FRANKFURT, Feb 23 (Reuters) - European electricity grids are preparing for a solar eclipse on March 20, guarding against possible power supply glitches as the sun dwindles from view then rapidly returns to full force, they said on Monday.
A massive increase in solar power installations over the past decade could mean that transmission networks will have to cope with sharp drops and sudden surges in capacity.
“Solar eclipses have happened before but with the increase of installed photovoltaic energy generation, the risk of an incident could be serious without appropriate countermeasures,” European grid company lobby ENTSO-E said.
A total solar eclipse will only be visible in the remote north of Europe next month, but a partial eclipse will be seen over all of Europe, with astronomers predicting that sunlight will be cut by 30-98 percent depending on where you are.
Should the day be overcast, the eclipse would not have much impact on power supply, ENTSO-E said. But on a sunny day, it could cause major, rapid supply swings from photovoltaic panels, requiring adjustment action by grid managers to keep the system’s frequencies in balance.
Surplus power cannot be stored to large extents.
“Under a clear morning sky on 20 March 2015, some 35,000 megawatts of solar energy, which is the equivalent of nearly 80 medium size conventional generation units, will gradually fade from Europe’s electrical system before being gradually re-injected: all in the space of two hours,” ENTSO-E said.
Operators have already been making preparations for several months during the 2014/15 winter season, it said.
They have set up better communication amongst themselves and plan increased staff levels and special training.
Continental Europe overall has 87 GW of solar capacity, mainly in Germany, Italy and France.
German solar capacity alone has risen from just a few hundred MW in 2003, when the region last witnessed a major eclipse, to 38,200 MW now.
Under German renewable laws, solar power takes priority when being fed into the grid to reach consumers.
Germany’s four high-voltage power firms, in the heart of Europe, said separately they had commissioned studies on likely scenarios and were currently preparing for an 82 percent loss of sunshine between 0830 and 1100 GMT on the day.
“We plan to procure more reserve power and have started talking to reserve power providers,” their statement said. These can ramp up units at high speed and cost.
The four transmission system operators (TSOs) are utility EnBW’s TransnetBW, 50Hertz, the former grid unit of Vattenfall Europe, TenneT, formerly belonging to E.ON , and Amprion, which used to be owned by RWE .
Costs were not disclosed, but all grid expenses are charged to customers as part of final power bills. (Reporting by Vera Eckert, Additional reporting by Geert de Clercq, editing by Crispian Balmer)