Recognizing that rising energy tariffs have become an integral part of life, users’ understanding has undergone a revolution. Solar panels for homes are no longer seen as a prospect appearing on the horizon of a distant future. Stations for personal use and sale of excess are being installed today. However, the seasonal peculiarities of equipment operation still remain in the background. In this article, we will discuss how solar panels operate during the winter period.
Misleading News
Analyzing information about the development of solar energy in the world leads to the thought that stations are installed exclusively in deserts. Apart from the most famous Topaz Solar Star (579 MW) and Desert Sunlight Solar Farm (~550 MW), located in arid California (USA), solar farms are growing in other countries:
- Mexico (Villanueva Solar Park at 754 MW, Villanueva 1 at 427 MW and Villanueva 3 at 327 MW).
- China (impressive Great Wall of Solar in the Tengger desert at 1500 MW, about 130 GW in total across the country).
- Egypt (Benban complex is under construction with an estimated power of 2 GW).
However, deserts are not the only places on the planet for converting solar energy. Moreover, for a set of solar panels, excessive surface heating creates problems, reducing the efficiency of the panels. Ideal conditions for generation turn out to be bright light and low temperatures. Of course, with dense cloud cover, the system will produce less energy, but correct calculation will allow dealing with such difficulties. A normally functioning scheme almost always charges the battery during the day.
Position of the Sun and Panel Tilt Level
Compared to the summer months, in the winter period in the temperate zone, the sun rises lower above the horizon line. Due to the angle of inclination of the earth’s axis, the day becomes shorter, and its duration is not enough to provide the station with energy. This natural factor can be partially compensated by orienting solar panels depending on the position and height of the sun’s rise.
If this is not done, you will have to put up with a loss of productivity. Solar panels on any number of kW in winter reduce productivity by 2-8 times (the drop depends on the region). It is clear that the further south the panels are installed, the higher the productivity will be in the winter period.
How Productivity Will Change
For the middle band, calculations show the following: solar panels facing south and giving about 300 kW⋅h at the peak of summer months, in the middle of winter will be able to generate no more than 60 kW⋅h, that is, 5 times less. The level was counted on a clean surface, free from snow. To clarify the level of energy generation, you can use a calculator. Moving along the arrow, the system helps to calculate the amount of energy produced, taking into account the heating of the panels, pollution, losses in conducting cables by months.
This means that even in the winter months, solar panels can still generate a significant amount of energy, although less than in the peak summer months. This is due to the shorter daylight hours and the lower position of the sun in the sky during winter. However, with proper planning and installation, solar panels can still be a viable source of energy during the winter months.
Hot Water Supply Situation
Those who have decided to buy solar panels are probably interested in whether it will be possible to heat water in winter. In the cold period, it is possible to get 25% of the energy needed for hot water supply. It is important to understand that losses occur not only due to a decrease in the amount of sunlight, heat goes through the storage tank and the circuit through which hot water moves. On average, at -30 0C outside, water with the help of a solar station can be heated to +10+15 0C, higher temperatures are raised by other heating systems.
If it is planned to use energy to heat water in a year-round mode, the reservoir-accumulator must be placed in the house. In this case, it will be possible to significantly reduce heat losses.
How to Optimize Station Operation
In the cold period of the year, the angle of inclination needs to be increased. The dependence was studied experimentally on control panels installed at a latitude of 53 degrees in the northern hemisphere.
In warm months, the most optimal angles turned out to be:
- April: 45
- May: 18
- June: 18
- July: 18
- August: 27
- September: 53
For the cold period:
- October: 53
- November: 90
- December: 90
- January: 90
- February: 53
- March: 53
In real conditions, you can either set one angle for the entire period or change the tilt twice a year at the autumn and spring equinox.
The given data with a small error can be adapted for Kiev (50°27′). On average, the optimal tilt of the panels corresponds to the latitude of the area. Such a position will ensure effective generation throughout the year.
When choosing which solar panels to buy, you need to pay attention not only to the generating equipment but also to the mounting structures. There are systems that can vary the tilt within certain limits.
How Snow Affects Energy Generation
Snow stuck on the panels cannot harm the system itself. The snow load is significantly lower than the calculated one, so the station will not be damaged by pressure. However, the snow cover affects productivity. To ensure generation, it is necessary to provide access to sunlight.
If the panels are installed at an angle, most likely, the area will be cleared under the action of gravity. The process can be accelerated by carefully removing snow with brushes in such a way as not to damage the panel itself.
Please note! In the winter period, clear weather contributes to the generation of energy, as solar panels are not affected by high temperatures. Under ideal conditions with complete absence of cloudiness, more energy is generated in 1 hour in January than in the same time in July. Of course, the total generation in winter will be lower, as there will not be enough daylight.
While the capabilities of stations are not enough to fully provide hot water supply and heating, but the amount produced in any case will reduce user costs and help return investments within 7-10 years. If you use panels only for electricity production, the cost of solar panels pays off in 3-5 years.