Solar Eclipse Affected Solar Panels Over 1000km Away

Solar Power During Solar Eclipse
This house in Saskatoon, SK was tracking the effects of the solar eclipse on it’s solar power output. Keep reading to see results! Photo cred.

On Aug 21st, 2017, much of the northern United States experienced what is called a total solar eclipse – an event where the moon blocks 100% of the sun’s light from reaching Earth’s surface.

And while few people actually noticed the loss in sunlight, solar panels all across North America were affected.

The U.S. Energy Information Administration recently published this article about how over 1,900 utility-scale solar photovoltaic (PV) power plants across the USA produced much less energy that day.

Solar Eclipse Sun Intensity Chart
The moon’s effect on the sunlight in Saskatoon, SK. At peak, 70.08% of the sun was covered representing a 75.78% drop in sunlight intensity.

But the extent of the eclipse extended far beyond U.S. borders, even way up here in Canada!

Saskatoon, SK is located over 1000km away from the complete darkness of the total eclipse but it still experienced a nearly 76% reduction in sunlight intensity (see image to right).

Fortunately, one of Saskatoon’s first owners of solar power, Brian Johnston, was tracking his energy output that day.

Brian has a 7.02Kw solar array installed on his roof. And with a blue and cloudless sky he expects to generate about 6,000 watts of power at any given time during the afternoon.

Solar Panels During Solar Eclipse
Notice how the largest decline in power production coincides perfectly with maximal sun coverage. It happened at 11:43am to be exact!

But as the output chart on the right shows, that wasn’t quite the case. During the peak of the eclipse Brian lost over 70% of his power production exactly as predicted!

While the eclipse was actually happening Brian had the live stream of NASA’s coverage of the eclipse open on his computer and his solar power tracking app,, open on his phone.

Here’s what he said about the experience:

“There wasn’t a cloud in the sky and a just prior to the eclipse starting you could feel the heat of the sun. But then it felt like it was cold out. It was like you couldn’t feel the sun’s warmth anymore, there was light shining on my skin but no heat. The colour of everything changed.

The last thing that I asked Brian about was his solar panels and why he was so interested in tracking his output that day. His reply sums up his curious attitude about all things solar:

“I was watching the output of panels the whole time. I waited all day to see what it was going to do. We know what a cloud can do to solar production but I didn’t know what a solid object almost 400 000 km away would do.”

NAIT (Edmonton, Alberta):

Here is an image of energy production at the experimental solar array for effects of snow on solar panels at NAIT in Edmonton, Alberta. You can see they they experience a similar decline in power production!

NAIT Total Solar Eclipse Solar Power 1


What did you feel during the eclipse? Were you thinking about solar power too? Let us know in the comments below!

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