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An Enhancement of the Solar Panel Efficiency: A Comprehensive Review. Typical solar cell efficiency

An Enhancement of the Solar Panel Efficiency: A Comprehensive Review. Typical solar cell efficiency

    An Enhancement of the Solar Panel Efficiency: A Comprehensive Review

    Recently solar panels are gaining popularity in the field of non-conventional energy sources for generating green and clean electric power. On the negative side, the photovoltaic efficiency is reduced with an increase in ambient temperature. The production of energy is dropped by 0.33% for every degree Celsius above STC. Consequently, the electric power which is generated by the solar panel may not be sufficient to run the load. It is important to realize that in some applications, such as standalone electric vehicles, space for providing an additional solar panel to compensate for the decremented output power may not be feasible. By implementing the cooling arrangements, this excessive heat might be reduced. Several cooling techniques have been implemented, named as active and passive methods. This article presents a review on maximizing the efficiency of the solar panel by utilizing different cooling methods and by integrating TEG with solar panels.

    Introduction

    An abundance of innovations is transpiring to access green electricity concretely from the solar power generation sector. Conventional power generating sources such as coal and fossil fuel produce electricity with steam by the process of burning the aforementioned items. So, the research FOCUS turns toward non-conventional power generating sources such as solar, wind, tidal, and biomass energy. Among these, solar technology is most conspicuous and more developing than other sources due to its availability and clean energy (Rahman et al., 2017). Concurrently, In the photovoltaic conversion process, the operating temperature plays a vital role (Skoplaki and Palyvos 2009), and due to this, when atmospheric temperature ascends on the PV panel decreases their designated output power (Kalogirou and Tripanagnostopoulos 2006) and lags the efficiency due to bandgap shrinkage occurring during high concentration of impurities (Yildiz et al., 2017). It is possible to increase the efficiency of the PV by increasing the area of the solar panel, but it is not feasible in electric vehicles (Saleh et al., 2021). In the current review, the types of solar panels and their cooling arrangements were explained with efficiency and a review on maximizing the efficiency of the solar panel by utilizing various cooling methods such as air, water, the combination of both, phase-changing materials, fins, heatsink, nanofluids, and cotton wicks (Dwivedi et al., 2020) with solar panels were presented. Additionally, by combining Thermo Electric Generator (TEG) (Chen et al., 2017) with solar PV panels to extract energy from waste heat in PV panels (Jaziri et al., 2020) by the effect of Seebeck, the efficiency may be raised. The power from TEG aids to develop the additional electrical energy and also reduce the PV panel temperature (Makki et al., 2016). To obtain the voltage across the TEG, there is a desideratum of cooling the one side of TEG while the top side has been already heated because of Sun irradiance to the solar, which is transmitted to the TEG (Zelazna and Gołȩbiowska, 2020). Figure 1 shows the basic structure of PV cell with its output and cooling system.

    FIGURE 1. Basic structure of photovoltaic energy enhancement using a cooling system.

    In this review, Section 2 describes different solar panel efficiencies. Section 3 describes various methods to obtain the increase in efficiency without using any cooling techniques but by using devices to increase the irradiation.Section 4 describes the different cooling techniques classified as active and passive methods to increase the overall efficiency of the PV systems.

    Comparison of Efficiency for Different Solar Panels

    Solar panels can generally be classified according to the generation (Kibria et al., 2014) as first, second, and third. The initial generation has been predicated on wafer-based silicon cells, the second generation has been based on thin-film technology, and the third generation as an incipient emerging technology such as nano crystal-based, polymer-based, dye-sensitized, and perovskite-based solar cells. Figure 2 shows types of Solar cells classified according to the different parameters. Table 1 shows the comparison of different generations of cells (Guerra et al., 2018; Rathore et al., 2019; Engineering, 2018; Gaur and Tiwari, 2013).

    FIGURE 2. Basic structure of photovoltaic material.

    TABLE 1. Comparison of Efficiency with different generations of cells.

    Under the optical discernment day by day from the first generation solar panels, the monocrystalline solar panel gives a better performance compared to polycrystalline solar panel because the structure is uniform and because it is highly pure (Taşçioǧlu et al., 2016). Mostly crystalline solar cells absorb 90% of irradiance ranging from 400 to 1200 nm, but the conversion efficiency is up to 18% only while the rest are converted into heat. The PV module performance is conventionally qualified at AM1.5 with STC (Sathe and Dhoble 2017). Decrementing in efficiency per unit temperature rise is 0.4–0.5%.

    Various Methods to Enhance the Efficiency of Solar Panels

    To attain the maximum efficiency from the PV panel few additional arrangements are required, such as the Sun tracking method (Awasthi et al., 2020), concentrating mirrors (Bilal et al., 2016), and applying cooling techniques to the panels, which can be classified as active and passive cooling.

