Solar panels cannot receive constant sunlight all day. The sunlight can be obstructed by clouds, snow, rain, or shade from trees and buildings. What happens to your energy production when solar panels don’t receive sunlight during harsh weather conditions or due to shade? This article will answer that.
Direct Sunlight
Solar panels give their best performance in direct sunlight but can also operate without it. Usually, solar panels work with the input of direct and indirect sunlight. This is because whether sunlight is direct or indirect, it carries photons used by solar panels to produce electricity. Solar panels will use indirect sunlight for energy production even without direct sunlight. The only difference is that indirect sunlight will result in lower performance.
Solar Panels And Shade
Solar panels can operate in the shade but will produce less energy. The effect of shading on solar panels depends on the following factors:
Duration:
You will have a higher performance drop if your solar panels are under shade for longer. Just remember that shading and sunlight can never stay constant throughout the day, so they constantly fluctuate, leading to varied energy production.
Technology:
Modern solar panels also use half-cut cells, which decrease partial shade. However, traditional solar panels are very much affected by shade and have higher energy losses than half-cut cells.
Inverters:
With a central string inverter, even shade on a single panel decreases the power output for the entire solar array. On the other hand, systems with DC power optimizers or microinverters can have shade on an individual panel which won’t affect other panels. If your area has a lot of shade, it would be a good idea to install solar panels with half-cut cells connected to MLPEs to increase power output.
With constant heavy shade, you should consider if it’s even wise to install solar panels in the first place. You should talk to your professional solar installer to help calculate the power output and savings with the amount of shading on your roof to decide if installing solar panels is worth it.
Weather
Snow, rain, or clouds can decrease indirect and direct sunlight, resulting in lower solar power production.
Cloudy Days:
Clouds can block sunlight, impacting solar efficiency and output. With overcast conditions, you can expect the energy output to be anywhere from 10-60% of your normal energy production. The electricity production also depends upon the thickness of the cloud cover.
Rain:
Rain alone doesn’t impact energy output by a lot, but rain accompanied by heavy cloud cover does block the sun and darken the sky, which decreases power output by 40–90%. Precipitation can have little negative effects; however, there is a positive point too. If there is a lot of dirt or grime stuck on your solar panels or if you live in an area with a lot of dust, then a little rain will be beneficial in cleaning the panels and boosting your solar output.
Snow:
If the snow isn’t a huge burden on the solar panels, then they’ll be able to generate power even on snowy days. If the snow layer is light, sunlight can easily penetrate it and get to the solar panel. Solar panels thrive in coldness, preventing them from losing efficiency and overheating.
However, too much snow will block sunlight and greatly decrease solar output. This situation is rare since solar panels are installed at an angle that lets the snow slide off them. Also, since the solar panels are working, they will have a higher temperature than the snow, melting it. Melted snow is also great at cleaning solar panels since it’s basically water.
Beneficial Amount Of Sunlight
Your solar panels will be worthwhile if you get at least four peak sun hours daily. This is based on the calculation that 4000 watt-hours of total solar radiation per day equate to four peak hours. You shouldn’t only focus on the amount of sunlight when evaluating solar's cost-effectiveness. State incentives and local utility rates should also be considered when calculating your solar payback period. Savings increase with higher local utility rates and more local incentives.