Are you looking for how to increase the efficiency of your solar panels? If so, you’re in luck! This blog post will discuss tips that will help you get the most out of your solar panels. By following these simple tips, you can maximize your energy output and reduce your carbon footprint. Let’s get started!
Even as we promote solar power as the main arsenal in our fight against climate change, do you know that the solar panel efficiency level is abysmally low?
Yes, it’s true. The conversion rate of solar panels is at best 22% and sometimes even as low as 11%.
And, when you compare this with the 35-40% average efficiency level of a wind turbine, you will be appalled at how bad it really is.
However, the story doesn’t end there. There are ways to increase efficiency of solar panels to as high as 50%. Read on to learn about the efficiency levels of various types of solar panels and how to improve solar panel efficiency.
To understand the efficiency levels of solar panels, we first need to learn more about how solar panels are made and how they work.
How are solar panels made?
A solar panel is an arrangement of solar cells interconnected electrically and sealed with tempered glass on top and a back cover for protection. The color and appearance of the solar panel depend on the type of solar cells used in it.
There are three types of solar cells used in the manufacture of solar panels today.
A monocrystalline solar panel is made from a single silicon crystal.
A polycrystalline solar cell is made from fragments of silicon crystals melted together.
A thin-film solar cell can be made from a variety of materials – amorphous silicon (a-Si), cadmium telluride (CdTe), and Copper Indium Gallium Selenide (CIGS).
Here is a quick comparison of the 3 solar cells.
|Made from a single crystal of pure silicon||Made from fragments of silicon crystals melted together||Made from a variety of materials|
|Black in color||Blue in color||Can be black or blue|
|Square with cut corners||Square with no gaps||350 times thinner|
|Max efficiency 22%||Max efficiency 15-17%||Max efficiency 11%|
|Most expensive||Moderately expensive||Cheapest|
|Lifespan 25-30 years||20-25 years||15-20 years|
How do solar cells produce electricity?
The solar cells use the photovoltaic effect to convert solar energy into electric energy.
When sunlight falls on a semiconductor surface, the energy from photons in the sunlight is transferred to the electrons of the material. This makes the electrons more active and they escape the bond binding them with the atom. The flow of electrons results in an electric current.
A solar cell consists of two types of semiconductors – p-type and n-type – placed closely together to form a p-n junction. A p-type is positively charged and has holes, while the n-type is negatively charged and has an extra electron.
When sunlight falls on the n-type semiconductor, the extra electron gains energy and jumps across the p-n junction to fill up the holes on the p-type semiconductor. When the escaping electrons are brought back to the n-type layer with external wiring, the electron flow can be maintained consistently. This constitutes electricity.
Why are solar panels so low in efficiency?
The ability of solar cells to generate electricity depends on the ability of the photons to impart enough energy to the electrons so that they jump across the p-n junction.
Almost 23% of the photons are not energetic enough to trigger the flow of electrons in the semiconductor. Another 33% of photons are so energetic that most of the energy is lost as heat energy. About 16% of the energy is lost by the electrons during the process.
In theory or laboratory conditions, monocrystalline cells can reach maximum efficiency of 33%. But in real-world conditions, this is around 22%.
In polycrystalline and thin-film cells, the energy lost is higher and hence the efficiency is lower.
What are the other factors affecting solar cell efficiency?
Irradiance and insolation are two main factors affecting the efficiency of a solar installation.
Irradiation is the measure of the energy density of sunlight, while insolation is the amount of solar radiation received. When the irradiation and insolation are high, the solar cells manage to convert more solar energy into electrical energy, resulting in higher efficiency levels.
The amount of sunlight received by the solar cell depends on its positioning, orientation, and tilt. For a fixed solar panel, exposure to sunlight will be lower as the sun changes its position during the day and across the seasons.
In the northern hemisphere, solar panels are recommended to be positioned facing south to maximize exposure. If fixed mounts are used, the tilt is adjusted in such a way that the cell receives maximum sunlight at noon. This means before and after the noon hour, the conversion efficiency of the solar panel will be lower.
