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How Efficient are Solar Panels?

By: Eric Huesca, SEO Content Writer

November 18, 2022

How well solar panels work is based on how much sunlight is reflected off their surfaces and turned into electrical or thermal energy.


Performance measures how much sunlight solar panel systems can turn into real power. The result shows how most efficient solar panels are.


How efficient solar panels are is based on how well their photovoltaic (PV) cells work and how well the panel as a whole works.

Customer happy with their solar panel installation

Customer happy with their solar panel installation

Because of all the changes in solar technology over the last few years, the average efficiency of solar panels has gone from 15% to well over 20%. Because of this significant boost in efficiency, the power rating of a typical-sized panel went from 250W to 400W.

The efficiency of a solar panel is equal to the sum of the efficiency of each cell that makes up the panel. Many things affect how well a cell works, such as how it is built and the materials used.


The National Renewable Energy Laboratory (NREL) says that most solar panels installed in homes and businesses today have efficiency ratings between 16% and 22%, with an average efficiency rating of 19.2%.


Solar panels with an efficiency rating of more than 20% are called “premium efficiency panels,” Because of this, they often cost more. Some well-known brands of high-efficiency solar panels are Sunpower, LG Solar, and REC Group.


Most solar panels today have an energy efficiency rating between 11 and 15%. This number shows how much solar energy is being turned into power that can be used.

It may seem like a small amount, but solar energy technology is always getting better, and the panels we have now are more than enough to meet the energy needs of most businesses and homes.


Scientists are always looking for ways to improve photovoltaic technology in the modern world. Researchers have reached a record efficiency of 40 percent by using multi-junction cells designed to collect different wavelengths of light on the electromagnetic spectrum. This is the new standard. But you can wait to buy them, even though they are the best solar cells ever made.


The most efficient solar panels may be the best choice for people with smaller roofs and less space to install them. Even though solar panels are a little more expensive because they are more efficient, you can be sure they will still meet your energy needs.


Photovoltaic, sometimes called “PV,” is the standard technology for solar electric systems. With this technology, energy from the sun can be made. Several solar cells are put together to do a module, which is what the panel is made of. It changes solar panel efficiency over time.

Panel Efficiency

Panel efficiency is one of the crucial factors that determine the performance of a solar energy system. It refers to the ability of a solar panel to convert sunlight into usable electricity. The higher the efficiency of a panel, the more electricity it can generate from a given amount of sunlight. This is especially important in areas with limited sunlight or space, where maximizing energy production is key.

The efficiency of a solar panel is influenced by various factors including the quality of photovoltaic (PV) cells used, the technology involved in panel construction, and the panel’s positioning relative to the sun. Recent advancements in solar technology have led to the development of highly efficient panels. Traditional monocrystalline and polycrystalline solar panels have efficiencies ranging from 15-20%, while newer technologies such as thin-film and bifacial panels offer varying degrees of efficiency. High-end PV cells can even reach efficiencies over 20%.

Efficiency is not the sole determinant of a good solar panel, but it certainly plays a significant role in the overall performance and size of the solar system. More efficient panels can generate the same amount of power in a smaller space, which can be a significant advantage for installations with limited available space.

However, it’s also important to balance the efficiency of a solar panel with other factors such as cost, durability, and warranty. Higher efficiency panels tend to cost more, but their increased electricity production could offset the extra expense over time.

Thin Film Panels

How do solar panels with PERC work? What do they mean? PERC panels are silicon cells that have been changed and have an extra layer on the back. They were first shown in 1989. This extra layer could make more energy by reflecting light and sending it back across the n-type and p-type junctions.


Solar panels made with PERC solar cells often work better than regular panels in places with low light and places with a lot of heat. By adding a layer to the back of a regular solar cell, PERC technology makes it the most efficient solar panel and benefits the manufacturing process.


Early commercial uses of PERC technology ran into problems, primarily because of the increasing damage caused by light. But thanks to constant improvements over the years, PERC modules now produce up to 12% more electricity from the sun than their traditional silicon counterparts.