    3.1 Tracking Systems

    Solar panels are typically mounted on fixed slopes and azimuth. But to obtain maximum irradiation Sun tracking is needed. It helps maximize the incidence of the irradiation on the solar panel throughout the day which optimizes the angle at which the panel receives solar radiation (Deen Verma et al., 2020). Meanwhile, solar trackers are slightly expensive due to the moving parts and complex technology. Usually, around a 0.08. at0.10/Watts increase depends on size and location (Bushong, 2016). Tracking systems classified according to the direction of the axis are single axis and dual axis. A single-axis tracker moves the panel on one axis of movement, and, on the other hand, a dual-axis tracker moves the rotation of the panel on two axes of movement. The dual-axis tracker provides higher efficiency when compared to the single-axis tracker. According to the experiment by Dhanabal et al. (2013), the efficiency of the dual-axis tracker is found to be 81.68%, whereas the efficiency of the single-axis tracker is only 32.17% higher than the fixed panel.

    The average daily intensity per unit area using single axis and dual axis has been increased by 13.8 and 22.5%, respectively, when compared to the fixed mount. Withal the efficiency also increased by 10 and 20.7%, respectively (Hassan 2015). Rubio et al. (2007) developed an accurate Sun tracker which includes an automatic tracker and this was in the form of a hybrid system. The movement of solar is modeled by an open-loop system while the feedback controller is employed in a closed-loop system. Due to this, the motor does not consume additional energy. Taherbaneh et al. (2010) developed a fuzzy-based MPPT and it was observed that 23 W had been obtained, which was 51% of the nominal output power. In the second technique, called fuzzy-based Sun tracking, it was observed that 11 W had been approximately obtained, which was about 24.5% of the nominal output power. Then, the two above-mentioned techniques were combined. It was seen that the output power reached 78% of the nominal output power.

    According to quantum dot, solar cells can utilize high-energy photons using their potency to multiple electron-hole pairs to increment the efficiency, and additionally, double Sun solar tracking technology gives the result in a considerable increase in inefficiency. Solar Tracking system is classified according to the Drives, Axis Direction, Control and Tracking Strategies and it is shown in Figure 3. The integration of solar panels with the tracking system is utilized for position tracking of the Sun for irradiation throughout the day. Malek et al.(2012) experimented with PV panels with a tracking system and obtained the amount of voltage and current with and without tracking are tabulated in Table 2.

    FIGURE 3. Various solar tracking systems.

    TABLE 2. Voltage and current values without and with tracking.

    Sun tracking systems are conventionally classified into two categories: active trackers (electrical) and passive trackers (mechanical). Electrical-based trackers can be categorized as PC-controlled time and dated-based, auxiliary bi-facial solar cell-based, and electro-optical sensor and microprocessors-based. Mechanical trackers are based on the recollection of alloys and thermal expansion of matter (Mousazadeh et al., 2009; Ponnambalam, 2018). The efficiency obtained utilizing the Sun tracking system is incremented by 37.02%. This concentrated solar radiation and high temperature cause the solar panels to get overheated, and minimization inefficiency is unavoidable.

    3.2 Using Concentrating Mirrors

    The method to ameliorate efficiency is by utilizing concentrating mirrors with solar panel integration with sun-tracking technology. The power output decreases with the increment in temperature and vice versa (Nazar 2015). The reduction of efficiency is also due to tilt angle, dust particles (Charabi and Gastli 2013), and shadowing. For a fixed tracking system, the dust accumulation decreases with tilt angle increases (Sayyah, Horenstein, and Mazumder 2014), and at 20° from the horizontal position, PVT can produce maximum energy (Sun et al., 2016). Also, due to non-linear shading, the mismatch of short circuit current causes a loss of power (Ballal et al., 2015). Concentrated photovoltaics are unlike conventional photovoltaics, and it utilizes lenses or mirrors in a curved shape to FOCUS the sunlight onto a small area more efficiently. Commonly concentrators are an inexpensive option for increasing the efficiency of PV, which produces power in the range of 7–15 cents/Kwh depending on the size and location of the panel (Swanson 2000). Table 3 shows the voltage and current for sundry conditions (Khamooshi et al., 2014).

    TABLE 3. Voltage and current values with and without using mirrors and cooling (Arshad et al., 2014).

    From the Table 3, it is clear that when utilizing mirrors and coolants, the output power increases, also with the number of mirrors, which is approximately 52%. Quantum dot concentrators have more advantages, such as fewer problems of heat dissipation, sheets are inexpensive, and are congruous for architectural components, and it is a non-tracking property compared to other types of concentrators (Khamooshi et al., 2014). The PV panel is tilted with the inclination angle with respect to irradiation of the Sun. At the same time, there is a requirement to maintain the mirrors by cleaning them in a regular manner to attain better performance (Rahman and Khan 2010). The trough concentrated photovoltaic thermal system was experimentally studied, and the results show that the GaAs cell array gives better electrical performance than the crystal silicon solar cell arrays. But the thermal performance is inverted (Li et al., 2011).

