What Are the Most Efficient Solar Panels in 2024?

Solar panel efficiency (conversion rate) is the ability of a solar panel to convert sunlight into electrical energy. Solar panel efficiency describes the ratio of electrical output (in watts) to the amount of sunlight that strikes the surface of the panel ( in watts per square meter). 

Solar panel efficiency is expressed as a percentage. For example, if a solar panel has a conversion rate of 20%, this means that it can convert 20% of the incoming sunlight into usable electrical power. The most efficient solar panels (photovoltaic technology) produce the most power output.

Recent advances in photovoltaic technology (N-type HJT, TOPcon, and IBC) have led to a increase in solar panel initial efficiency and wattage, from an average of 15% to more than 23%. Recent advances in photovoltaic technology has resulted in a corresponding increase in the power output of standard-size solar panels, from 250 Watt to 460 Watt. 

When choosing solar panels, it’s both the wattage and efficiency are important. high wattage solar panels generate more electricity, but higher efficiency ensures that a greater percentage of sunlight is effectively converted into usable power, making the system more space-efficient or cost-effective.

But, how efficient are solar panels? the maximum solar panels’ theoretical efficiency is 86.8%. However, the actual solar panels’ efficiency is much lower than theoretical efficiency. Even though we still can maximize the efficiency. The future of solar panels’ efficiency is with some cell types like Perovskite solar which is expected to reach an initial efficiency of 29% by 2030.

Even with the best types of solar cells (Perovskite solar), there still be external factors that affect the efficiency of solar panels (temperature, sunlight, shading, solar systems’ quality, dirt and dust which require solar panel cleaning).

The article answers the following questions: What Are The Highest Efficiency Solar Panels? How Efficient Are Solar Panels? What Happens to The Solar Panels’ Efficiency Over Time? What is Solar Panels’ Initial Efficiency? What is a Solar Panel’ Degradation? How to Increase (Maximise) Solar Panels’ Efficiency? What is Solar Panels’ Efficiency Future? What is the Highest Watt Solar Panel? Why Choose the highest Watt Solar Panel? What are The Factors That Affect Solar Panels’ Efficiency?How Does Shading Affect the Efficiency of Solar Panels? How Does Temperature Affect the Efficiency of Solar panels? How Does Sunlight Angle Affect the Efficiency of Solar Panels? How Do Dirt and Dust Affect the Efficiency of Solar Panels? How Does Solar System’s Quality Affect the Efficiency of Solar Panels?

What Are The Highest Efficiency Solar Panels?

The highest efficiency solar panels are built based on high-performance “N-type HJT, TOPcon” and “Back-contact” (IBC) cells. Recently, Aiko Solar released the Black Hole series panels module with an efficiency of 23.6%, using a unique new ABC (All Back Contact) cell technology. A next-generation “Black Tiger series” achieves 23.6% efficiency using a new “TOPcon Back-contact” cell design, by Recom Tech company. There is also a module efficiency level of 22.8% using the “Hi-Mo 6 Scientists series” by LONGi Solar Company.

The following picture shows the top 10 most efficient solar panels from different manufactures.

Solar cells’ efficiency is determined by its structure and the type of silicon substrate used, which can be either P-type or N-type. A Cell’s conversion rate is calculated using the fill factor (FF), which is the maximum conversion efficiency of a solar cell at its optimal voltage and current. It is important to note that cells’ efficiency is not the same as panel efficiency, which is always lower due to the internal cell gaps and frame structure.

The cell’s design and material are very important for efficiency. the 4 key factors influence the cells efficiency are in the following list. 

• The silicone type
• Busbar configuration
•  Junction type
•  Passivation type (PERC).

N-type Back-contact (IBC) cells are currently the most efficient (up to 23.8%), N-type is a high-pure silicon substrate that prevents shading losses. Solar panels that use the latest N-type TOPcon and advanced heterojunction (HJT) cells have achieved efficiency levels above 22%. Ultra-high-efficiency tandem perovskite cells are still in development, but we expect that they will be commercially viable within the next two years.

Different solar cells’ efficiency according to types, designs, configurations are shown in the following figure.

The highest efficiency solar panels built by N-Type Interdigitated back contact (IBC). The lowest-efficiency solar panels are 60-cell poly PERC (multi-crystalline panels). 

To know how efficient are solar panels, we look at the Monocrystalline, Polycrystalline, and Thin-Film Panels ‘efficiency. 

