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Distributed Power

Europe is Using So Much Solar Power that Today’s Eclipse Could Test its Grid

March 20, 2015
In several ancient cultures, the periodic dimming of the sun during daytime was thought to be the work of giant celestial beasts, who were devouring it. As humanity gained a better understanding of the natural world, people realized that the phenomenon was actually the moon harmlessly passing between the Earth and sun, and blocking light from reaching us. Fear of the solar eclipse turned into curiosity and pleasure.
But some of that fear briefly returned in recent months. Those afflicted with the terrors of yore were Europe’s power grid managers. Instead of imagined heavenly predators or bad omens, the dread was triggered by images of darkened photovoltaic cells. A partial eclipse that will have swept over much of Europe for more than four hours on Friday morning could be the first test for the continent’s alternative energy-infused electricity system.

Europe’s solar power installations now total around 90 gigawatts of capacity. Experts had predicted almost 34 gigawatts will gradually disappear from the system if Friday turns out to be a clear day.


Top: A lunar transit in front of the sun. Image credit: NASA. Above: People have been fascinated with eclipses for millennia. Above is an illustration of the moon blocking the sun from a 13th century manuscript. Image credit: The J. Paul Getty Museum

That still represents only a tiny fraction of total installed capacity on the continent. The concern wasn’t about not having enough power, it was about what would happen when that volume of electricity left the system and then came rushing back in as the eclipse ended.

“Managing this eventon the world’s largest interconnected grid is an unprecedented challenge for
European [transmission system operators],” officials
with the European Network of Transmission System Operators for Electricity
wrote in a report. “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…”

Determined not to fail nature’s test, power grid operators set to work planning for the eclipse
over the past year. Transmission system control rooms across Europe were tied
together through Internet-based interfaces to coordinate any steps they needed
to take to keep the system stable as solar power fluctuated. And, according to, power producers put more workers on duty and bolstered
their reserve capacity throughout the event to counter the potential for
blackouts. French authorities, for example, boosted reserve capacity from 1,000
megawatts to 1,700 MW.

Pierpaolo Mazza, the
general manager of GE’s Distributed Power business in the region, said his
customers have long realized that power sources like the sun come with a
different set of challenges from fossil fuels.

“Renewable energy
resources such as wind and sun have, without doubt, a low environmental impact,
but they are not always available,” he says. “With the accelerating growth of
renewable installations, a higher demand for fast-starting, flexible power
generation is required. Reliable energy supply, network stability and
increasing efficiency are playing an ever-increasing role.”

Components that add flexibility into
Europe’s electricity system, like flexible gas turbines that can ramp up fro
zero to 1,000 megawatts in 10 minutes and gas engines, will help keep the lights on.

That should keep blackouts at bay when the next big eclipse creeps in 2026.