTSO-E (the association of European electricity transmission operators), ranging from the reinforcement of specialised technical personnel in the control rooms, to the preparation of ad hoc plans for the supply of dispatching services. The coordinated management of electricity grids across Europe - the largest interconnected grid in the world - during a natural phenomenon such as this also proved to be a further useful test in view of the next solar eclipse: according to current estimates, the one on 25 October 2022 will have a more significant impact.