    Different Cooling Methods to Enhance the Efficiency of Solar Panels

    PV panels absorb only the visible light for generating electrical energy (P. Kumar and Dubey 2018), and the rest of the spectrum of light is converted into heat, leading to a decrement in output performance by 0.4–0.5% per 1°C temperature rise as its standard testing conditions (Indugowda and Ranjith 2016). It is clear in the literature that the open-circuit voltage increases logarithmically with ambient irradiation, while the short circuit current is a linear function of the ambient irradiation. An increase in temperature of the cell decreases the open-circuit voltage linearly, so the solar PV panel’s efficiency is decreased. But the short-circuit current scarcely ascended with the cell temperature (Joshi, Dincer, and Reddy 2009).

    The structure of various cooling systems is shown in Figure 4, but each one of them depends on different factors such as type of PV technology, place of installation, and weather conditions (Dubey, Sarvaiya, and Seshadri 2013). Depending on the aforementioned factors, the best way to minimize the heat from the solar panel is either by using active or passive cooling systems. Inactive cooling system movable parts are present, whereas, in a passive cooling system, there are no moving parts, and efficiency-wise active cooling system is better than the passive cooling system, but not cost-wise (Kalaiselvan et al., 2018). Table 4 summarizes the PV Panels with different cooling methods.

    FIGURE 4. Various cooling methods used in PV panels to enhance efficiency.

    TABLE 4. Summary of PV with different cooling methods.

    4.1 Active Cooling System

    The active cooling system needs external electrical or mechanical energy, such as fans for air circulation and pumps for water circulation on the panels for heat dissipation (Shan et al., 2014). With the cooling water arrangement, the efficiency increases by 2% (Pradhan et al., 2017).

    4.1.1 Water Cooling Method

    M. Abdolzadeh et al. experimented by spraying the water directly to the panel, which increased the performance efficiency of PV cell, subsystem efficiency, and overall efficiency, which were 3.26, 1.40, and 1.13, respectively, when 225 WPV panel adopted with water spraying methodology with a flow rate of 644 L/h at 16 m head. The efficiency improvement was achieved by water flow at different rates.

    Ahmed AM et al. experimented with the water which flows through the tube, making holes in diameters of 2 mm diameter with a flow rate of 3, 6, and 9 L per hour, resulting in efficiencies of 8.3, 6.8, and 3.28, respectively (Ahmed and Hassan Danook 2018). So whenever a solar panel is adopted with cooling by water technology, the temperature of the panel is dropped by 4°, and performance efficiency increases by nearly 12% (Musthafa 2015). By introducing the FGM (functionally graded material) water tube systems with PV and PV-TEG, the cell efficiency increases by 30–50% and 25–40%, respectively (Yang and Yin 2011). Alberto Benato et al. also experimented with spraying technology with 1.5 bar and concluded the efficiency and power generation have increased to 13.27% and 212.31 W from 11.18% to 178.88 W, respectively (Benato et al., 2021). The merit of the water cooling method on the upper surface of the PV module is an increase in surface input radiation due to refraction in the water layer (Odeh and Behnia 2009).

    To decrease the space of PV module v-trough is utilized with CPV system, with buried water heat exchange system as active cooling. Due to that, temperature has been decremented prosperously from 72.5°C to 47.2, 45.5, 41.8, and 39.3°C at flow rates of 0.01 kg/s, 0.02 kg/s, 0.03 kg/s, and 0.04 kg/s, respectively (Elminshawy et al., 2019). Figure 5 shows the structure of the water cooling method. Generally, water has high thermal conductivity and high carrying capacity than air (Moharram et al., 2013). In industrial development sectors, the utilization of water cooling methods is more effective as the heat exhauster, and it can be used as process heat, thereby curbing some expenses (Hasanuzzaman et al., 2016). The loss of efficiency due to temperature can be minimized by utilizing the water spray method also. S. Nizetic et al. additionally experimented with the spray water method on the 50 W solar panels and achieved the truncation of temperature between the non-cooled and cooled cases (Nižetić et al., 2016).

    FIGURE 5. ooling method by a water channel.

    4.1.2 Air Cooling Method

    The structure of the air cooling method is shown in Figure 6. Under high irradiation conditions, the performance of cooling the PV panel by forced convention (either air or water) is better than natural convection, and up to 15% efficiency gain and temperature reduction are achieved (Mazón-Hernández et al., 2013). Amori et al. experimented with the PV with a flat plate collector at a constant air velocity of 0.0091 kg/s, and they obtained a reduction of temperature of 15.52°C with a single-pass air channel to the PV system (Amori and Adil Abd-AlRaheem, 2014). The mass flow rate plays a consequential role in solar panel cooling by decrementing the outlet temperature of the channels and tubes (Othman et al., 2016).

    FIGURE 6. ooling method by an air channel.

