Solar eclipse chance to test grid response, say European technicians

Friday morning’s solar eclipse will cause only minimal disruption to European power grids, scientists say, but will offer an unprecedented opportunity to better understand how grids react to sudden losses of power failure.

In the U.K., which will experience a partial eclipse of around 85%, it is expected that more than half of the 5.5 GW of installed solar PV capacity will be lost during the hour-long eclipse, but a spokesperson for the U.K. National Grid told the Guardian that there would be no danger of a blackout.

"It is the kind of event that we forecast for all the time and lots of other generation is available," said the spokesperson. "The eclipse isn’t happening at peak time so we can comfortably make up the difference."

Technicians working on the U.K. grid also anticipate that because many people will stop what they are doing to observe the astronomical event, power demand will fall by such a level to largely offset any solar shortfall. Equally, if the weather is overcast as expected, then the effect on the grid will also be negligible.

Europe-wide, the eclipse is expected to trigger a loss of power equivalent to eight-to-ten large coal power plants going down, for a period of between 60-90 minutes. The dip in power will be less marked due to the expected cloudy weather, but technicians from the European Network of Transmission System Operators for Electricity (Entso-E) have nevertheless taken all measures required to mitigate the risk.

"It is very unlikely there will be any incidents," said an Entso-E spokeswoman.

In fact, many technicians and scientists working with grid integration are excited by the chance to analyze just what impact – if any – the eclipse will have on the grid. "I’m certainly not saying there will be a catastrophic cascading of blackouts,” said Oxford University’s Professor Alessandro Abate. "The only thing that is going to happen is there will be a bit of a dimming in renewable production and we are interested in understanding this slight variation, these small oscillations, that will propagate over the grid."

The European Photovoltaic Industry Association said that because the time, location and duration of the eclipse is known in advance, grid operators have been able to duly prepare. "Everyday demand is more volatile than the solar eclipse and grid operators are able to keep the system running and have done so for almost a century."

In Italy, which has the highest rate of connected solar PV penetration in the world, transmission grid operator Terna will switch off large-scale PV plants over 100 kW for 24 hours in order to mitigate any effect their sudden power losses could have on the grid.

Germany, which has Europe’s largest portfolio of connected PV, has no such plans to do likewise, pv magazine understands.