So you’re thinking of installing a solar system. The investment is worth it, considering its environmental and cost benefits. However, many solar companies claim that homeowners can enjoy a 50-60% reduction in energy costs after installing the system. But the truth is that the benefits solar panels can give you depend on their efficiency. The first primary factor that affects the efficiency is the type of solar panels followed by the weather conditions and the upkeep.
Learning about the efficiency factors is important because it lets you choose the best type of panels, pick the right solar company for installation, and know what upkeep it requires to keep working efficiently.
In this article, we discuss the factors that affect solar panel efficiency so you can make a wise investment decision.
Factors Affecting Solar Panel Efficiency
Solar Panel Type
The type of panels you pick plays a huge role in solar panel efficiency. There are mainly two types of panels: monocrystalline panels and polycrystalline solar panels. The visible difference between the two is the hue. While polycrystalline material gives a bluish, grainy hue, monocrystalline panels are sleek black.
But that’s just the visible difference. The use of multiple silicon crystals in the solar cells makes polycrystalline panels less expensive, but less efficient too. The efficiency of these panels lies between 13-16%.
Monocrystalline solar panels, as the name suggests are made from a single crystal structure. These high-quality solar panels boast a 15-24% efficiency. However, because these panels are expensive to produce, they are sold at a higher price than polycrystalline.
Thin-film Solar Panels
Thin-film panels have recently made a debut in the world of solar technology so they have a long way to go. However, right now, thin films have an efficiency between 7–12%. The efficiency bracket is so huge because the efficiency of thin films depends on the material. Thin film panels made of amorphous silicon (a-Si) have a 6-8% efficiency while those made of copper indium gallium selenide (CIGS) have a 10-12% efficiency rate.
Amount of Sunlight
The amount of direct sunlight that an area receives also impacts how efficient solar is. Those areas that have a lot of sunny days get a lot of solar power. On the flip side, the areas that have cloud cover and get a lot of rain get lesser renewable energy from the solar panels. This amount of sunlight can vary based on the time of the year as well. Some areas that experience a lot of sunny days during the summers could have cold winters with cloud covers that impact the efficiency.
But the good news is that the latest technology in solar PV panels has enabled it to produce electricity even during cloudy weather conditions. So, the sunlight that is dispersed by the clouds can also be used by solar cells to generate energy.
Panel Orientation and Tilt
The angle of incidence also impacts panel performance. This is the reason why flat rooftops have to get a mounting system created to keep the panels at a tilted angle.
Ideally, solar panels should be installed at a 15-20 degree tilt. To maximise year-round production, Samso Solar’s experts recommend figuring out your angle of latitude. This angle will be the minimum angle for panel tilt and latitude plus 15 degrees is your maximum angle for panel tilt.
The tilt makes sure that the panels receive adequate sunlight throughout the day. Solar panels should point directly at the sun in the middle of the day. But figuring that out is up to the experts.
Another thing to note is the panel’s orientation. Solar panels in the northern hemisphere should face south while those in the southern hemisphere should face north. However, some pitched roofs have an odd orientation. Professional solar installers make sure that they achieve the best possible orientation with any roof type.
Temperature
Contrary to popular belief, heat actually reduces panel efficiency. So, direct heat on the hottest days of the year will not yield more energy because as the temperature increases, the solar panel resistance also increases. When the resistance increases, it slows down electric current and therefore, lowers energy production.
Solar panels are most efficient between 15°C and 35°C (59°F and 95°F). Any higher or lower than this temperature means that the efficiency is being impacted because of the temperature.
Shading and Obstructions
Shading and obstructions like tree trunks or shade from nearby buildings could obstruct the direct sunlight. Since panels perform most efficiently when they receive direct sunlight between a certain temperature, any obstructions or shades will reduce the efficiency.
So, while installing the panels, it is important to be mindful of any objects that may obstruct the panels. If there are trees, it is best to trim them regularly so the panels receive ample direct sunlight to produce energy. If there are buildings nearby, panels should be placed at an angle that is free from the shade at the prime time of the day.
Common causes of shading (trees, buildings, etc.)
Dust and Dirt
Dust, dirt, and bird droppings can form a barrier between the panels and the sunlight, thereby reducing their efficiency. So, cleaning the panels is a part of the maintenance that keeps cell efficiency high.
Here are some cleaning and maintenance tips for you to follow:
- Timing: Clean your panels during the cooler parts of the day, such as before sunrise or after sunset, to avoid thermal shock.
- Water: Use lukewarm and clean water to rinse the panels. Avoid using high-pressure water as it can damage the cells.
- Cleaning Solution: A mild detergent solution is sufficient for most cleaning. Avoid harsh chemicals, abrasives, or solvents that can damage the panel surface.
- Cleaning Tools: Use a soft cloth or sponge to gently wipe the panels. Avoid using hard brushes, wipers, or abrasive materials.
- Frequency: In some parts where there is a lot of dust and pollution, installers recommend the property owners wash the panels on a weekly or bi-monthly basis. However, if the area receives adequate rainfall, panels won’t need cleaning very frequently.
Age of the Solar Panels
Solar cells gradually lose the ability to produce solar energy over time just like all technological devices. The rate at which solar cells degrade is typically around 0.5–0.8% per year.
While this may seem insignificant, it can accumulate over time, reducing the overall solar energy output of the system.
The solar panel degradation curve is 2-3% in the first year because of light-induced degradation. The decline rate is steady and under 1% in the next decade or more. Typically, solar panels last around 25-30 years. Because the rate of performance decline is so low, you might start noticing the decline around the 20-year mark, you will see that the panels are not as efficient as they were before.
Inverter Efficiency
The inverter is what converts the direct current produced by the panels into alternate current, ready to be used by machines in a commercial setting and household appliances in a residential setting. During the conversion process, some of the electricity is lost as heat. This is called energy conversion loss and can be seen in other energy conversion processes, such as converting electrical energy into mechanical energy in electric motors or converting chemical energy into electrical energy in batteries.
Different inverter technologies, such as string inverters and microinverters can also impact efficiency. For instance, string inverters offer 99% efficiency while microinverters have a 97% conversion efficiency. The quality of the inverters has a lot to do with the efficiency as well.
The size of the inverter also has a lot to do with the efficiency of the overall system. Inverter sizes should match the output demand and the panel array. If it is oversized or undersized, that too can impact the panel’s efficiency.
Conclusion
A number of factors impact the efficiency of solar panels. These factors include the type of panels, amount of sunlight, temperature, panel orientation, dust and debris, age of the panels, and inverter efficiency.
While few of these factors depend on the natural environment like dust, temperature, and the amount of sunlight, a number of these factors are controllable. For instance, the panel’s orientation, the type of inverter, and the obstruction are some factors that can be changed to maximise production. In addition to this, a regular cleaning and maintenance schedule is also a factor at play in keeping the panel performing efficiently over its life.
To get these controllable factors on point, hiring a professional installer is recommended. Samso Solar has highly experienced, vetted professional installers on board. These experts have local knowledge and technical knowledge regarding solar panels to give their clients the maximum possible efficiency.
