How the August 21, 2017 Solar Eclipse will Affect Your Solar Panels

On Aug. 21, 2017, America will fall under the path of a total solar eclipse.

A total solar eclipse occurs when the disk of the moon appears to completely cover the disk of the sun in the sky. The fact that total solar eclipses occur at all is a quirk of cosmic geometry. The moon orbits an average of 239,000 miles (385,000 kilometers) from Earth — just the right distance to seem the same size in the sky as the much-larger sun. However, these heavenly bodies line up only about once every 18 months.

This Great American Total Solar Eclipse will darken skies all the way from Oregon to South Carolina, along a stretch of land about 70 miles (113 kilometers) wide.

US map solar eclipse

Outside the path of totality, skywatchers in the continental U.S. and other nearby areas will see a partial solar eclipse, in which the moon appears to take a bite out of the sun’s disk. Or you can view it live on the NASA website.

How will this effect my solar panels?

The upcoming solar eclipse will darken California skies from approximately 9:30 to 11:30 am PST, dimming solar radiation in Northern California by 76 percent. Unlike on a cloudy day, this loss will cause a rapid decline of electricity produced during the eclipse.

Here are some tips to save energy during the eclipse:

  • Wake up fully charged. Charge all cell phones, laptops and other electronics overnight so that they do not need to be plugged in during the eclipse.
  • Close window coverings to keep the house cool.
  • Pre-cool your home. Offset this drop in energy production by pre-cooling you homes before the eclipse. If you don’t own a programmable thermostat, you can manually adjust the temperature during the eclipse.
  • Wait to use appliances like dishwashers, washers and dryers until after the eclipse.

Go unplugged: 23% of the electricity used to power home electronics is consumed while the products are turned off (what we call “vampires”). The average U.S. household spends $100 per year to power devices while they are off or in standby mode. The morning of the eclipse, unplug things like coffee makers, TVs, computers, and gadgets that are always on (but not the refrigerator!)