How Efficient Are Solar Panels?

The most efficient solar panels available today are about 23.8% efficient, even though the maximum solar panels’ theoretical conversion rate is 86.8%, according to laws of physics. However, the actual efficiency of solar panels is much lower than this. 

Solar panels’s efficiency varies widely depending on the type of panel, its construction, and the conditions under which it operates. The following list shows the efficiency of the top 3 common types of solar panels

• Monocrystalline Panels. These are the most efficient panels, with efficiencies ranging from about 17% to 22.8%.
• Polycrystalline Panels. These panels are generally less efficient than monocrystalline panels, with efficiencies ranging from 13% to 16.9%.
• Thin-Film Panels.These are the least efficient solar panel technologies, with efficiencies usually ranging from 10% to 12%. However, they are often cheaper and more flexible.

How efficient are solar panels can be calculated by dividing the amount of electricity they produce by the amount of sunlight received. 

The formula of calculating a solar panel’s efficiency is in the next picture.

Efficiency = (power output/incident radiation) * 100%

• Power output. it is the amount of electricity produced that a solar panel can produce in watts.
• Incident radiation. It is the amount of sunlight that hits the solar panel in watts per square meter.

For example, if a solar panel has a power output of 100 watts and receives incident radiation of 1000 watts per square meter, then the panel’s efficiency is 10%.

The result of this equation (Solar panels’ initial efficiency) changes by degrading over time. To save initial efficiency, there are 3 useful practices to do (using a tracking system, cleaning solar panels, choosing high-efficiency solar panels).

What Happens to The Solar Panels’ Efficiency Over Time?

Solar panels’ efficiency decrease over time. Solar panels’ efficiency does not remain constant throughout the lifespan of solar panels. Solar panels’ efficiency degrade over time because of 4 reasons are exposure to Sunlight, weather conditions, micro cracks and soiling, bad manufacturing quality.

The breakdown of solar panels’ efficiency ages is initial efficiency and degradation. Between the initial efficiency and the percentage of decline in efficiency, you can increase (maximize) solar panel efficiency through some procedures.

What is Solar Panels’ Initial Efficiency?

The initial efficiency is when a solar panel is brand new and installed, it typically operates at or near its rated efficiency. With the initial efficiency, a solar panel can convert a high percentage of the sunlight it receives into electricity. The initial efficiency depends on the type of solar panel. Monocrystalline panels generally start at a higher efficiency level than polycrystalline or thin-film panels.

The following list shows the initial efficiency of the most 3 common types of solar panels.

• Monocrystalline panels have the most initial efficiency, with efficiencies ranging from about 17% to 22.8%.
• Polycrystalline panels have less initial efficiency than monocrystalline panels, with efficiencies ranging from 13% to 16.9%.
• Thin-Film panels have the least initial efficiency solar panel technologies, with efficiencies usually ranging from 10% to 12%. However, they are often cheaper and more flexible.

What is a Solar Panel‘ Degradation?

Solar panels’ efficiency degradation (aging) is a natural process that happens through time. The gradual reduction in efficiency is caused by 4 main factors are in the following list.

• Exposure to Sunlight. Over time, exposure to sunlight, UV radiation, and temperature fluctuations can cause materials in the solar panel to degrade slightly. This can result in a gradual reduction in efficiency.
• Environmental Factors. Weather conditions, such as extreme heat, cold, or humidity, can affect the efficiency and performance of solar panels and contribute to degradation.
• Micro cracks and Soiling. Micro cracks or accumulation of dirt and dust on the panel’s surface can increase the degradation, and reduce its ability to capture sunlight effectively.
• Manufacturing Quality.The quality of manufacturing and the materials used can also influence the degradation rate over time.

The degradation rate varies depending on the quality of the panel and its manufacturer. On average, high-quality solar panels tend to degrade at a rate of about 0.5% to 1% per year, according to the Solar Energy Industries Association (SEIA). This means that after 25 years (the typical warranty period for most solar panels), a panel can still operate at 75% to 87.5% of its initial efficiency.

How to Increase (Maximise) Solar Panels’ Efficiency?

To increase (maximize) solar panel efficiency you should follow the 7 steps in the next list.

