Technicians prepare for impact of solar power loss on electricity grids as moon passes between solar panels and the sun but power supply unlikely to be affected

The loss of solar power generation during Friday’s eclipse will be an unprecedented test for the European grid but is very unlikely to cause problems for electricity users, according to electricity providers in the UK and Europe.

If the weather is clear on Friday morning the European grid will suddenly lose the equivalent generation of eight to ten very large coal power plants as the moon passes between solar panels and the sun. The loss of generation will occur over a much shorter period than it takes to get dark at night. The eclipse will cover about 85% of the sun from the centre of the viewing zone.

The event presents a serious challenge to a grid designed originally to carry consistent power supplied by large power stations. Technicians from the European Network of Transmission System Operators for Electricity (Entso-E) have been working for more than a year on how to cope with the potential loss of 35,000MW of generating capacity.

Forecasters are predicting largely cloudy weather for much of Europe, meaning the dip in power will be less pronounced than it would be in sunshine. But a spokeswoman for Entso-E said engineers were “very confident” the system would cope, even if conditions are sunny.

“The risk is serious but we are taking all measures to mitigate them. It is very unlikely there will be any incidents,” she said.

Facebook Twitter Pinterest Visualisation of the March 20 solar eclipse. Source: MeteoSwiss

The risk of an incident in the UK is much smaller than in continental Europe, where solar has a much larger share of electricity generation (3%). Even so, researchers from Oxford University said they will be watching the event closely.

Professor Alessandro Abate, an electrical engineer, said the solar eclipse would be an opportunity to observe what happens when a large section of the UK grid suddenly powered down – as in a power failure or when a major transmission line came down.

“Nothing is going to happen for multiple reasons. First of all only a small percentage of the electricity on the grid is generated by renewables here in the UK and further more the eclipse will only be partial,” he said.

“I’m certainly not saying there will be a catastrophic cascading of blackouts. This is not going to happen. 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.”

Abate said the next total eclipse over Europe will not be for 80 years, by which time the grid will have adapted to cope with the variability introduced by the surging renewable market.

A spokesperson for the UK National Grid was similarly certain that there was no danger of blackouts. “It’s the kind of event that we forecast for all the time and lots of other generation is available. The eclipse isn’t happening at peak time so we can comfortably make up the difference,” she said.

In the UK, more than half of the solar generation could be lost. But this will be largely offset by the drop in demand caused by people stopping what they are doing for a few minutes to wonder at the astronomical event. If it is cloudy, as currently forecast, then demand will increase but the drop in power, and thus the effect on the grid, will be negligible.

A spokeswoman for the European Photovoltaic Industry Association said the eclipse was a predictable event and therefore little risk to the security of the grid.

“In comparison a failure of a large power plant would be more difficult to address, as typically such events occur without warning. 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. If the weather is a bit cloudy, the eclipse will go unnoticed,” she said.