    4.2 Passive Cooling System

    It covers all the natural processes and techniques of heat dissipation and modulation without any external sources. The combination of photovoltaic and thermal collectors called PV/T has plenty of advantages over standalone PV, such as occupying lesser space (Al-Waeli et al., 2016), lesser economic payback period, wastage of heat is collected by a solar collector who is in the same area behind the PV. The PV/T collectors transfer heat from the PV cells, which are absorbed from the Sun into a fluid, thereby cooling the cells and thus improving their efficiency. In this way, this excessive heat is serviceable and can be utilized to heat water or used as a low-temperature source for heat pumps. The dissipated heat energy from PV panels can be utilized in different ways and can aid in obtaining additional energy. In the PV thermal system, to exhaust the heat, different components are used, such as air collector, water collector (Besheer et al., 2016), nanofluids (Sardarabadi and Passandideh-Fard, 2016), thermoelectric generators (Greppi and Fabbri 2021), and phase-changing materials (Rao, Reddy, and Rao 2020) to improve the efficiency.

    4.2.1 Comparative of Parameters With and Without Fins

    The transfer of heat from the Sun to the PVT has to be minimized by the cooling method, which was discussed above, and additionally, this heat dissipation is enhanced by utilizing fins.

    Apart from various heat abbreviation methods, which are discussed earlier, another type of cooling method is by introducing the fins in the PV panel’s rear side so that the heat is radiated through the fins to the atmospheric temperature (Cuce, Bali, and Sekucoglu 2011). The overall performance of PVT is higher than the sum of the performance of solar panels alone and solar thermal systems (Van Helden et al., 2004). Figure 7 shows the V-I and P-V characteristics using fins and without fins. A.M. Elbreki et al. demonstrated one of the passive cooling with lapping fins at solar irradiance of 1000 W/m 2. and the PV module has given better output efficiency of 10.68% at 24.6°C lower than the ambient temperature of 33°C (Elbreki et al., 2021). The voltage and current values with a combination of fins and PV panels are tabulated below in Table 5.

    FIGURE 7. V-I and P-V characteristics with and without fins.

    TABLE 5. Voltage and current values with and without the contribution of fins.

    4.2.2 Nanofluids Based Coolants

    When acetone is kept as a refrigerant in micro-channel heat pipes under vacuum conditions, the instantaneous electrical efficiency is 7.6%, thermal efficiency is 54% (Verma and Kumar Tiwari 2015), and the electrical gain of PVT-MHP ascends from 17 to 74 W under irradiation between 367 and 787 W/m 2 (Modjinou et al., 2017). Utilizing nanofluids such as Al2O3–water and silicon carbide (SiC)–water as a coolant to the lower concentration PVT system gives a significant decrement in temperature in the PV module, particularly at the high concentration ratio and Reynolds number (Radwan, Ahmed, and Ookawara 2016). Mohammad Sardarabadi et al. experimented with different coolants such as PVT/Water, PVT/ZnO, PVT/TiO2, and PVT/Al2O3, and the efficiency was enhanced by 12.34, 15.45, 15.93, and 18.27%, respectively (Sardarabadi et al., 2017). On the other hand, the main demerit of using nanofluids is that they have limited time stability. The completion of a heat exchanging channel using water with nanofluid as coolants have higher electrical efficiency compared to that of base fluid (Karami and Rahimi 2014).

    Figure 8 shows the voltage generated from TEM utilizing different coolants at 12.30 PM. Sio2/water coolant is the most efficient coolant, which provides the highest temperature gradient (Soltani et al., 2017). The total energy rise will be 48 W when utilizing 3 wt% of Ferrofluid under an alternating magnetic field in a thermal collector integrated with a PV panel (Ghadiri et al., 2015).

    FIGURE 8. TEM produced voltage for different coolants.

    4.2.3 PCM Based Heat Sinks

    Phase Changing Materials (PCM) are usually contained in three different containers, namely grooved, tubed, and finned. T. Wongwuttanasatian et al. chose palm wax as a heat sink and analyzed it with a PV panel which resulted in a decrease in temperature from 57.9 to 51.8°C, the performance of PV cell was incremented by 5.3%, and the performance ratio was incremented by 4.8% (Wongwuttanasatian, Sarikarin, and Suksri 2020). J.G. Hernandez-Perez et al. designed a 3D model heat sink that has multidirectional airflow. This new design has the potential to be cost-effective by optimizing the dimensions needed to enhance the performance of the photovoltaic system that is affected by high temperature (Hernandez-Perez et al., 2020). Tan et al. used an aluminum heat sink in a concentrated PV with an average of 10 pores density and 0.682 porosity of aluminum foam. It gave the best enhancement inefficiency of the solar panel by removing the heat (Tan et al., 2019). Figure 9 shows the surface temperature of the PV panel with different nanofluids. Arifin et al. experimented with the CPV panel with aluminum (phase-changing material) and visually examined the results, in which the temperature ascended due to the concentrated panel, decremented from 85.3 to 72.8°C, and the output was also increased by 18.7% (Arifin et al., 2020).

