The proof of removing snow from photovoltaic systems is that the panels are able to produce more electricity for your home or business. This means less power usage on the grid, which will save you money over time. Additionally, snow can create an insulation blanket around the panel because it reflects sunlight back onto them. The downside of removing snow is that it could be damaging to the panel’s circuitry if not done a correctly-a little bit of water could have a lot of potential for damage!
How high is the yield loss due to snow?
This can only be assessed precisely on a case-by-case basis; it depends on the weather situation. If a stable high-pressure situation with lots of sunshine sets in after the snowfall and the snow remains on the photovoltaic modules for a long time, there can be comparatively high yield losses. On average, however, the yield losses are rather low: In the months of December and January, a photovoltaic system delivers about 20-kilowatt hours per kilowatt of rated power, and about six times that amount in the summer months. A PV system with a rated output of five kilowatts thus supplies about 100-kilowatt hours of electricity in a winter month. If the system is covered in snow for half the month, the yield loss is 50-kilowatt hours.
Salesmen’s tricks of the trade
Salesmen of systems for snow removal like to calculate the profitability. For example, they compare the solar radiation at midday on a sunny summer day with that on a sunny winter day. In fact, this is about half as high in winter as in summer. It is often forgotten that the days are shorter in winter and that sunny day is less frequent than in summer. This puts things back into perspective. There are now countless data on yields in summer and winter. So there is absolutely no reason to fiddle with radiation values and use them to calculate any theoretical values.
Offered systems for snow removal
If clearing is required, a soft broom with a telescopic extension is probably the most sensible option. On the other hand, working with a normal broom on the roof in winter is unlikely to be a good idea. Other systems are not only expensive but also have their pitfalls. Also offered are systems that wash the snow from the photovoltaic modules with warm water. Here it becomes really expensive, also the energy balance of the procedure is not the best. Finally, it is also tried to use the solar modules as a heater to defrost the snow. Technically, this works quite well, the modules only need to have electricity flowing through them in the opposite direction to the normal operating direction. However, it should be carefully checked whether the manufacturer’s warranty conditions allow this type of use.
Low yield losses as a rule
Normally, the yield losses due to snow are so low that it is not necessary to clear the photovoltaic modules. The situation can be different if several unfavorable circumstances come together: The house is located in a snowy location with long periods of frost and the roof is very flat so that the snow does not slide off by itself. Then it may well be worthwhile to reach for the telescopic snow rake for solar panels.