One of the biggest questions asked about solar panels is how they function in bad weather, especially when snow falls and sits on top of the panel. Do they function at all? Do solar panels work with snow on them?
Solar panels will continue to produce electricity even if they have snow on them. If the snow accumulates on the panel and becomes thicker over time, it may block most of the sun’s radiant energy from reaching the PV cells and producing electricity.
Most solar PV systems will work fine in cold weather provided sunlight is still reaching them. Even though the output will be reduced, solar panels are made to handle mother nature – let’s see how!
Solar Panels Are Designed To Work In The Cold
Since many people around the USA live in areas that have snow during the winter, it would make sense that solar panels can function in those colder conditions. As strange as it may seem, solar panels generate more electricity and are more efficient in colder than hotter weather.
When the temperature rises above 77℉, the electrons inside the PV modules become ‘excited’, so they don’t operate with maximum efficiency as the voltage produced is lower and, as the temperature gets hotter, they become less and less effective.
While you might think that you’ll get the most generation from having panels in a hot sunny climate like Arizona, the reality is a little different. Where temperatures can average above 77℉ from March to September, solar panels will not be as effective.
Where the temperatures are more moderate, ranging from the upper 40’s to the low 70s, the efficiency of solar panels rises, and this is because they are electronic devices. Most electronic devices operate better when the temperatures are lower.
How Installation And Design Helps Clear Snow Off Solar Panels?
Another factor to consider is that the dark glass of the panels will heat up with the sun, and when snow falls on it, it will help melt the snow and allow it to clear off the surface faster.
Once any part of the panel is exposed to sunlight, it will absorb that heat, slowly radiate heat throughout the panel, and help to melt the snow off the surface to clear the panel. That single exposed piece of dark glass will gradually spread across the panel surface.
The mounting brackets on the solar panels angle the panel at between 30° and 45°, and this, coupled with the surface design, all help keep snow off the panel and keep it functioning.
Not only that, but the snow itself could add more light to the panels when it reflects sunlight off the ground and other snow-covered surfaces, which can increase the generation of electricity in the solar panels.
And one last benefit of snow – it helps to keep the panels clean!
During the summer, your panels may build up dirt and dust, and even rain may not remove it all, but a good snowfall can remove that layer and improve your panel’s efficiency!
How Does Snow Affect A Solar Panel?
A light layer of snow on the panels will marginally affect its ability to generate electricity. At the same time, if there is a snowstorm and the panels have a thick layer of snow on them, this will block out the sun and produce no electricity.
The snow’s water molecules help absorb and direct radiant energy from the sun, so light rain and snow don’t affect the panel’s capacity. Still, heavier rain or snow with lower clouds will reduce the panel’s capacity more.
Once the sun comes out after the snowstorm, the sun will melt the snow off the panels, and electricity production will resume. If the snow is heavy, then it may need some help from you. You could use a plastic roof rake to make some space under the panel for the snow to fall into.
Don’t use metal implements of any kind on your solar panels as if you damage them in the process; this will not be covered under your warranty.
The Optimal Generation Period For Solar Panels
Remember that the optimum period of solar generation in the USA is between the vernal equinoxes of March 21 and September 21. This is where your system will build up reserves for the real winter.
65% of all electricity is generated during this time, with only 35% generated between October and February, so if your panels do have some snow on them, you can wait until it melts and slides off, or wipe it away, but don’t risk injury or damage in months where your electrical production is down.
The only real weather that affects the ability of solar panels to generate electricity is very heavy cloud cover where little or no sunlight can penetrate through and reach the PV modules in the panels.
How Net Metering Can Save You In Winter
As more and more households and businesses across the USA install PV systems to reduce their energy costs, many will opt for the on-grid or grid-tied configuration. This is where you could ensure you have power even if the panels are covered in snow.
During the peak generation times, your PV system generates more than sufficient electricity, and the excess is fed back into the grid for use by the utility. Essentially, you sell the electricity you generate back to the wholesale supplier.
For every unit of electricity you supply, you get credit through a net metering system, and the more excess energy you supply to the grid, the more credit you get on your account.
So when the big snowstorms come and stop your panels from working for a few days, you have the connection to the grid to help you get by, and the best thing about it is, you won’t have to pay for it as it will offset against your utility credits!
Conclusion
We now know that snow doesn’t affect your solar panel’s ability to generate electricity, and heavy clouds that block the sun will do more to decrease production than snow will.
When your system is set up and installed properly, even the heaviest snowstorm will only temporarily affect production levels. Knowing that you will not be short of power in the dead of winter should be enough to keep you warm!