    FIGURE 9. Surface temperature in Celcius for different phase-changing materials (Hosseinzadeh, Sardarabadi, and Passandideh-Fard, 2018; Kazemian et al., 2018; Lee et al., 2019)

    Another passive cooling method of PVT was introduced by M. Chandrasekar et al. Chandrasekar et al. (2013) used a cotton wick structure with a combination of water. The output power was increased from 41 W to 47.5 and 44.6 with a combination of cotton wick–water and cotton wick–nanofluid, respectively. In summary, by comparing all other cooling methods, the nanofluid PVT system has higher heat transfer characteristics because of higher thermal conductive characteristics (Hamzat et al., 2021).

    4.2.4 Thermo Electric Generators

    In the recent developments of performance enhancement of PV modules, thermoelectric generators have a significant impact on the performance of the photovoltaic system. The heat transfer from the PV array by conduction method and heat transfer from the CO2 layer by convection method is used to increase the heat transfer towards TEG hot side to obtain maximum efficiency (Koushik et al., 2018).

    Thermoelectric generators are devices that convert heat energy into electrical energy by the effect of Seebeck. It is similar to a thermocouple with the difference that the thermoelements are made up of semiconductors p and n, and heat is applied to the hot side and heat is removed from the cold side, both the junctions being made of copper. TEG Integrated with a PV panel will enhance its performance and minimize the amount of heat dissipation (Sahin et al., 2020). The output of a TEG generally varies non-linearly with the temperature since the properties of thermoelectric materials vary non-linearly with the temperature (Bjørk and Nielsen 2015).

    Temperature distribution should be punctilious from PV to TEG. An open-circuit voltage of photovoltaic–thermal hybrid solar-generator had been ascended by 1.3% when compared to that of a PV panel working alone (Mizoshiri, Mikami, and Ozaki 2012), and it contributed about 10% output power in a hybrid system (Ju et al., 2012). In PVT-TEG, the concentrator type of thermal collector has given good performance due to the high accumulation of heat at one point (Lin, Liao, and Lin 2015). The thermal efficiency of the thermoelectric generator depends on the difference in temperature across its modules (between the hot and cold surfaces). The thermal design of the thermoelectric system plays a vital role in ensuring that there exists a maximum temperature difference across the hot and cold surfaces of the TEG (Karthick et al., 2018). An opportune design of heat recirculation through the thermoelectric generator may result in maximum conversion efficiency (Min Gao and Rowe, 2007).

    The performance of the PV-TEG is not identical to the individual performance of PV and TEG alone because the heat abstraction increases the efficiency of PV and optimal location, and TEG numbers give the maximum efficiency individually (Babu and Ponnambalam 2017). The operational structure of PV-ST-TEG is shown in Figure 10, with attention to a few elements such as (Bi 2Te 3) at room temperature 9 K (acting as the cold side) and lead telluride (PbTe), which is at 500–600 K (acting as the hot side) have been identified as the thermoelectric materials. These thermoelectric materials have a quantification called the figure of merit. That is, the above-mentioned materials have a metric of measure that avails to evaluate the thermoelectric properties. The higher concentration ratio of the TEG results in higher power production due to the absorption of heat flux. H. Hashim et al. examined the photovoltaic cell with TEG in an ambient atmosphere, it reduces the power output from the solar module due to the increment in operating temperature due to large thermal resistance across TEG, but it is compensated by TEG output. In an integrated PV/T solar system, the thermal efficiency descends with ascending temperature, and it also causes a decrement in power generation efficiency (Hashim et al., 2016). Ali Salari et al. examined the performance of PVT and PVT with a thermal electric generator and attained the electrical efficiency of PVT-TEG incremented by 10.41% at STC. When inlet fluid temperature increases to 34°C from 26°C, the electrical efficiency decreases by 2.58 and 4.56% for PVT and PVT-TEG, respectively. Similarly, for the temperature variation from 26°C to 34°C, the electrical efficiency of PVT and PVT-TEG is 1.43% decremented and 0.82% incremented, respectively. The flat plate PVT operates at 100–200°C at the absorber surface, whereas the concentrated PVT operates at 800°C, which produces more heat when compared to the flat plate (Salari et al., 2020). Figure 9 shows the design structure of a photovoltaic system combined with solar thermal collectors. The combination of TEG with solar thermal and photovoltaic modules is termed a PV hybrid system (Babu and Ponnambalam 2017). The life of the PV cell is ameliorated as the thermodynamic constraints are decreased. The efficiency of the solar module also ascends based on the magnitude of thermal energy abstracted from the surface area of the module. From the difference in TEG between the hot and cold sides, the PV panel can reach 17% of efficiency with a contribution of 3% from TEG (Zulakmal et al., 2019).

    FIGURE 10. perational structure of PV-ST-TEG.

