Solar panels perform at their best on a clear sunny day with no cloud cover. This does not mean that the conditions are going to be favorable all the time.
Due to weather conditions like snow, solar panel performance can be significantly affected. In such conditions, solar panels produce their power from diffused solar radiation (radiation scattered by molecules in the atmosphere) as there is hardly any direct sunlight.
Especially in a scenario where many of the countries that are leading in PV installations such as USA, Germany, Japan and UK, experience snow in parts of the country, the effect of snow on solar panel performance has become a concerning issue.
To understand this better, let us consider the following questions.
How do solar panels perform during snowfall?
The amount of snowfall can have an adverse effect on solar panel performance. Solar panels can operate pretty well under light snowfall. But when there is heavy snowfall and an accumulation of snow, the solar panels are blocked and this can reduce solar panel output or even stop generation completely.
The more the amount of snow that is accumulated, the more the reduction in performance. But understand that even if this is the case, the snow does not remain on the roof for long even in the most snowy conditions.
Since solar panels are mostly placed at an angle, this can help the snow slide off. Ground mounted panels can be tilted to steeper angles to help snow slide off the surface.
How does snowfall help solar panels?
Often, due to the light reflections off the snow on the ground onto the solar panels, also called albedo effect, solar panel output is increased. Of course, this happens when there no snow cover over the solar panels. There have been reported cases of 100% output during snowy conditions and often generating more output than during summertime.
Moreover, the snow falling off the solar panels aids in cleaning the solar panel surface thereby providing a boost to the solar panel performance.
Dark solar panels that retain heat can accelerate melting of snow compared to normal roofs. Thin-film panels work better with diffused sunlight and hence can perform better in snowy conditions.
Are solar panels a good investment in snowy regions?
Yes, it is a good investment. It should be noted that winter is only one of the seasons and the worst of it can last for a maximum of 3 months. It is also important to note that in regions with heavy snowfall, the summers tend to be longer hence compensating for the production loss in winter.
All the above being said, as a general consensus, snowfall reduces performance of solar panels. That being said, it can vary by location. For example, UK climate is apt for solar installations as the weather is temperate and there is hardly any extreme snow conditions. But many parts of Scandinavia and the Swiss alps that experience heavy snow conditions may find it difficult to generate productive solar panel output over the year.
Please understand that the key factor when sizing your solar system is to consider the number of sunny days available over the entire year instead of a couple of snowy days that wouldn’t significant affect the overall performance.
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