Nothing is constant, the same for the seasons. Sometimes it freezing cold wether sometimes it’s scorching hot. With changing seasons, solar power generation and solar panel output also change. In this article, you’ll learn about solar panel output winter vs summer. Additionally, you also explore solar panel production by month.
Why Is Annual Energy Production Important?
Calculating the annual output before installing the solar power system for a residential, commercial, or industrial purpose is essential. It gives you an idea and a way to get the most out of it. You are aware of the difference in the ratio of energy production in different parts of the year. It is obvious that production is higher in summer than in winter. You need to factorize the solar output of all the seasons and not just particular days. Now, let’s start exploring solar panel output winter vs summer.
Solar Panel Output Winter Vs Summer
Solar production is not the same year-round. Seasonal changes affect the intensity of sunlight, which in turn leads to differentiated output by the solar power system. Your solar panels have been there for 25 years or more and during this period they face numerous seasons of rain, hail, and storm. All these things have the following effects on solar panels.
- Rainwater and storm dust slip off the panels due to the exterior glass layer. This way the panels are protected against surface heating.
- Direct lighting strikes can cause a sudden voltage surge which can damage the solar panels and other components.
- On a cloudy, rainy, and stormy day, the optimum power generation level is lower than usual.
Factors Influencing Solar Panel Output
These are the factors influencing a solar panel’s output-
1. Atmospheric Conditions
Winter means more cloudy days, rainy and snowy days. The sunlight exposure hours for the solar panels considerably reduce to a large extent. Thus, the amount of energy produced is also limited. You cannot rely completely on solar power systems for your power requirements during winter.
2. Condition of Solar Panels
These panels are continuously and constantly exposed to all weather conditions and other pollutants. This results in dirty and matted solar panels with low power generation. Regular cleaning and maintenance ensure that the surface is not covered with dust, snow, or water. For high power generation, you should at least clean the panels once every 1-2 months.
3. Landscape
It relates to the time of sunset at your location. If you live in an area surrounded by mountains, there will be shade hours before sunset because mountains are casting shadows over you. On the contrary, if you live in areas like California or in coastal cities you receive every last bit of sunlight irrespective of the season.
4. Location
Another determinant of solar panel output in winter vs summer is location. Annual sunshine received by solar panels depends on your location because different regions receive distinct sunshine. Solar insolation received by the panels varies too. The amount of solar energy falling on every centimeter square per minute is known as solar insolation.
Solar Panel Output Per Square Meter
4 Kilowatt is the common domestic solar panel system with 16 panels. The size of each panel is
1.6 square meters
Power Rating 265 watts (in ideal conditions)
Output per square meter = Number of panels * Capacity of solar panels
Capacity / total system size (number of panels * size of 1 panel)
Example:
16 panels * 265 watts = 4240 kilowatts (Capacity)
The total size of the system is 16×1.6=25.6
4240 / 25.6 = 165.62, around about 166 watts per meter square
5. Shade
Solar cells in the panel are connected and wired to form a series. Any part of the solar cell under shade will affect the overall power generation. It is because the current flows through the entire string of connected solar cells. Therefore, even if a part of the panel is under the shade it will influence the entire system and not just that one solar cell.
6. Time of the Day
During winter, daylight hours shift because every day the sun rises a little late and sets a little earlier than the previous day. This clearly affects the time period for which your solar panels receive sunlight and the average power it produces. There is uncertainty about the time when the solar panel system converts the power supply to the utility board.
7. Time of the Year
It relates to the season. Summer means abundant sunshine and power generation. Days are usually long during summer, which means there are more daylight hours, and your solar panels receive more power. This power is stored and used for days to come. However, this is not the case in winter.
8. Temperature
Solar panel output in winter vs summer is influenced by temperature. High temperature is not equivalent to high power generation. Ambient temperature is the key to maintaining the productivity and life of the solar power system. According to the source season, productivity and efficiency of solar panels decrease by about 0.25% for every degree increase in temperature above 77° Fahrenheit (25° Celsius). When your solar panels are exposed to excessively high temperatures, it causes a voltage drop between the solar cells, leading to a reduced optimum power generation capacity of the system. For example, solar panels of 100-Watt power exposed to 45° Celsius in summer will produce 75-Watt power.
9. Terrace (Rooftop) Orientation
The placement and angle of solar panels are two factors that ensure the panels receive maximum and direct sunlight during the day. Non-adjusted and wrong-angled solar panels will not produce a sufficient amount of power.
10. Type of Solar Panels
The material used in solar panels defines their efficiency. Modern solar panels are made from silicon, either monocrystalline or polycrystalline solar cells. Though both give similar energy output, monocrystalline solar panels use high-grade silicon, and this makes them more efficient than polycrystalline. Amorphous solar panels are also available, and they are more affordable than the rest, but their power production is also less. After this, let’s find out about solar panel output vs time of day and about what time of day do solar panels work best.