    The efficiency performance of solar panels alone in the amalgamated Solar-TEG system is 9.39%, and the combined efficiency is 13.8% (Wang et al., 2011). The efficiency obtained by the thermoelectric device in terms of the dimensionless figure of merit called ZT is broadly used to access the desirability of thermoelectric materials for devices and used to characterize the performance of a device such as their relative utility for an application (Kim et al., 2015). It grows with the square of the Seebeck coefficient. The TEG efficiency is resolute by the thermoelectric figure of merit (z) = α2/ρk, where ρ is electric resistivity, k is thermal conductivity, and α is the thermo emf coefficient of the TEG material (Vorobiev et al., 2006). The ascending temperature leads to the decrement of efficiency due to bandgap shrinkage, results in voltage drop, and the PV cell temperature is given by TPV = TA cG (Raut, Shukla, and Joshi, 2018).

    A phase-changing material can be introduced between PV and TEG to obtain an efficiency of 26.57% from the single PV system efficiency of 25.55% (Cui, Xuan, and Li 2016). Shen and Mason (2020) experimented with PV with TEG outdoor under direct Sun and observed that the reduction of heat due to the TEG in PV panel leads to maximizing the output power by 2.5% from the average efficiency.

    Ahiska et al. (2016) compared the power generated from a PV panel and TEG and obtained the experimental results, and as the power generated from a thermoelectric panel is 30 times greater than a PV panel, they have experimented with a 1 m 2 surface area of PV and TEG panels, the thermoelectric panel produces 4kw while the PV panel produces only 132 w. The thermoelectric materials can be divided into three groupings according to the temperature range (Rowe 1999), for lower temperatures up to 177°C, alloy-based bismuth in cumulating with antimony, tellurium, or selenium. For medium temperatures around 580°C, alloy-based lead (Pb), and higher temperatures, SiGe alloys are utilized to 1,025°C (Ismail and Ahmed 2009). For solar photovoltaic cells, the lower temperature range materials are preferred. In that case, Bismuth Tellurium can be used as a thermoelectric material. A 40 mm 40 mm 3.4 mm TEG has a thermal conductivity of 2 W/m-K, a density of 7,790 kg/m 3. and specific heat of 250 J/Kg-K (Rohit et al., 2017). Zhang et al. (2020) designed PV with monocrystalline and TEG made by bismuth telluride with adhesive of thermal interface materials; the results show that the PV generation increases by 14% and TEG by 60% because of a decrement in thermal contact resistance. The enhancement of heat transfers between PV and TEG has been done by thermal interface materials. PV-TEG can be coupled in two ways, as shown in Figure 9, one is direct coupling, and another is spectrum splitting coupling [96]. In the direct method, the TEG is connected directly to the PV to generate the additional energy, while in the spectrum splitting coupling method, the energy is transmitted to PV at below 2,500 nm cut-off wavelength and TEG at above 2,500 nm.

    Figure 11 shows the direct and indirect coupling of PV-TEG. Photovoltaic module gets solar irradiation through the optical concentrator significantly improves the overall efficiency, which is very promising for PV efficiency improvement (Hajji et al., 2017). A higher concentration level on the PV panel results in higher output power in TEG, but this causes a reduction in the efficiency of the PV panel due to high temperature (Zhang et al., 2014). Najafi and Woodbury (2013) have experimented with combined PVT-TEG with 36 TEG modules which have produced 145 W by PV panel and 4.4 W by TEG modules with 2.8 suns solar irradiance. Photovoltaic panels with concentrating mirroring technology give output power with a lesser number of solar panels compared to the normal requirement to produce the same output power, and this technology has the advantage of having a reduced payback period while utilizing Reflectors (Wijesuriya et al., 2017).

    FIGURE 11. PV–TEG with (A) Direct and (B) Indirect coupling (optical concentrator).

    Necessity of Building-Integrated PV

    Building-integrated photovoltaic (BIPV) systems are replacing conventional building materials in parts of the building envelope such as the roof, skylights, and facades or embedded into the building structure (Strong 2016). Depending on the solar cell, about 6–16% of the incoming solar irradiation is converted into electricity, and the rest of the irradiation is transmitted as heat or reflected. A PV module obstructs the solar radiation on the original wall in BIPV/T installations. BAPV (building applied PV) systems installed above rooftops are limited only to the roof area, whereas systems with BIPV occupy most of the building surface area by integrating photovoltaics (Biyik et al., 2017). The solar absorptivity of a building envelope is changed when replacing/covering conventional building structures, the reflective roof, for instance, with PV modules. The use of semi-transparent PV modules changes the visible transmittance of light and subsequently the artificial lighting energy consumption profile. The BIPV method is increasingly becoming the ideal solution to be applied in urban areas (“BAPV vs. BIPV: What Are the Differences? | ASCA,” 2019).

    There are varieties of BIPV technologies that can be used in building applications. The most common ways to use BIPV in building applications are shown in Figure 12 (“Building Integrated Photovoltaics_ Pros, Cons Cost In 2022,”2022).

    FIGURE 12. Types of BIPV product type choices.

    Floating Solar Panels

    Industries use a huge number of solar modules for high generation of power. These panels are generally mounted on land space. Due to this, solar panels occupy a lot of space. So, an alternative is needed to save the area. The PV panels have been mounted on floating areas such as dams, reservoirs, lakes, and oceans (Patil, Wagh, and Shinde, 2017). The installation has been made by many countries in Africa, Asia, and Japan due to the low availability of land (Yousuf et al., 2020).