What can be done to improve solar panel efficiency?
Besides using high-efficiency solar panels with monocrystalline cells, the most common methods used to raise the efficiency of solar panels are
- Solar concentrators
- Solar reflectors
- Solar trackers
1. Solar concentrators
Ever tried using a lens to focus the sun’s rays onto paper to start a fire? Solar concentrators use the same principle.
The solar concentrators use lenses, called Fresnel lenses, to trap the sunlight from a large area and direct it onto the solar panel. Lenses of different concentration levels are used based on the material used in the manufacture of solar cells.
For monocrystalline and polycrystalline solar cells, a low concentration lens is sufficient. Moreover, this doesn’t require tracking or cooling.
Thin-film solar cells made using cadmium, telluride, or silicon require concentration lenses of medium strength. This often demands some levels of tracking and cooling.
The newer generation of solar cells like multi-junction or multi-material cells can work more efficiently when paired with high concentration lenses. This necessitates extensive cooling and good tracking.
Though the materials used in making the solar cells remain the same, the structure of the cells is different when they are to be paired with Fresnel lenses. The surface area of the solar cell is much smaller when compared to traditional solar cells. This can bring the price of quality solar panels down as less semiconductor material needs to be used in their manufacture.
When a concentration lens is used with a traditional solar panel, it can cause more damage than good with excessive irradiance. This leads to wastage of energy as heat and overheating of the solar panels, resulting in further reduction of efficiency.
2. Solar reflectors
Even as the lens refracts or bends the sunlight to direct it in a specific direction, mirrors reflect sunlight to achieve the same result. Though not used extensively at present, solar reflectors use mirrors to converge sunlight onto the solar cells.
Diverse types of solar reflectors are being developed and the research is showing very promising results in improving the efficiency of solar panels. The simplest form of solar reflectors uses flat mirrors kept at required angles close to the solar panel so that the incident sunlight is reflected to fall on the panel surface.
More advanced versions of solar reflectors include parabolic mirrors. Overheating is an issue that needs to be tackled when using solar reflectors. However, this has much potential in colder regions with already high insolation levels. When cooling technology is employed simultaneously, solar reflectors can increase efficiency of solar panels up to 30%.
3. Solar trackers
To get the best energy output from a solar panel, it has to be perpendicular to the sun’s rays. This is not practically possible when using a fixed mount as the sun changes its position during the day and as the seasons change.
So, when using a fixed mount, the median orientation and tilt are used. This means only for a short interval, the solar panel will be facing the sun at right angles. On all the other occasions, it will be at a disadvantageous position, wasting some or most of the incident sunlight. This leads to low conversion efficiency.
While seasonal differences can be manually adjusted, daily change in the position of the sun is hard to account for. This is where solar trackers can be immensely useful.
Though more complicated and expensive to install, solar trackers can ensure that the solar panels receive the maximum sunlight available in your location. This means more energy generation and higher returns on investment.
Solar trackers are of two types – single-axis and dual-axis. While single-axis trackers can raise efficiency by almost 20%, dual-axis trackers can do a much better job by increasing it by 30%.
Constant monitoring of solar panel output can alert you of any drop in its efficiency levels. Over time, solar panels tend to become less efficient due to degradation or damage. Overhanging trees or high-rise buildings nearby can cast shadows, thus bringing down the efficiency.
Accumulation of dust, dirt, debris and bird droppings can also result in reduced efficiency. Periodical cleaning of the panel surface with water can solve this. If using a fixed mount, getting a professional to install solar panels can make a huge difference. Those familiar in the field know how to calculate the exact orientation and tilt angle to get the best out of the installation.
Another choice available to you is high concentrated photovoltaic (CPV) cells. Though highly expensive, these high-output solar panels come with an impressive efficiency of 46%.
The decision to go solar is both a lucrative and noble act. It is also important that you get the best out of the solar panels. These suggestions should help you find the most efficient solar panels and get optimal performance from your solar power installation.