How do Solar Panels Work in Shade or Bad Weather?
Solar-powered electricity generation has evolved into one of the most efficient, inexpensive, and accessible ways for people to reduce their carbon footprint. But as technology increases and solar panels become more and more popular, certain hesitations remain. Most of the questions revolve around a familiar topic: How do solar panels work?
Other common uncertainties about solar panels revolve around things like cloud cover and shade, reliability in extreme temperatures, and weather resiliency. Let’s look at why these factors should no longer be a concern when choosing solar panels.
Weather & Solar Panel Efficiency
Even though rooftop solar panels are often exposed to inclement outdoor weather conditions, they can withstand them.
On rainy or cloudy days, photovoltaic panels can produce anywhere between 10-25% of their optimal capacity. The exact amount will vary depending on how dark and heavy the rain and cloud cover is. But rain can help the performance of your solar panels by washing away any dirt, dust or pollen – very helpful!
Solar manufacturers have been reassuring customers for years that high winds will not damage their solar panels or the roof below them. In fact, according to CleanEnergyAuthority.com, solar manufacturers must obtain a certification that their panels can withstand up to 140 mile-per-hour winds, the equivalent of a Category 4 hurricane. If the roof underneath has been installed and maintained properly, there should be no problem.
Solar panels are electric devices and therefore, they are at risk for voltage surges caused by lightning. But your installer should make sure your system is properly grounded to prevent surges. Extra protection may be necessary, and a lightning protection system is a smart and easy upgrade.
“Will my solar panels work if there’s snow on my roof?” is a frequently asked question. Snow on solar panels is not a major problem. True, it can block the panels from receiving solar rays, but it usually melts off quickly because the panels are pointed directly at the sun.
The National Renewable Energy Laboratory (NREL), funded by SunShot (the U.S. Department of Energy’s initiative dedicated to improving the durability of solar modules), develops standardized industry-quality tests to assure that solar panels can survive the harsh environmental conditions to which they are directly exposed, including hail storms. Testing requires shooting ping-pong-ball-sized ice balls at PV modules in multiple places at about 70 miles per hour.
The testing also includes how the panels react to mechanical stress from: hail, being walked on, extreme high and low temperatures, humidity, solar ultraviolet radiation, and electrical stress the panels apply to themselves when operating in high-voltage situations.
Extreme Hot or Cold Temperatures
Solar panels work by absorbing the light from the sun — not the heat from the sun — and turning it into usable electricity. PV Semiconductors offer more resistance in extreme heat, making them less efficient when the modules should be most efficient. Thankfully, the amount of resistance is small, at most, reducing efficiency by about 10 percent. As for cold weather, solar panels will function normally as long as they are receiving the proper amount of sunlight.
Shaded Solar Panels
There’s no question that solar panels need the sun’s rays to generate electricity, therefore it is easy to assume that if the sun is not shining, you will be without power. But that’s not the case. Solar panel efficiency will be best in full, direct sunlight, but solar panels in cloudy weather or indirect sunlight will still function.
So how do we convert sunlight to electricity?
Solar panels produce energy with solar cells. Solar cells are small, square-shaped panel semiconductors made from silicon and other conductive materials manufactured in thin film layers. When sunlight strikes a solar cell, chemical reactions release electrons, generating electric current. The solar panel then converts those photons into electrons of direct current, which flow out of the solar panel and into an inverter and other electrical devices.
How and why does shade reduce solar panel efficiency?
Solar panels are composed of individual solar cells, and if those cells are covered by shade, then they will not work at 100% capacity. If a portion of your solar panels are covered, the other panels will still be operating as normal, but it will decrease the amount of electricity that the system produces overall.
Ways to Combat Shade’s Impact on Solar Panels
- Microinverters: Microinverters operate like Christmas lights. Even if one goes out, the rest will continue to stay lit. Solar panels with microinverters are best equipped to combat shade issues because each solar panel has an individual microinverter in it. If one panel is completely shaded, it will not have an impact on the others.
- Ground installed solar panels: When people think of solar panels, they typically assume they have to install them on their rooftop. But that is not your only option. A ground-mounted array allows you to have more control over how much sunlight your solar array receives because you can put it in direct sunlight. More benefits to installing ground-mounted solar panels can be found here.
Going Solar is a Smart Decision.
Every day, 173,000 terawatts of solar energy continuously reach the earth. That’s more than 10,000 times the world’s total daily energy use, making solar energy the world’s most abundant energy resource. The vast majority of the U.S. receives enough sunlight to make solar panels a very plausible option.
The consistent and predictable power, the environmental benefits, and the support you give your local utility are just some of the things that make solar power solution a smart decision.