• Choose high-efficiency solar panels. Panels with higher conversion rates produce more electricity from the same amount of sunlight.
• Install the panels in a sunny location. Solar panels work more efficiently in direct sunlight. 
• Clean solar panels regularly. Dust, dirt, and bird droppings can reduce the efficiency of solar panels.
• Use a tracking system. A tracking system automatically orients the panels towards the sun throughout the day, which can increase their efficiency by up to 30% or more.
• Use microinverters. Microinverters convert the electricity from each solar panel individually, which can help to improve efficiency in shaded areas.
• Oversize the system. Oversizing the solar system means installing more panels than you strictly need. This can help to compensate for losses due to shading and other factors.
• Use a solar monitoring system. A solar monitoring system can help you track the performance of your solar panels and identify any potential problems.

What is Solar Panels’ Efficiency Future?

The future of solar panel efficiency is bright. There are many ongoing research and development efforts aimed at improving the conversion rate of solar panels. 3 main promising technologies are in the following list.

• Perovskite solar cells. They are made from a material called perovskite, which is a cheap and abundant material. Perovskite solar cells have the potential to reach an efficiency of 29% by 2030.
• Multi-junction solar cells. They are made from multiple layers of different semiconductor materials. Each layer absorbs a different wavelength of sunlight, which allows the solar cell to absorb more of the sun’s energy. Multi-junction solar cells are already very efficient, and they are expected to become even more efficient in the future.
• Concentrating solar power (CSP). CSP systems use mirrors or lenses to concentrate sunlight onto a small area. Then, CSP systems convert sunlight into heat and then into electricity. CSP systems can be very efficient, and they are a good option for areas with high levels of sunlight.

The future of solar panels’ efficiency is visualised in the following chart.

What is the Highest Watt Solar Panel?

The highest watt solar panel is a panel that can generate the highest power under standard test conditions. Standard test conditions (STC) are a set of standardized conditions under which the performance of solar panels is measured and rated for consistency. These conditions include a specific level of sunlight intensity and a temperature of 25 degrees Celsius (77° Fahrenheit).
Trina Solar, Jinko Solar, Canadian Solar, Risen Energy, and JA Solar are the first who introduced high wattage solar panels that exceed 600W in the last two years. Then Huasun, TW Solar, Jolywood, and the relatively less known Akcome introduced high wattage solar panels that exceed 700W. These breakthroughs are attributed to the adoption of cutting-edge technologies such as N-type TOPCon or heterojunction (HJT) cell technology.
Interestingly, SunPower (now Maxeon) and REC, recognized premium module manufacturers, have opted not to participate in the race for larger format high-power panels. Instead, they have chosen to concentrate on meeting the needs of their traditional residential and commercial customer base by supplying compact-sized, high-efficiency panels.
The Wattage (W) is a unit of power that measures the rate at which electrical energy is produced or consumed. In the context of solar panels, the wattage is the amount of power a solar panel can generate under standard test conditions (STC). Standard conditions involve a specific sunlight intensity, temperature, and other factors for consistent measurements. The term “watt-peak” (Wp) indicates the maximum power output of a solar panel under STC. For instance, if a solar panel is rated at 300 watts (300Wp), it means it can produce 300 watts of electrical power under those standardized conditions.

The solar panel’s wattage is a crucial factor in designing solar power systems to meet the energy needs of a given application. Advancements in technology lead to higher-wattage solar panels, enhancing the efficiency and compactness of solar installations.

The high watt solar panels in the market are in the following picture

Choosing the highest Watt Solar Panel has 5 advantages including (Space Efficiency, Future-Proofing, and Technology Advancements).

Why Choose the highest Watt Solar Panel?

A highest wattage solar panel is better because it signifies a higher power output capability for a single solar panel. The highest watt solar panel is the solar panel that can generate more electricity under standard test conditions (STC), making it more efficient in converting sunlight into electrical power.

The following figure shows highest watt solar panels 5 advantages.

The 5 main advantages of high watt solar panel are in the following list.

• Save Space. A solar panel has a high watt allows for more power to be generated in a given amount of space.
• Help to Reduced Installation Costs.Few number of high watt solar panel are be needed to achieve a specific power output, which can result in lower installation costs, as it requires fewer mounting structures, wiring, and labor.
• Increase Energy Production. Systems using the highest watt solar panel can produce more energy, making them suitable for meeting higher electricity demands or offsetting a larger portion of a household or business’s energy consumption.
• Ensure Technology Advancements. High wattage solar panels incorporate technological advancements that improve overall efficiency, durability, and performance.
• Meet Increased Demands. Investing in a highest wattage solar panel ensures that the solar power system is equipped to meet increasing energy needs or potential expansions in the future.

