Dust and Pollution: How Your Solar Panels Lose Efficiency
Solar energy is one of the most promising sources of renewable energy. Its clean, abundant, and becoming more readily available. However, like any other tool we use to improve our lives, solar panels are not immune to the effects of environmental factors. Dust and pollution, can significantly impact solar panel efficiency.
In this article, we will explore the effects of dust and pollution on solar panel efficiency and how to mitigate their negative impacts.
How to clean dust from solar panels without voiding its warranty
Effects of Dust on Solar Panel Efficiency
Dust can have a significant impact on solar panel efficiency, particularly in regions with high levels of dust. Deserts and plains are regions that have the highest amounts of dust. Dust can accumulate on the surface of solar panels, reducing their ability to absorb sunlight. As the dust accumulates, it creates a layer that prevents sunlight from reaching the solar cells, resulting in a decrease in solar panel efficiency.
The effect of dust on solar panel efficiency depends on the type of dust, the amount of dust, and the duration of exposure. For instance, fine dust particles can penetrate the solar panel’s surface and cause internal damage to the solar cells, leading to a significant reduction in efficiency. In contrast, coarse dust particles can accumulate on the surface of the solar panel and block sunlight, resulting in a decrease in energy production. Either way, dust is destructive if left alone to its own devises.
According to studies, the amount of energy lost due to dust accumulation on solar panels can range from 5% to 20%, depending on the location and the level of dust. The impact of dust on solar panel efficiency is more pronounced in arid and semi-arid regions, where the dust levels are high. For instance, in the Middle East and North Africa, dust storms are a common occurrence, and they can significantly impact solar panel efficiency.
How to Mitigate the Effects of Dust
To mitigate the damage dust can cause to your solar panels, regular maintenance is essential. Regular cleaning of solar panels can help remove the accumulated dust and debris, improving energy production. Solar panel cleaning can be done manually, using water and a cleaning solution or by using automatic cleaning systems.
In arid and dusty regions, automatic cleaning systems are more effective in maintaining solar panel efficiency. These systems use brushes, sprayers, or air blowers to remove dust and debris from solar panels. Automatic cleaning systems can be powered by solar energy, making them an efficient and sustainable solution.
How often you clean your solar panels depends on where you live, how often you use your solar panels, and what kind of debris you are working with. Some experts recommend that you clean your solar panels once a year in the spring. Winter weather keeps dirt and debris lower to the ground, which means your solar panels get dirtier faster. In the summer, the warm air allows for dirt and debris to fly higher into the atmosphere, so your solar panels become less dirty. Other experts say to clean the panels every 6 months if you live in an arid region.
Thankfully, cleaning solar panels are quite easy to achieve. The best method to clean your panels is to use distilled water and a non-abrasive sponge or clothe to wipe down your panels. Distilled water is recommended over hose water because you won’t get mineral build up using distilled water.
Effects of Pollution on Solar Panel Efficiency
Pollution is another environmental factor that can negatively impact solar panel efficiency. Air pollution, in particular, can have a significant impact on solar panel efficiency. Air pollution can create a layer of particulate matter that blocks sunlight from reaching the solar cells, reducing energy production.
The impact of air pollution on solar panel efficiency depends on the type and concentration of pollutants in the air. For instance, studies have shown that the presence of nitrogen oxides and sulfur dioxide in the air can reduce solar panel efficiency by up to 20%. The presence of particulate matter in the air can also reduce solar panel efficiency by up to 10%.
Air pollution can also cause internal damage to solar cells, reducing their lifespan and efficiency. For instance, pollutants such nitrogen oxide can penetrate the solar panel’s surface and cause damage to the solar cells’ materials, resulting in a decrease in efficiency.
Researchers from the University of Jordan have proposed the use of electrostatic cleaning as an effective way to remove dust from solar panels.
Electrostatic cleaning involves the spraying of electrostatically charged mist with low-frequency high voltage onto surfaces and objects. It is commonly used for cleaning and disinfection purposes, and may involve the use of different electrically charging disinfectants, sanitizers, and cleaners.
