Seen as a bad omen by old cultures, the solar eclipse last Friday was enough reason to make some people worrying. Germany, highly reliable on solar energy generation, faced a serious challenge. The country has around 37gigawatts installed photovoltaic capacity -a typical nuclear reactor is 1gigawatt. In a timespan of 75 minutes, solar power output of 21.7 gigawatts dropped to a low point of 6.2 gigawatts. When the eclipse was over its apec, the output increased again with 15 gigawatts, according to TenneT (one of the four transmission net operators in Germany) this is triple the usual rate. This effect was enlarged because the eclipse started in the morning when insolation (amount of sun rays falling on earth’s surface) was not so high, but ended around 11:30 AM when insolation is much higher. The whole effect was amplified because of the bright weather that day. Thanks to careful preparations, the German grid didn’t experience any problems. They put alternative power sources including coal, gas, biogas, nuclear and hydroelectric energy pumped from storage in action to fill in the gap. Some big industrial facilities such as aluminium plants, which are very energy intensive, temporarily lowered their demand. The solar eclipse was a unique test which is relevant for all of us, since we’re going towards more sustainable energy generation which make us more vulnerable to changes in nature. But there’s nothing to worry about -the German engineers have shown we can handle it.
The solar eclipse on March 20th posed a serious challenge to the German electricity grid (graph: Opower)
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