The Eclipse’s Interesting Effect on Solar Power in D.C.

This past Monday, millions of Americans stopped what they were doing to admire one of nature’s most incredible phenomenons – the solar eclipse.

The solar eclipse was an amazing event to witness. We were able to experience a partial eclipse here in Washington, DC and for one of our employees, the total eclipse was something she will remember forever.

“Totality was one of the most incredible experiences I’ve ever had. When the last speck of the sun disappeared, everything changed so dramatically. The world went dark, the temperature fell, and when I took off my glasses, the glowing ring in the sky was so much larger and clearer than I expected it to be. Everyone gasped and started cheering. It felt cosmic and otherworldly. When the spell was broken and the sun’s rays started peeking out from behind the moon, I was left stunned and humbled. It was one of those experiences that’s hard to describe and you can only really understand it if you’ve seen it. I sincerely hope everyone has the chance to experience totality at some point in their life.” – Angela G.

As excited as we were about the eclipse, we were just as interested to see how it would affect our community solar projects and their production. We are able to track the production of all of our projects in real-time, so we could watch the progression of the eclipse on our computer monitors (no special glasses needed).

This first chart shows the production of a solar system on a pretty normal, sunny day.  When looking at the chart, you can see that solar production increases as the sun rises and moves across the sky. The project’s production then starts to fall as the sun begins to set.

The second chart shows production from the same project but from a few days earlier. On this day, production was not as steady – possibly due to cloudy weather. Despite this, you can still see that production generally follows the same bell curve.

Now, this is where it gets interesting. The image below shows production from the same project as the charts above, but this report is from the day of the solar eclipse. In Washington DC, the moon started to eclipse the sun at 1:17 pm and it hit maximum coverage, blocking about 80% of the sun, around 2:42 pm. The large dip in production shows exactly when the moon was blocking part of the sun. As soon as the eclipse was over, solar production went back up to normal and then continued to fall as the sun set.  

Here is one more example from another solar project in Washington D.C.

Between 1:15 and 1:30 PM, the moon is just starting to cover the sun. This is right when production starts to decrease.

Around 2:42 PM, the moon was covering most of the sun and blocking solar rays from reaching our solar panels. This project was not in the path of totality so there was still some energy being produced at the height of the eclipse.

By 3:30 PM, the eclipse was over and production went right back up to where it would normally be in late afternoon.
Monday’s solar eclipse was just a small disruption to solar production across the country. PJM, the interconnection organization responsible for monitoring eastern parts of the grid, reported that so many Americans turned off their lights and left their desks to go outside that demand for electricity went down. Demand went down so much that the loss in solar production didn’t cause any issues.  

For now, we don’t have to worry about major disruptions to solar production, at least not until another eclipse captivates America in 2024.

Are you interested in tracking the production of your own remotely located solar panel? Check out Arcadia Power’s community solar program here, and start saving today!