The scientists said the glass in solar modules contains an equal number of positive and negative charges, which means it is electrically balanced. However, friction might disrupt this balance, causing the material to become electrically charged.
“The electrical charge will create an attraction force between the dust particles and the glass due to static charge causing dust accumulation over PV modules,” the researchers explained.
The academics proposed the use of an electrostatic ionizer, which uses ions to neutralize static electricity, in order to reduce the attraction between dust particles. They used an ionizer manufactured by UK specialist Exair, which could flood the PV module surface with uniform airflow across its length, loaded with static eliminator ions. The ionizer was placed on a shaft 0.2 m the shaft attached to a screw driven by an AC gear motor above the panel.
“The charged surface attracts the appropriate number of positive and negative ions to become neutral,” the researchers explained, noting that this process is able to charge the molecules of the gasses of the surrounding air, which in turn results in a shower of ions. “Stainless steel emitter points inside the Ion Bar receive 5 kVrms high voltage, via an armored and electromagnetic shielded high voltage cable. An integrated ground wire within the power cable creates a discharge path from the emitter to the bar channel.”
The Jordanian group tested the cleaning technique on a set of four 250 W polycrystalline solar modules mounted with a tilt angle of 25 degrees at the renewable energy center of Applied Science Private University in Amman. The performance was compared to that of natural cleaning and cleaning based on anti-reflective coating.
After two weeks of testing, the scientists found that the PV modules had an energy yield loss of around 5.93% with natural cleaning. They said that the coating was also about 3.8 times more economically feasible than electrostatic neutralization under the stated conditions in the study.
“However, the vanishing of the coating material after two weeks arising a recoating issue from an economic perspective compared with electrostatic neutralization where the running cost could be eliminated via developing a fixed mechanism with no moving parts,” the scientists said.
The group claims that the performance of the electrostatic cleaning technique could be further improved by enhancing its intrinsice mechanism.
“Even though nano-coating seems economic wiser than electrostatic cleaning, electrostatic cleaning has promising future for mega solar power plants in arid regions by advantage of less affecting by harsh outside conditions which require frequent coating, and the potential to develop a practical mechanism for electrostatic cleaning with less capital and running costs,” they said.
The scientists published their findings in “ Electrostatic cleaning effect on the performance of PV modules in Jordan,” which was recently published in Cleaner Engineering and Technology. In March, scientists from the Massachusetts Institute of Technology have developed a lab-scale solar module cleaning system prototype that uses electrostatic repulsion to cause dust particles to detach and virtually leap off the surface of panels.
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Emiliano joined pv magazine in March 2017. He has been reporting on solar and renewable energy since 2009.
Retiring the robotic arm
As a result of having less power, the mission team will soon retire the lander’s robotic arm from service. It will be used for the last time sometime later this month. Previously, the team was able to use the arm to remove some dust from the solar panels by “by trickling sand in the wind,” but that is no longer an option.
The arm was designed primarily to deploy InSight’s seismometer and “mole” heat probe. When the heat probe didn’t dig down deep enough into the ground as expected – after many attempts – the mission team used the arm to bury it in the soil, instead.
It’s a bad time of the year for dust in InSight’s landing location, Elysium Planitia. In fact, dust levels will now keep increasing over the next few months. At this point, a much more robust dust-cleaning event would be needed, such as a dust devil. Indeed, dust devils helped clean the solar panels of both the Spirit and Opportunity rovers. That could happen with InSight as well, but mission scientists seem to think it is unlikely.
As Bruce Banerdt, InSight’s principal investigator at NASA’s Jet Propulsion Laboratory (JPL), stated:
We’ve been hoping for a dust cleaning like we saw happen several times to the Spirit and Opportunity rovers. That’s still possible, but energy is low enough that our FOCUS is making the most of the science we can still collect.
Prioritizing energy on InSight
As of now, the seismometer is being given the priority in terms of science instruments. It still operates at various times of day and night. It does so when winds are at their weakest, allowing it to detect the faint marsquakes more easily.