By adding a dielectric passivation layer to the cell’s rear, an innovative method called PERC (which can also be written as Passivated Emitter and Back Cell or Passivated Emitter and Rear Contact) seeks to improve the efficiency of a solar panel. PERC stands for Passivated Emitter and Back Cell or Passivated Emitter and Rear Contact.


The increased solar energy collection that PERC panels provide makes them an excellent choice for sites constrained for space since they have a smaller overall footprint. They may still be manufactured with the same machinery.


They may have a lower average cost per watt because they are the highest-efficiency solar panels. Even though they require additional materials, their production costs are slightly higher than those of conventional solar panels.

What makes PERC panels different?

PERC, which stands for Passivated Emitter and Rear Cell, is a technology that significantly enhances the efficiency of a standard solar cell. The development of PERC technology has revolutionized the solar industry by allowing solar panels to capture more sunlight and convert it into electricity, making them an attractive option for homeowners and businesses aiming for maximum solar energy production.

The uniqueness of PERC panels lies in their additional layer on the rear side of the cells. In traditional solar panels, some of the light that reaches the solar cell passes through without being absorbed and is lost as wasted potential. However, in PERC panels, the added layer on the back surface of the cells acts as a mirror. This layer reflects unabsorbed light back into the cell, giving it a second chance to be absorbed and converted into electricity. This unique feature significantly enhances the panel’s energy production.

Another difference is that the added layer in PERC panels reduces the electron recombination process. Electron recombination hinders the free flow of electrons, which in turn reduces the electricity produced. The passivation layer in PERC cells helps to reduce this recombination, allowing more electrons to contribute to power generation.

Moreover, PERC panels perform better in low light conditions and higher temperatures compared to traditional panels. They also offer better bifacial performance, meaning if they are installed in a way that the backside is exposed to sunlight, they can generate electricity from both sides.

Despite these advantages, it’s important to note that PERC panels may come with a slightly higher price tag due to the advanced technology involved. However, this cost can be offset over time due to the higher efficiency and increased energy production, especially in areas with high electricity rates or abundant sunlight.

Passivated Emitter and Rear Cell Panels

In the 21st century, more and more solar panels are being made with PERC solar cells, which have a passivated emitter and a rear contact. PERC solar cells are just normal solar cells that have been changed in a way that lets them make between 6 and 12 percent more energy than regular solar panels.


The term “PERC cell technology” refers to a design for a solar cell that is different from the “standard cell architecture” used in the industry for the last 30 years and is often explained in photovoltaic instruction manuals.


Even though recombining the e-h pair under the above conditions is the usual way conventional solar cells make electricity, there is another type of recombination called surface recombination that causes losses for conventional crystalline silicon technology. It increases solar panel efficiency over time.


During surface recombination, a hole will interact with an excited electron that won’t pass through the contact. There will be a new electron made. During this phase, the e-h pair combines without making an electric current or solar electricity. Because of this, the solar cell could work better.

What makes PERC so unique?

The fact that PERC solar modules have the same structure as other silicon panels on the market is a big plus for the companies that make them.

Even though the cost of making passivation and rear contact capping layers is rising, panel makers can still use the equipment they already have to make panels with only a tiny amount of retooling.

Making PERC cells is about the exact cost of making regular silicon cells. Even though PERC panels are still a bit more expensive, these costs are more than made up for the highest efficiency solar panels, which saves the end user money on their electricity bills and reduces their carbon footprint.

As economies of scale and research and development continue to improve the technology, it is expected that PERC cells will continue to become more efficient and less expensive in the years to come.

Benefits of PERC cells

The PERC technology sends the photons back into the silicon layers, which gives the cell more power and stops electrons from recombining simultaneously. Because of these two benefits, solar modules can convert energy more efficiently, giving off less heat. Also, they promise that the cells will work better when there isn’t much light because they can make voltage with much less light than standard solar cells.

Poly PERC solar cells are made by mixing or melting several pieces of silicon to make the final product. In contrast, mono PERC solar cells are made from a single silicon crystal and do not have grain restrictions (2D defects). The higher purity of these mono PERC solar cells is one of the reasons these PV modules are more efficient, but it also makes them more expensive. It can affect the solar panel tilt efficiency.


