Does Solar Power Work on a Cloudy Day, at Night, or When There is Snow? 

September 4, 2019

As professional installers of solar energy systems, we hear quite a few questions like this one. Homeowners want to make sure that they are getting their money’s worth, so they worry about things like cloudy days, snow on the panels, or nighttime collection of energy. The answer is a little different for each case, so let’s break it down by scenario. 

On A Cloudy Day 

In short, solar energy systems DO work on days that are cloudy, partly cloudy, or even completely cloudy. The panels just do not perform as well as they would on a bright, sunny day. Just like if you go to the beach on a cloudy day, you can still get a sunburn. In fact, clouds can reflect or sometimes even magnify sunlight, which results in additional power output from your solar panels. Some of the top cities in our nation, including places like San Francisco, are not particularly sunny places but, rather, have high electric costs. San Fran’ thrives on solar power! The days of full sun, then, more than make up the difference in the cost of traditional electricity and solar power. 

At Night 

Since solar panels require sunlight to produce electricity, they do not work in darkness. Many of our clients wonder how they can use electricity if their solar panels are not collecting during the overnight hours. Remember that net metering allows you to access electricity during the darkness when the sun is no longer shining on your panels. Some areas also have solar storage technology that helps solve this problem. 

During Snow 

This is a great question, especially for states that see lots of snow during the winter months. New England is notorious for at least a few snowstorms that dump a few inches of snow during the winter. Believe it or not, snow and the cold temperatures associated with this type of climate can actually improve solar panel output. Snow has reflective characteristics that can help improve PV performance. The only concern with snow is the accumulation of it on the panels. Thankfully, direct sunlight usually melts the snow on the panels and they are installed at an angle that allows for the snow to slide off on its own. On occasion, owners do find that they need to brush off the snow. There are special solar panel snow rakes that can help on the rare occasion that this occurs. 

To wrap up, solar energy systems most certainly work at the highest efficiency when they are receiving direct sunlight. However, having some overcast days does not mean that your system isn’t working for you. Talk to your installer about the best location and how many days a year you can generally expect to be collecting solar energy. Most homes in New England still collect enough to reduce or eliminate the home’s electric bill. Contact BlueSel today at 781-281-8130, or visit our website