During its mission, InSight has recorded over 1,300 marsquakes. This is evidence that the planet is still geologically active beneath the surface. The biggest marsquake detected so far is magnitude 5.0. That’s a medium quake on Earth, but it’s impressive for Mars. After all, Mars lacks plate tectonics, the process that, on Earth, shifts land plates around, building mountains and creating most earthly volcanoes and earthquakes.
The previous largest marsquake recorded by InSight had measured 4.2, which is very mild by earthly standards.
InSight’s mission has two main goals: to understand the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars, and determine the present level of tectonic activity and meteorite impact rates on Mars.
The mission has transformed our understanding of Mars’ interior geology as never before. According to Lori Glaze, director of NASA’s Planetary Science Division:
InSight has transformed our understanding of the interiors of rocky planets and set the stage for future missions. We can apply what we’ve learned about Mars’ inner structure to Earth, the Moon, Venus, and even rocky planets in other solar systems.
Bottom line: NASA announced on Tuesday that it is winding down the InSight lander mission on Mars, due to increasing dust on its solar panels. Science operations will end this summer, with full mission shutdown by this winter.
How Often Should I Clean My Solar Panels?
In most cases, you only need to clean your solar panels once or twice per year. We recommend scheduling your annual cleaning routine during the spring. That avoids the heat of summer and harsh elements of winter.
Should You Clean Your Solar Panels? Before/After Testing!
However, your solar panels might need extra attention in some locations. For example, the Southwest US experiences more significant dirt accumulation because of limited rainfall. Also, panels in homes near airports, factories, freeways, and other sources of pollution will need more frequent cleaning.
Winter and autumn are other special cases. Removing heavier-than-average snowfall and leaves can boost your solar performance significantly.
Do I Clean Off Snow?
We get it. heavy snowfall days can make anyone nervous about their system not generating enough energy. However, snow on your solar power panels usually melts away quickly, thanks to the heat created by the solar panels, and their slick surface. Snow on a panel melts faster than on an empty roof due to the high difference in heat between the two surfaces.
But if the snow is taking longer to melt and your battery storage is running low, you don’t have to wait. You can brush the snow off your panels to get them back to producing power right away.
Make sure you use the right equipment to avoid damaging your investment and compromising its warranty. Thus, shovels, standard brooms, and other non-specialized tools should not come anywhere near your panels. A suitable snow roof rake created for the task will come in handy here. They typically cost around 30 to 150.
Can I Use a Pressure Washer When Cleaning My Solar Panels?
No. Not at all. High-pressure water is among the biggest enemies of your solar equipment.
First, high-speed moisture can quickly force its way through the seals around the frames and get into vulnerable technology. These water leakages can promote corrosion of the fine wires, which leads to the failure of the solar panel and its photovoltaic cells.
Also, the glass surface can break under high water pressure. We hear you asking, Why then don’t we see damage resulting from continuous rainfall pounding on the glass? That’s because panels are designed to resist hours of heavy rain falling across a wide surface area. But washing the panels with high pressure directs a focused beam of water in a highly concentrated spot, which creates an increased chance of stressed areas that can crack.
What is Localized Soiling?
Localized soiling of solar panels is when material like bird poop, leaves, and any other heavy blockages get stuck on your panels, but only cover part of the panel. Compare that to general soiling, where material like dirt and dust covers the entire panel surface.
When rain and wind fail to remove localized soiling, this sort of debris may block some parts of the equipment, leading to hot spots.
Your panel is made of several individual cells (60 in most cases). When localized soiling blocks sunlight from reaching one of the cells, its energy production drops. However, full current flowing from the adjacent cells may pass through the affected one. The result is overheating at that cell, a phenomenon that can cause damage to the panel.
Yes, modern solar panels come with multiple built-in bypass diodes to keep hot spots at bay. But those extra-dirty areas can still lead to damage over time that can increase your solar panel maintenance cost.