Power supplies affected by solar eclipse

  • An eclipse of the sun next month could disrupt Europe’s power supplies because so many countries now use solar energy, electricity system operators have warned.
  • “The risk of incident cannot be completely ruled out,” the European Network Transmission System Operators for Electricity said on Monday, adding the eclipse on March 20 would be “an unprecedented test for Europe’s electricity system”.
  • Countries with a large amount of solar power, such as Germany, are likely to be of most concern.



Solar eclipse puts Europe’s power supplies at risk

Solar power covered just 0.1 per cent of all the electricity produced in Europe from renewable energy sources around the time of the last large solar eclipse in Europe in 1999, but since then it has increased to at least 10.5 per cent, as countries subsidise green power to meet EU renewable energy targets.

The upcoming solar eclipse, which is due begin at 08:40 on March 20 and end at 12:50 Central European Time and should be visible across Europe. The eclipse will still be a “stress test” of the flexibility of the European power system, because it will have to adapt to a more abrupt shift in solar power generation than would normally occur, especially if it is a sunny day and all solar power stations were producing at full load.

Within 30 minutes the solar power production would decrease from 17.5 gigawatts to 6.2GW and then increase again up to 24.6GW. This means that within 30 minutes the system will have to adapt to a load change of -10GW to +15GW. This type of shift is expected to become more common by 2030 as more renewable energy comes on stream, so in a way March 20 is a glimpse into the future of our power systems.

Solar eclipses have occurred across Europe before, but the increase in solar power across the continent’s interconnected grids since 1999 means system operators are paying more attention to this one. It will have a cascading effect, as countries would draw on each other’s reserves of electricity in turn as the path of the eclipse cuts solar power at much faster rates than under natural conditions such as sunset or cloudy days. Coal, gas and hydropower generators are likely to be used to ensure balance in the system, which has to produce as much electricity as is used at all times. It’s definitely going to be a challenge for control rooms.

ENTSO-E, the European Network Transmission System Operators for Electricity, commented: “The solar eclipse is a perfect illustration that maintaining system security with more and more volatile and dispersed generation is becoming increasingly challenging. that makes this year’s solar eclipse so special is the fact that there is now a non-negligible amount of energy generation units connected to the grid that are highly sensitive to variations in solar radiation. This solar eclipse will thus be an unprecedented test for Europe’s electricity system, and useful to better understand the relationship between ambitious EU targets and the security of operation which all Europeans are very much depending on.”

Sources: Financial Times & ENTSO-E