The most common question we hear is, “Will solar really work for me in the Pacific Northwest?” The short answer is yes--traditionally cloudy areas around the world aren’t just experimenting with solar; they’re readily embracing it.
Germany gets about as much sunshine as Alaska but has installed enough solar to provide more than 10% of its total energy needs. Great Britain and Scandinavian countries are advancing their renewable energy portfolios with more and more solar. Closer to home, Portland was named one of the top 20 U.S. solar cities by installed solar capacity. “Cloudy” regions are proven matches for solar. Here’s how solar works across different weather conditions:
Clouds + Rain
In the Pacific Northwest we are blessed with rainy winters. Without them, we wouldn’t get to enjoy the lush green landscapes west of the Cascades. The rainy season also brings several months of persistent cloud cover.
However, just because the sun isn’t visible doesn’t mean it’s not shining. Have you ever spent a cloudy day outside only to get home and realize you’re sunburned? Then you’ve experienced solar irradiation firsthand. Of course, solar panels generate the most electricity on clear days with abundant sunshine. That being said, direct, unmitigated sunlight is not a prerequisite for your system to produce power. Instead, it is a factor that affects output. Solar panels will work under clear skies, thick clouds, torrential downpours, and even full moons.
The exact amount of solar production varies with cloud density. Photovoltaic panels can use direct or indirect sunlight to generate power, though they are most effective in direct sunlight. Solar panels will still work even when the light is reflected or partially blocked by clouds. What’s more, rainfall actually helps to keep your panels operating efficiently by washing away any dust or dirt.
Lastly, it’s important to remember that one cloudy or snowy day isn’t as important as the cumulative amount of sunshine over the full year. Especially if you live in an area with annual net metering, energy generated by your panels during sunny hours will offset energy that you use at night and other times when your system isn't operating at full capacity. The goal is to install enough solar in the summer to overproduce and acquire energy credits to roll over and help offset those less sunny wintry days.
East of the mountains we are fortunate to have upwards of 300 days of sunshine per year. We also get substantial snowfall. So what happens to solar panels in the snow? Not to worry! If there’s less than an inch of snow, enough light will stream through to heat up the panel and melt the snow.
If more than an inch of snow collects on your solar array, the panels won’t produce energy. But remember that these winter days have the least solar production hours anyway, so it isn’t worth risking your safety to clear the snow off your panels. They are engineered to support a significant amount of weight, in some cases far more than even your roof was made for. The risk to the panels is actually greater when someone takes a shovel to them. Also, given the panels are glass and are located in the sunniest part of your roof, the snow will slide off the array much faster than it will on your shingle roof. So hunker down, enjoy some hot cocoa, and rest assured knowing that your solar system will be back to producing energy soon enough.