Solar eclipses are expected to occur across much of Europe in March. This will be the first time that Europe has seen one for over 16 years. In 1999, when people stopped looking at the sun to get back to their daily lives, they caused a surge that still holds as a UK Record – greater even than a football game or royal wedding.
Solar power was only 0.1% of the electricity generated in Europe at that time. It has increased since then to at least 5%, as countries have subsidized renewables to reach EU targets. In continental Europe, the installed capacity of solar energy is expected to surpass 90 GW by this year. This is comparable to 150 coal-fired plants.
Regulators expect about 35 GW of solar energy to fade with the eclipse before it is injected back into Europe’s electric system.
This is a major test for solar energy. This is the first time that such an event can have a major impact on European nations with a lot of solar panels, such as Germany (44% of continental Europe’s installed capacity), Italy (with Spain and France), and France. The European grid integration could affect everyone.
The main concern of power utilities is to keep the grid stable throughout the eclipse. In what is called the European Synchronous Area, all of Europe’s electrical grids are connected. This allows countries to share excess energy to meet demand. Grid regulators must coordinate across regions in order to manage solar drop-off along with requests.
All of Europe’s superpowers in solar energy are part of one big grid. Wikimedia, CC BY-SA
According to EntSOE (Europe’s Association for National Grid Operators), around 50% of lost power will be from Germany and 21% from Italy. Grid will lose 0.4 GW/minute when the eclipse begins and gain 0.7 GW/minute once the sun returns.
It is an enormous amount of electricity to be generated at once. The European power system must adapt in real-time, and countries will help each other to maintain the scenario by providing coal, gas, and hydropower reserves.
Demand and supply must be carefully balanced in order for grids to function. Grids in continental Europe are connected to a single synchronous network. The normal operating frequency in Europe is 50 Hz. There are two legal limits: the upper limit of 50.5 Hz and the lower limit of 49.5 Hz. Generators will trip above the upper limit. Below the lower limit, demand will completely disconnect, which means that power will not reach the end users.
Keanu, don’t go below 50. 20th Century Fox
Imagine driving a car at a speed of 50 miles per hour (+/-0.5mph). The car’s dragging forces represent demand, while the accelerator represents generation. Maintaining the frequency at 50Hz ensures the safe operation of the system and the quality of the supply.
The most significant impact of the eclipse on the grid is not due to solar energy but rather human behavior. The Solar Power Portal graph shows that during the 1999 UK eclipse, many people took time off work to watch the event.
UK power consumption during the 1999 eclipse compared to the previous day. Solar Power Portal / National Grid
The 3-GW surge is greater than either the 2-GW spike after England beat Germany in the 1990 semi-final of the World Cup or the 24-GW end after the 2011 Royal Wedding.
This time around, we can expect something similar. Demand will drop before the maximum eclipse and increase after as people return inside to watch TV, light the kettle, and turn off the lights.
This could present a challenge as the system has to adapt to changing loads. It is important to plan because you cannot just increase the electricity production. Grid coordinators are prepared for electricity surges, which can occur from time to time. The 2014 World Cup is a good example.
The eclipse of the sun on Friday will serve as a test for future times when renewable energies such as solar and wind are expected to produce more electricity despite their volatility and spread. Solar power will be a major source of energy in Germany, Italy, and the US. Even cloudy weather can cause a significant drop in production.