Also See: Superstorm Sandy – A Climate Change Reality Check
What is Solar Panel Output Vs Time of Day? What Time of Day Do Solar Panels Work Best?
The energy levels produced by solar panels differ with the time of the day. The efficiency of solar depends on the levels and amount of absorption they get. They work best during noon hours when the sun hits them directly and not from a particular angle. The max output must be calculated as per the range and not the time of the day.
Factors Influencing the Energy Output
- Type of illumination: Diffused or direct
- Weather
- Geographic Location
During the early morning hours, the output is considerably low due to the low intensity of sunlight. With an increase in intensity, solar panels tend to produce most energy between late morning hours to peak afternoon hours, that is 11:00 am to 04:00 pm. This decreases as evening approaches, and it falls to 0 at night. This should have helped you understand solar panel output vs time of day.
What is Solar Panel Output Winter Vs Summer?
After learning what time of day do solar panels work best, let’s find out in detail about solar panel output winter vs summer. No, this is not the case. Solar panels will produce electricity even in winter but there will be an average 50% reduction. According to the source solar panels tend to work more efficiently in cool months due to the even flow of electricity throughout the panels. Extremely high temperatures harm your solar panel whereas during cold weather solar panels cool down which increases their longevity and lifespan. And to prove this theory, you can see that nations like Germany, China, and Japan are leading solar power producers in the world.
- Average Solar Production on a Winter Day: It is unlike snow every day during winter except during the peak winter days. Therefore, the average daily solar production during winter could be half that in spring. This is better in comparison to snowy days when there is very little power generation. On some days it could be 120 kilowatt-hours whereas on other days it could be less or more.
- Average Solar Production on a Summer Day: Summer day means high temperature and lower efficiency of the solar power system. Average solar power generation on a summer day could be less than the power produced on a winter day. Yes, due to the reduced efficiency of the panels.
Also See: Does Ring Solar Panel Need Direct Sunlight?
What is Solar Panel Production by Month?
One thing that influences the solar output received from your solar panels is their temperature coefficient. It is always listed as a negative number on the datasheet of a solar panel. The closer that number is to 0 the better performance you can expect from your solar panel. Another factor to maintain efficiency during different months is the Pitch. Its optimum range is between 20 and 30 degrees for better power generation. A minimum of 10-degree pitch is recommended to allow leaves and rain to slip off the panel.
1. Measuring Solar Panel Output
To understand solar panel output in winter vs summer, you can calculate the output. Begin with calculating by taking out the output per day in Kilowatt-hour.
Size of 1 solar panel (square meters) * 1000 = X
X * Efficiency of 1 solar panel (percentage as a decimal) = Y
Y * Number of sun hours (area-wise each day) = Z
Z / 1000
For Example:
Size of panel = 1.6 square meters
Efficiency = 20%
Sun hours = 4.5
Therefore, 1.6 * 1000 = 1600
= 1600 * 20 /100 = 320
= 320 * 4.5 = 1440
= 1440 / 1000 = 1.44 kilowatt-hour per day
2. Output per Month
Daily output * 30 or 31
So, for the month of December
1.44 kilowatt-hour * 31 = 44.64 kilowatt-hours per month
What Time of Year Do Solar Panels Work Best?
Hotter does not mean more electricity generation. This is why the best time of the year for solar panels to work best is not summer but spring. This fact is known as the power temperature coefficient. It is listed on the solar panel datasheet as a percentage of power output loss per degree Celsius (%/°C).
For example, your solar panel has a power temperature coefficient of -0.30%. It means with every 1° Celsius increase in the temperature, your panel will produce 0.30% less power.
Here is the table based on the average estimated solar radiation and solar panel output per month in the United States. Energy conversation is assumed to be 15% efficient and on a standard solar panel of 1.6 meters squares.
| Month | Solar Radiation Per Month kWh/m2 (kilowatt-hour per meter square) | Solar Panel Output Per Month kWh (kilowatt-hour) | Solar Panel Output of 20 Panels Per Month kWh (kilowatt-hour) |
| January | 100.02 | 24.00 | 480.09 |
| February | 112.92 | 27.10 | 542.04 |
| March | 154.46 | 37.07 | 740.41 |
| April | 174.70 | 41.93 | 838.57 |
| May | 192.35 | 46.16 | 923.27 |
| June | 196.92 | 47.26 | 945.22 |
| July | 204.58 | 49.10 | 981.99 |
| August | 192.91 | 46.30 | 925.98 |
| September | 168.41 | 40.42 | 808.36 |
| October | 139.07 | 33.38 | 667.52 |
| November | 106.04 | 25.45 | 508.98 |
| December | 89.04 | 21.37 | 427.41 |
So today you got to know the difference between solar panel output in winter vs summer and the possible reasons behind it. Solar panel production by month also differs on the basis of the sun’s hours and other factors. How many sun hours do you receive in your region, and what is the average output of your solar power system?
Recommended: Can You Charge Solar Lights Inside?