What are The Factors That Affect Solar Panels’ Efficiency?

Solar panels’ efficiency in producing electricity is not constant at all times, conditions, and places. The 4 main factors that affect the efficiency and the conversion rate are in the next list.

• Shading
• Temperature
• Cleaning
• Quality of the components

The 4 main factors that affect the efficiency and the conversion rate are in the next picture.

How Does Shading Affect the Efficiency of Solar Panels?

Shade reduces a solar system’s efficiency. Shade makes householders lose about 40% of the potential for solar generation according to a study by the National Renewable Energy Laboratory (NREL) found that . Shading, in the context of solar panels, is any obstruction or blockage that prevents sunlight from reaching a portion of the solar panel surface.

In the next list, there are 5 ways that shade effects solar panel conversion rate (efficiency).

• Reduce Overall Power. When a solar panel or a portion of it is shaded, it reduces the amount of sunlight that can be converted into electricity. 
• Bypass Diodes. Most solar panels are equipped with bypass diodes. These diodes allow the current to bypass a shaded or low-performing cell within the panel. This prevents a shaded cell from dragging down an entire panel’ efficiency. However, even with bypass diodes, shading still reduces the panel’s overall efficiency.
• Partial Shading. where only some of the cells on a panel are shaded, can have a more significant impact on efficiency than complete shading. This is because the bypass diodes are more effective in mitigating the effects of full shading.
• Mismatch Losses. Power losses that occur due to slight differences in the electrical characteristics of different solar modules in a solar panel array.  When cells on the same panel are subjected to different levels of sunlight due to shading, mismatch losses occur. Mismatch losses can significantly reduce the overall efficiency of the panel.
• Time of Day and Angle of Incidence. Shading during the morning or evening hours is less detrimental than shading during peak sunlight hours when the panel is generating the most power.

How Does Temperature Affect the Efficiency of Solar panels?

Higher temperatures lead to a decrease of 10-25% in efficiency which decreases the amount of electricity that solar panels can produce, according to Dr. Qusay A.H. Al-Naser, in “The Effect of Temperature Variations on Solar Cell Efficiency” study. Higher temperatures increase current and reduce voltage, this is why panels are often installed with a gap between the panel and the mounting surface to allow for better airflow and cooling. 

The optimal temperature for solar panels to work efficiently and produce the highest amount of power is typically within a moderate temperature range, between 25°C to 35°C (77°F to 95°F), according to Dr. Qusay A.H. Al-Naser. 

A solar panel’s power temperature coefficient (PTC) of is a measure of how much its power output decreases as the temperature of the panel increases, according to Dr. Swapnil Dubey, in “Temperature Dependent Photovoltaic (PV) Efficiency and Its Effect on PV Production in the World” research. Power temperature coefficient is expressed as a percentage decrease in power output per degree Celsius increase in temperature. Most solar panels have a PTC of between -0.3% and -0.5% per degree Celsius, according to  Dr. Swapnil Dubey, in “Temperature Dependent Photovoltaic (PV) Efficiency and Its Effect on PV Production in the World” research. This means that for every 1°C increase in temperature above 25°C, the power output of the panel decreases by 0.3% to 0.5%. For example, a solar panel with a power rating of 300 watts at 25°C would have a power output of 297 watts at 30°C (-1%). At 35°C, the power output would be 294 watts (-2%).

The difference in power loss, due to temperature, between different solar cells types is shown in the following chart.

How Does Sunlight Angle Affect the Efficiency of Solar Panels?

When sunlight strikes solar panels at a perpendicular angle (90 degrees), they work most efficiently. To produce efficiently, Solar panels are installed according to the latitude to be perpendicular to the sun. The optimal temperature for installing solar panels In the United States is between 30 and 45 degrees.

How Do Dirt and Dust Affect the Efficiency of Solar Panels?

Dirt and dust have negative effects on the efficiency and production of solar panels. A study by the Sandia National Laboratories found that dirt and dust decrease solar panels’ efficiency by 30%. While solar panels are designed to be durable and low-maintenance, they can still be impacted by environmental factors like dirt and dust, So it is important to know what solar panel cleaning is and how it is done

How Does Solar System’s Quality Affect the Efficiency of Solar Panels?

The overall solar system’s quality of the components, including the cells, wiring, and junction boxes, impact the panel’s long-term production and performance. Inverter Efficiency also can affect the overall efficiency of the solar energy system.