Partial solar eclipse and solar output

Maine photographer Mike Leonard drove to Illinois to capture the image above of the total eclipse today (August 21, 2017).  Here along the Maine coast we saw a partial (50-60%) eclipse.  It definitely got noticeably darker and cooler and impacted my solar power output.

The chart above came from my Weather Underground personal web page, there's a clear dip in solar Watts.

Looking at the past 5 days of the power output of my solar power system, you clearly see the correlation as the eclipse occurred today.

Zooming in it becomes even clearer.  Utilities that rely on large solar farms need to plan ahead for an eclipse by having their peaking generators on standby.  These are typically natural gas or hydro generators that are nimble enough to be able to ramp up their output rapidly.

I have a single 245W solar panel on the south wall of my house that also shows the power drop.

It was also interesting to feel the temperature drop.  The change was palpable when I was outside.

So that's how a solar energy geek experiences a solar eclipse!  The next full eclipse in the US will be on April 8, 2024 and we should get a nearly full eclipse in Maine.