By now, you’ve probably heard of the upcoming total solar eclipse that will darken skies across the United States on August 21, 2017. The rare phenomenon is set to attract scores of visitors to those states with a front-row view. At this moment, states are putting the final touches on their plans to prepare for the influx of tourists.
But it’s not just the tourism industry that has had to steel itself for the solar spectacle. The eclipse poses a challenge to the United States’ burgeoning solar industry, which has greatly expanded since the last total eclipse to pass over the country in 1979.
What Happens to Solar Power in an Eclipse?
According to the Federal Energy Information Administration, the eclipse will significantly diminish the capacity of about 1,900 utility-scale solar plants and thousands of small-scale units across the country.
During the eclipse, the moon will pass in front of the sun, obscuring its rays completely in the direct path and partially in the areas beyond. This will partly or entirely cut off power to solar plants for several hours in the affected states.
The impact will be especially significant in California, which is the leading solar market in the United States. California is responsible for almost half the country’s total solar capacity, and 4.8 million homes in the state are powered by large and small scale solar facilities.
The California Independent System Operator, or CAISO, has been preparing for the eclipse for years. According to spokesperson Steven Greenlee, the greatest challenge will be managing the sharp changes in energy output that will occur during and after the eclipse.
Solar generation is always subject to variation. The output increases on sunny days and falls when it’s cloudy. It can change day-to-day and throughout the same day. However, the eclipse will cause a far more rapid decline than you’d see on a cloudy day, and it will rebound much quicker once the event is over. This is something solar grid operators will have to manage.
How Germany Coped with a Solar Eclipse
Fortunately, this isn’t the first time a major solar market has had to deal with an eclipse. In 2015, a total solar eclipse passed over Europe, cutting off 80% of the sunlight to Germany. Since Germany relies on solar energy for 40% of its electricity, this could have been a serious problem for the country’s energy grid.
But thanks to good planning and cooperation, Germany saw no major disturbances due to the eclipse.
Unlike weather events, solar eclipses can be predicted many, many years in advance. This means solar producers have plenty of opportunity to prepare.
To make up for the loss in solar-powered electricity, Germany ramped up its fossil fuel, nuclear, and hydro power output during the event. It also asked some of its biggest energy consumers to dial down their consumption temporarily.
American solar producers are following their example. The California Public Utilities Commission is encouraging people to reduce their usage during 9:30 and 11:30AM on August 21, and the state plans to fall back on hydro and natural gas power to stabilize the grid.
The solar eclipse will be a test for the country’s growing solar power industry, but if all goes as planned, it should have only a minor impact on peoples’ day to day lives. And if issues do arise, it will serve as a valuable lesson for solar producers.