    Floating solar module installation is an eco-friendly method. It has more advantages such as reduced shading, water evaporation, and algae growth and improved water. Some disadvantages are expensive installation and limited application of usage. The first floating solar system was installed at Napa California in 2007, it contains 1,000 panels as floated and linked with 1300 stationary panels on land. From this arrangement nearly 4 MW can be produced. Table 6 (“Solarserver | Das Internetportal Für Erneuerbare Energien,” 2020; Kumar 2021; “South East Asia’s First Floating Solar Farm,” 2013.; France 2012) illustrates various floating solar plants projects developed worldwide.

    TABLE 6. Various floating solar module installation stations around the world.

    Future Scope of Efficiency Enhancing

    Various methods were discussed earlier to increase the efficiency of the PV panel. To enhance the efficiency further, some of the research gaps were identified to carry out needful research.

    1) Materials such as copper or aluminum have to be integrated behind the PV panel so that the heat extraction is uniformly distributed in all TEGs.

    2) The overall solar conversion efficiency was 40% (Zhang et al., 2012). The MPPT algorithm has to be implemented for PV and TEG in a combined algorithm.

    3) With the heat sinks, the active or passive cooling method has to be added so that the temperature difference may increase. Hence, the output of TEG will increase.

    4) Through active cooling technologies, the flow of air, water, or any fluid increases due to external force, which dramatically increases the rate of heat reduction, whereas, through passive cooling technologies, the rate of flow of the coolants is naturally convected.

    5) Passive thermal management is a cost-effective and energy-efficient solution which uses heat sinks and thermoelectric generators to maintain optimal operating temperatures and is used to generate nano electrical energy from the heat transfers. TEGs can decrease the temperature of PV panels by transferring to the cold side, and due to the temperature gradient, the electrical energy can be produced by it. For any PV installation, passive methods can be referred to cool the panels because they are cost-effective.

    Conclusion

    In this article, the types of solar panels and their cooling systems were explained with efficiency. It has been concluded that

    1) The efficiency of solar PV panels can be increased by applying tracking systems and by placing mirrors to concentrate the radiation from the Sun. However, the above-mentioned techniques increase the temperature with the light radiation, and, hence, the purpose of tracking and concentration are de-merited due to an increase in heat.

    2) To decrease the heat, different cooling methods under active and passive classifications were discussed, such as air, water, a combination of both, nanofluids, phase-changing materials, and heatsinks, and also the different efficiencies of solar PV cells were obtained depending on the above-mentioned cooling techniques.

    3) Withal thermoelectric generators are utilized as a passive method to convert the heat energy into electrical energy and integrate the efficiency with the photovoltaic cell. This method is integrated with PV and called PVT-TEG, obtaining the additional electrical energy with the decrement of heat from the solar panel. Also, from the above-mentioned cooling methods, a few can be applied to the TEG on the cold side so as to obtain adequate electrical energy to be integrated into the photovoltaic cell.

    4) This review presents a methodology to increase the efficiency of solar PV panels without occupying any additional area; the efficiency can be improved by using TEG and cooling methods. If it is implemented in the given area, we can utilize this for solar-operated conveyances because the main drawback of the solar panel is the occupation of the area for the production of the requisite quantity of electrical energy.

    Author Contributions

    Both authors contributed to content preparations and validation of context.

    Conflict of Interest

    The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

    Publisher’s Note

    All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors, and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

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    Keywords: photovoltaic module, active and passive cooling, phase changing materials, heat sink, PV-TEG-heat sink

    Citation: Parthiban R and Ponnambalam P (2022) An Enhancement of the Solar Panel Efficiency: A Comprehensive Review. Front. Energy Res. 10:937155. doi: 10.3389/fenrg.2022.937155

    Received: 05 May 2022; Accepted: 23 June 2022; Published: 14 July 2022.

    Haochun Zhang, Harbin Institute of Technology, ChinaShashank Vyas, Softbank Energy, IndiaYashwant Sawle, Madhav Institute of Technology Science Gwalior, India

    Copyright © 2022 Parthiban and Ponnambalam. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    This article is part of the Research Topic

    Solar Photovoltaic System to Meet the Sustainable Development Goals

    Solar Cell I-V Characteristic and the Solar Cell I-V Curve

    The Solar Cell I-V Characteristic Curves shows the current and voltage ( I-V ) characteristics of a particular photovoltaic ( PV ) cell, module or array. It gives a detailed description of its solar energy conversion ability and efficiency. Knowing the electrical I-V characteristics (more importantly Pmax ) of a solar cell, or panel is critical in determining the device’s output performance and solar efficiency.

    Photovoltaic solar cells convert the suns radiant light directly into electricity. With increasing demand for a clean energy source and the sun’s potential as a free energy source, has made solar energy conversion as part of a mixture of renewable energy sources increasingly important. As a result, the demand for efficient solar cells, which convert sunlight directly into electricity, is growing faster than ever before.

