Is photovoltaics also economical in winter?
Even though it may seem like there is no sunshine in the winter, no one is really sitting in the dark. Therefore, there is undeniable light that fulfills the main requirement of a solar system, which is to produce electricity.
Photovoltaics in winter
It is well known that the output of a photovoltaic system decreases significantly in the winter months, but no solar system is only commissioned in the cold months before it is switched off again for the warmer seasons. Therefore, summer and winter are always considered together in the overall calculation of the yield (over the course of the year). But how reliable is the operation of photovoltaic systems when the sun is not there? Read more about it here.
Economic efficiency of PV systems in winter
Even in the middle of winter, when there is little to no sunshine, photovoltaics can be profitable. Because the days get shorter in the autumn and winter months, there are fewer hours of sunshine. As a result, the amount of energy that can be harvested from the solar system during the winter months is less. This is mainly because the sky is usually cloudy during the winter months. However, the yield of the photovoltaic system can be increased even without this component.
Why winter does not necessarily affect yields
If you want to run photovoltaic in winter, you should not look at the temperature, but rather upwards: If the sky is clear and blue, the PV system will produce a high solar yield in winter, no matter how cold it is outside. If the sky is cloudy and grey, the solar yield will be lower. When planning a photovoltaic system, one must consider its dimensions for the entire year.
Correct sizing of photovoltaic systems: This is how it works even in the winter months
If you are interested in buying a photovoltaic system, one of the first questions you have to answer is the dimensioning of the PV system. This determines the degree of self-sufficiency you want to achieve: Do you want to use as much of your own solar power as possible throughout the year, or are you looking for a reasonable middle ground? When the warmer summer months arrive, your PV system will produce a surplus of electricity by itself.
Thanks to the Renewable Energy Sources Act (EEG), every owner of a solar system now has the opportunity to feed the solar power generated by their system into the public grid and receive remuneration for it. This was not possible before the EEG came into force. However, if you take a closer look at the economics of photovoltaics, this is not a solution. Because the remuneration does not even come close to justifying the acquisition costs for such a dimensioned solar system.
How you can increase the yield of your solar system in winter
There are times when it is of utmost importance that the photovoltaic system maintains its peak output in winter. Alternatively, the size of the photovoltaic system can be increased so that sufficient solar power can also be generated in winter.
Is it possible to heat with photovoltaics in winter?
To answer your question: The electricity generated by your photovoltaic system can indeed be used to operate an electric heating system or a heat pump. However, it is usually not economical to operate the heat pump exclusively with electricity from the photovoltaic system. This is because the photovoltaic system would have to be very large and would produce much more electricity than is actually needed in the house. Solar energy can usually only provide about 10-15 percent of the total heating needs, but the value of each kilowatt hour it provides is significant. Solar energy, on the other hand, is an energy source that is completely renewable and helps to protect the environment.
With one kilowatt hour of electricity used by a heat pump, about four kilowatt hours of heat can be generated. Since the cost of solar electricity is 10 cents per kilowatt hour, the cost of a kilowatt hour of heat generated by a heat pump powered by photovoltaics is only 2.5 cents. Even though the high yields of a solar system are mainly due to the sunny spring and summer months, the high yields of a solar system in the autumn and winter months should not be underestimated. This amounts to about 30 percent of the total value for the year.
This means the following for those who operate solar power systems: During the winter months, a 10 kWp solar power system can still generate up to 3,620 kWh of energy from the sun. Depending on the conditions, things like leaves and light snow cover can cause your solar system to produce less energy. Therefore, you should make sure that the solar modules are kept free of leaves during the autumn and winter months.
Make perfect use of the sun’s rays even in winter
Even in the coldest months of the year, you can still use up to 35 percent of the energy generated by your solar system for your own needs. Storing electricity is especially important in the winter months. Since solar power production is lower in the winter, you should also consider purchasing a photovoltaic storage system. This allows you to temporarily store the solar energy produced during the day so that you can use it at a later time. The more solar power you use, the more money you will save.
So an electricity storage system can help you increase the amount of electricity you use yourself to as much as 80 percent, ultimately saving you money. This is particularly advantageous during the short winter days. The combination of a photovoltaic system with a solar storage system can lead to annual savings of up to 1,300 euros for a family with an annual consumption of 4,000 kWh of electricity. Not only have solar modules become cheaper in recent years, but so have other things. In addition, the price of electricity storage has fallen by more than forty percent over time. This means that the initial costs for solar storage units, which are usually equipped with lithium-ion batteries, usually pay for themselves just a few years after installation.
Effectiveness of photovoltaic systems at low temperatures
The effectiveness of a photovoltaic system is influenced by two different factors: The amount of solar energy received as incident radiation The temperature coefficient of the solar cells. It should come as no surprise that the amount of energy produced by the PV panels is directly proportional to the amount of sunlight that hits them. However, what many people don’t know is that efficiency increases as temperature increases. Because of the lower temperatures during the winter months, the efficiency of a photovoltaic system can reach its maximum potential. On winter days when the sun is shining, you can use the full potential of the solar system and effectively use the sun’s rays.
What is the optimal tilt angle and orientation for solar modules in winter?
The sun in summer looks very different from the sun in winter. The angle of incidence of the sun’s rays is almost vertical in the winter months. The sun is lower in the sky in the winter months than in the summer months. When the sun hits one of the solar modules of the system exactly, the system produces its maximum amount of electricity (at a right angle). For this reason, the optimal tilt angle is much steeper in the winter than in the summer. The formula for determining the optimal angle is as follows: 90 minus (90 minus latitude minus 23).
Use of a heat pump with photovoltaics
Combining a heat pump with other energy-saving measures is an excellent way to reduce dependence on conventional energy sources. To do this, you need to know that… The electricity consumption of heat pumps is usually quite high, especially in the colder months. A typical heat pump has a heating capacity of 10,000 kWh, and its annual energy consumption is between 2,000 and 4,000 kWh. A photovoltaic system with an output of 10 kWp generates only 1,400 kWh in the winter months.
It is important to remember that most of the time is spent heating the house when no electricity is being produced. In this case, the photovoltaic system can only cover about twenty percent of the total energy demand. Therefore, experts advise a system output of at least 12 kilowatts at the peak.