Solar panels are one of the most important tools in the energy transition that is happening. It is not news anymore that burning fossil fuels leads to serious environmental issues like global warming; instead, it’s a fact. Therefore, environment-friendly alternatives such as solar panels for energy generation are getting more popular.

The efficiency rate of solar panels ranges between 15 to 22 %. The solar panels with better efficiency generate more energy output and consume less space on your roof. Experts are determined to increase the efficiency of solar panels to replace conventional resources of energy production completely.

Commercial buildings like Google’s headquarters use these panels to generate their total energy. Solar panels can also regulate remote power systems, remote sensing, and telecommunication equipment. However, we must overcome many challenges before getting to higher efficient solar panels.

What is a solar panel?

The energy coming from the Sun in the form of solar irradiance is captured and directly converted into electricity using photovoltaic (PV) technology. A solar panel comprises a series of photovoltaic cells (composed of semiconductors) arranged into a panel forming a photovoltaic system. This system absorbs sunlight and converts it into electrical energy used to power businesses or local authority-owned properties.

A substantial increase in solar installations has been observed on an industrial scale and in public buildings like schools and hospitals. Moreover, solar farms composed of millions of solar panels are powerful enough to generate electricity for large urban populations.

Solar cells absorb photons of light from the Sun and convert them directly into electrical energy through a phenomenon termed the photovoltaic effect. Solar panels also store excess energy onto the main power grid used to produce power during nighttime when there is no Sun.

The essential components of off-grid solar applications include an inverter, charge controller, and battery bank. The inverter is responsible for converting this direct current (DC) into the alternating current (AC), which can be used for non-DC applications. The AC helps to generate power in recreational boats and vehicles, remote traffic controls, remote cabins, oil and gas flow monitoring, telecommunications equipment, SCADA, RTU, etc.

Factors affecting the efficiency of solar panels

The performance of the PV system is negatively affected by many environmental and natural factors. Natural factors include cloud, soil dust on the panels, salt, snow, temperature, bird droppings, etc. Additionally, factors like orientation, placement, the pitch of the roof, panel design, and shade also impact these systems’ efficiency. The semiconductors used in the PV system, followed by a loss of a significant amount of solar energy due to reflection, make solar panels less efficient.

How efficient are solar panels as compared to other energy sources?

The world energy demand is directly related to the increasing population; thus, more energy is needed to fulfill the needs of millions of people. Different energy sources (renewable and non-renewable) are being used in other parts of the world to meet this energy demand. The IEA (2020) report data showed that about 79% of total energy in the US and 84% of total energy worldwide is through fossil fuels.

The energy production through solar PV showed a growth rate of 23% from 2019 to 2020. About 3.1 % of the energy was generated using sunlight, making it the third-largest renewable energy source after water and wind energy in 2019. Although other sources produce a more significant amount of electricity, they are more expensive or cause pollution when compared to solar PV sources. This data indicated the gap between solar panels and other energy resources.

Also, we should keep in mind that researchers have indicated that we are most likely to run out of fossil fuels by the year 2300. Therefore, we should improve renewable and environment-friendly energy sources like solar energy. It should be noted that solar panels’ efficiency is still lower compared with other energy resources like coal, wind, and nuclear (as shown in the table below). However, significant measures are being taken to incorporate new technologies and improve photovoltaic technology.

The efficiency of solar panels in 2021

National Renewable Energy Laboratory (NREL) reported that the efficiency of most of the solar panels manufactured in 2021 ranges from 15% to 20%. Some of the most advanced systems employed at an industrial scale show more than 20% efficiency, which is a great success. Some of the highly efficient solar systems of 2021 are presented below:

The efficiency of solar panels in 2022

The solar panels in 2022 are almost as efficient as last year. However, the efficiency of solar panels showed a substantial increase in the past decade. Initially, in 1954 the solar panels showed an efficiency of 6%, which raised to 13.4% by 2011. It shows that today’s development of solar panels with 22% efficiency is worth celebrating. The most efficient panels are termed premium panels and are very costly compared to less efficient ones.

How to increase solar panel efficiency?

The solar cells are most likely to absorb visible light and reflect infrared and UV rays, resulting in the loss of efficiency. If solar cells are made capable enough to absorb infrared rays, it will increase efficiency. Solar panels should be durable enough to sustain high temperatures without getting overheated.

The protective coverings should be high-quality and reflect minimum light, which will increase energy production. Multifunctional thin films and panels with self-cleaning, anti-fogging, and anti-reflection properties enhance solar panels’ surface properties, making them efficient.

The solar panels should be oriented towards the direction of the Sun to increase overall efficiency. The efficiency of solar PV could decrease by 100% with just 5 cm of snow deposit. Therefore, it is essential to either tilt the panels to remove snow, or remove it manually. Solar panels with higher efficiency (around 20%) use costly materials like N-type cells with the least light-induced degradation. Thus, using high-quality material help increase efficiency and is most suitable for spaces with limited surface area.

Dust and bird dropping reduce the efficiency of solar panels; therefore, self-cleaning superhydrophobic surfaces are a good alternative. It includes methods like vapor-assisted coating, polymerization, and powder coating. Other forms of fabricating the solar panel coatings include superhydrophilic, superhydrophobic, and photoactive coating surfaces.

Recent innovations in solar panel technology

Flexible solar panels

These panels are specifically designed for curved surfaces (like tents, curved roofs) and low-light areas. Flexible solar panels are cheaper and easier to install than the standard panels but have lower efficiency in full sunlight. They have an efficiency of between 7% to 15%, and high-end flexible solar panels are almost as efficient as standard panels. These bifacial panels with monocrystalline cells allow light to pass through to the back of the panel and capture extra rays of light. The construction of airflow beneath these panels would help to make them more efficient without overheating.

Transparent solar cells

Unlike normal solar cells (which only absorb visible light), these solar cells can absorb invisible light (infra-red and ultraviolet). It is an exciting innovation, but transparent solar cells are only 10% efficient. However, researchers are continually trying to overcome the challenges and increase the efficiency of these inexpensive solar cells.

Autonomous Cleaning Bots

To address some of the challenges of soiling and dust there are some innovative technologies that involve autonomous cleaning of solar panels. One such solution is Airtouch which provides a water-free robotic cleaning solution that may increase solar energy output up to 30% through automatic cleaning routines. This also helps to save labour costs on manual cleaning of solar panels.

Solar monitoring and analytics

Another promising category of technology is from data: solar analytics. There are solutions that are rapidly developing that get generation data from the solar panels/inverters to understand the operational performance of the solar system. These platforms collect the data and compare the performance between the strings, panels, and the system as a whole between each other and also across time taking weather data such as irradiance and humidity into account.

One such solution is Precinto which is an India based startup that has won multiple awards through its realtime platform to help improve operations, predict failures, and identifying early alerts on underperforming sections of the solar system.

Conclusion

Sunlight is an efficient energy source if captured efficiently. Solar panels are getting renowned as people become more aware of fossil fuels’ adverse consequences. Solar PV systems have gotten more efficient in the past ten years. The high-tech and premium solar panels should be made accessible and affordable. There is a need for further research and innovation to increase the efficiency of solar panels. Some latest technologies like transparent solar cells and flexible panels seem promising. However, there is still a long way to acquire solar panels as efficient as fossil fuels.  

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