The bright side of cold weather: solar panels efficiency
In Spain, the electric bill in January increased by 18.4% due to the fact that renewable energies stopped generating electricity momentarily because of snow storms. Although many used this argument to blame renewable energies and pinpoint the disadvantages of variable generation flows, others saw the contrary. If there weren’t renewable energies, our electric bills would be a lot higher. In fact, Teresa Ribera, Minister for the Ecological Transition of Spain has predicted that by 2022 and 2023, due to the massive entry of renewables into the system, the prices of the Spanish energy market could be below other traditionally cheaper ones, “such as German or French markets”.
Although energy prices reached record levels on the 8th of January (average 94,99 MWh), the average price collapsed by the end of the month to 1,42 MWh on the 31st due to strong winds.
Overall, in January, and according to data estimated by Red Eléctrica de España (REE), energy generation from renewable energy sources represented 52.3% of production, 34.9% more than the same period of 2020.
Here is where things get interesting, did you know that solar panels are more efficient the colder it gets? Why do you think that floating pv and bifacial modules are such an important trend? The sector demands efficiency, and cold weather has a direct impact.
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Contrary to what some may think, heat actually diminishes solar panel electricity production. Research has demonstrated that, although it may seem counter-intuitive, solar panel efficiency is affected negatively by temperature increases. Photovoltaic modules are tested at a temperature of 25 degrees, and depending on their installed location, heat can reduce output efficiency by 10-25%. As the temperature of the solar panel increases, its output current increases exponentially, while the voltage output is reduced linearly. In fact, the voltage reduction is so predictable, that it can be used to accurately measure temperature.
So how does the cold really affect solar modules? Let’s dive into pros and cons.
Colder temperatures enhance energy production efficiency, increasing the daily amount of electricity produced despite fewer daylight hours.
Solar panels create electricity from the sun’s light not the sun’s heat. This concept is drawn from the misunderstanding that the hotter it gets the better. In reality, the best case scenario in terms of panel efficiency would be a bright and cold day.
Sunlight can still navigate to the solar panels through lighter snow cover and maintain energy production.
Bifacial modules will get a boost in efficiency after a snow storm. If we add snow to the usual increase in performance due to the albedo effect on bifacial modules, these panels seem the optimal choice for areas with regular ice, snow or hail.
Solar panels are installed at an angle which allows most snow to slide off.
Furthermore, if the solar plant has single-axis structures with monitoring and remote systems, in the event of snowfall, the personnel may choose to place the panels in certain positions that allow the snow to fall.
The dark surface of the cells tends to attract more heat that causes a thaw of the surface and generates a probable sliding at 30º inclination, the usual in Spain. This can lead to a more cleaned and brilliant surface of the panels once the snow has slipped.
Many cities and states in northern regions with cold climates are instituting very favorable incentives for installing solar.
Additionally, wind also helps solar panels produce more voltage at lower temperatures. Wind chill lowers ambient temperatures. The chilling effect from wind carries away heat and enables panels to perform better. Another reason solar panels work better in wind is there are often fewer lingering clouds.
A light dusting of snow will not cause any significant disruptions as the sun’s UV rays can still penetrate through a small amount of snow until the wind clears off the panels. However, if too much snow builds up due to heavier snow falls, the production level may decrease or even cease.
It is common that if part of the module is covered and unable to produce energy, the whole panel will stop generating electricity.
The angle of panels may need adjustment to a higher angle in winter to capture more light, this angle might have a negative impact for snow to slide off on its own.
The amount of electricity generated during winter is less dependable than the summer due to extreme weather conditions or less sunlight hours.
It’s important to install extra durable solar panels rated to handle the weight loads from heavy snow and with no frames for the snow to slide off. This may increase cost.
You may need to incur extra costs on maintenance and personnel for clearing heavy snow if it is completely covering the panels and blocking transmission of all sunlight.
Overall, there are important aspects that affect efficiency all year round. However, looking into how cold affects solar modules, we can clearly see a pattern. Unless there are extreme weather conditions, cold weather will have a positive impact on our solar installation, especially on a ground-mounted scale.
If you are interested in knowing more about effects on your solar system design, with RatedPower you may simulate different weather conditions and study how exactly it affects your solar plants. Go ahead and take a free product tour.
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