Manufacturers may use almost all the same tools and materials to make PERC solar cells as they do for less efficient solar cells. Because of this, they are making PERC solar cells is a straightforward process. The PERC method works well in both mono-silicon and polysilicon solar cells. It also works well in bifacial configurations.

Monocrystalline Solar Panels

A solar panel with monocrystalline solar cells is called a monocrystalline solar panel. The panel’s name comes from a cylindrical piece of high-purity single-crystal silicon made in the same way as a semiconductor. Because the cell is made of a single crystal, the electrons can move around more freely, which makes the current flow better.

The wafers that will make up the cells from the cylindrical ingot are cut. The circular wafers are then cut with a wire to make an octagonal-shaped wafer that lets the cells work at their best. Because they are shaped like eight-sided boxes, these cells stand out. Also, they all have the same color.

They also have the significant benefit of being the type of solar cell technology expected to last the longest. At the moment, they are expected to last about half a century. Because of this, you will find that most

manufacturers will give you warranties on these solar panels that can last up to 25 years, which is about half of the time they are expected to last.

When light from the sun hits a monocrystalline silicon solar panel, the cells in the panel soak up the sun’s energy and create an electric field through a complicated series of steps. Based on the equation, this electric field is made up of voltage and current, and it is this field that makes power. Direct current devices can be powered directly from this source of electricity (DC). This electricity can also be turned into an alternating current with the help of an inverter (AC). This is why they are considered the highest-efficiency solar panels.

Monocrystalline PERC panels are made of cells, each made of a single crystal of silicon. Each crystal has the same shape and is pure black. They are in the shape of an octagon and have an extra layer of film on the back that can absorb sunlight that has been scattered or reflected. Polycrystalline perc solar panels for homes are 2 to 2.5 percent less efficient than monocrystalline perc panels.

Because of this, their performance is better than that of polycrystalline panels, especially when there needs to be more light or a high temperature. These panels give off 380 watts of power and don’t take up much room. This makes it much easier to put a monocrystalline PERC solar panel on a reasonably small roof than poly panels.


Even though this system is better than competing models in almost every way, it costs a lot more than other options. Compared to the other types of solar cells, monocrystalline solar cells are usually considered the most expensive option. This is mainly because each of the four sides has to be cut, which wastes a lot and tells you how efficient solar panels are. Because of this, polycrystalline is the more affordable choice.

Polycrystalline Solar Panels

Polycrystalline solar panels, also called multi-crystalline solar panels, are a type of solar panel that has many crystals of silicon inside a single PV cell. Many small pieces of silicon are melted and mixed when making wafers, the building blocks of polycrystalline solar panels. When polycrystalline solar cells are being made, the vat of molten silicon used to make the cells is left to cool on the panel on which it is being made.

These photovoltaic panels are made to look like a mosaic on the outside. Because they are made from many different polycrystalline silicon, they look like squares and are a bright blue color. Because there are many silicon crystals in each cell of a polycrystalline panel, electrons can only move through the cells very slowly. These solar panels can turn the energy that comes from the sun into power that can be used.


Polycrystalline solar panels are better for the environment than monocrystalline solar panels because each crystal doesn’t have to be a specific shape and position, and most of the silicon is used during manufacturing. So, there isn’t much waste. It makes them the highest efficiency solar panels.


These solar panels are made up of many different photovoltaic cells. Each cell can work as a semiconductor device because it has silicon crystals. When photons from the sun hit a PN junction, also called the junction of N-type and P-type materials, they give electrons energy, which lets them move as an electric current.

The surface of these polycrystalline solar panels looks like a mosaic, and they are made from several different types of polycrystalline silicon. Because of this, solar panels will last longer and work better in the long run. Each PV cell in these polycrystalline panels comprises an infinite number of silicon crystals arranged in a square mosaic. This allows electrons to move in more controlled ways, improving energy production.


In this case, P-type materials don’t have enough electrons, while N-type materials have more than they need. Two different electrodes are joined to the photovoltaic cells. The electrode on the bottom is more like foil than it is like wires. On the other hand, the electrode on the top is made up of tiny wires.

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