    Photovoltaic ( PV ) cells are made made almost entirely from semiconductor silicon that has been processed into an extremely pure crystalline material which absorbs the photons from sunlight.

    The photons hit the sillicon atoms releasing electrons causing an electric current to flow when the photoconductive cell is connected to an external load. For example, a battery. There are a variety of different measurements we can make to determine the solar cell’s performance, such as its power output and its conversion efficiency.

    The main electrical characteristics of a PV cell or module are summarized in the relationship between the current and voltage produced on a typical solar cell I-V characteristics curve. The intensity of the solar radiation (insolation) that hits the cell controls the current ( I ), while the increases in the temperature of the solar cell reduces its voltage ( V ).

    Solar cells produce direct current ( DC ) electricity and current times voltage equals power, so we can create solar cell I-V curves representing the current versus the voltage for a photovoltaic device.

    Solar Cell I-V Characteristics Curves are basically a graphical representation of the operation of a solar cell or module summarising the relationship between the current and voltage at the existing conditions of irradiance and temperature. I-V curves provide the information required to configure a solar system so that it can operate as close to its optimal peak power point (MPP) as possible.

    Solar Cell I-V Characteristic Curve

    The above graph shows the current-voltage ( I-V ) characteristics of a typical silicon PV cell operating under normal conditions. The power delivered by a single solar cell or panel is the product of its output current and voltage ( I x V ). If the multiplication is done, point for point, for all voltages from short-circuit to open-circuit conditions, the power curve above is obtained for a given radiation level.

    With the solar cell open-circuited, that is not connected to any load, the current will be at its minimum (zero) and the voltage across the cell is at its maximum, known as the solar cells open circuit voltage, or Voc. At the other extreme, when the solar cell is short circuited, that is the positive and negative leads connected together, the voltage across the cell is at its minimum (zero) but the current flowing out of the cell reaches its maximum, known as the solar cells short circuit current, or Isc.

    Then the span of the solar cell I-V characteristics curve ranges from the short circuit current ( Isc ) at zero output volts, to zero current at the full open circuit voltage ( Voc ). In other words, the maximum voltage available from a cell is at open circuit, and the maximum current at closed circuit. Of course, neither of these two conditions generates any electrical power, but there must be a point somewhere in between were the solar cell generates maximum power.

    However, there is one particular combination of current and voltage for which the power reaches its maximum value, at Imp and Vmp. In other words, the point at which the cell generates maximum electrical power and this is shown at the top right area of the green rectangle. This is the “maximum power point” or MPP. Therefore the ideal operation of a photovoltaic cell (or panel) is defined to be at the maximum power point.

    The maximum power point (MPP) of a solar cell is positioned near the bend in the I-V characteristics curve. The corresponding values of Vmp and Imp can be estimated from the open circuit voltage and the short circuit current: Vmp ≅ (0.8–0.90)Voc and Imp ≅ (0.85–0.95)Isc. Since solar cell output voltage and current both depend on temperature, the actual output power will vary with changes in ambient temperature.

    Thus far we have looked at Solar Cell I-V Characteristic Curve for a single solar cell or panel. But a photovoltaic array is made up of smaller PV panels interconnected together. Then the I-V curve of a PV array is just a scaled up version of the single solar cell I-V characteristic curve as shown.

    Solar Panel I-V Characteristic Curves

    Photovoltaic panels can be wired or connected together in either series or parallel combinations, or both to increase the voltage or current capacity of the solar array. If the array panels are connected together in a series combination, then the voltage increases and if connected together in parallel then the current increases.

    The electrical power in Watts, generated by these different photovoltaic combinations will still be the product of the voltage times the current, ( P = V x I ). However the solar panels are connected together, the upper right hand corner will always be the maximum power point (MPP) of the array.

    The Electrical Characteristics of a Photovoltaic Array

    The electrical characteristics of a photovoltaic array are summarised in the relationship between the output current and voltage. The amount and intensity of solar insolation (solar irradiance) controls the amount of output current ( I ), and the operating temperature of the solar cells affects the output voltage ( V ) of the PV array. Solar cell I-V characteristic curves that summarise the relationship between the current and voltage are generally provided by the panels manufacturer and are given as:

    Solar Array Parameters

    • VOC = open-circuit voltage – This is the maximum voltage that the array provides when the terminals are not connected to any load (an open circuit condition). This value is much higher than Vmp which relates to the operation of the PV array which is fixed by the load. This value depends upon the number of PV panels connected together in series.
    • ISC = short-circuit current – The maximum current provided by the PV array when the output connectors are shorted together (a short circuit condition). This value is much higher than Imp which relates to the normal operating circuit current.
    • MPP = maximum power point – This relates to the point where the power supplied by the array that is connected to the load (batteries, inverters) is at its maximum value, where MPP = Imp x Vmp. The maximum power point of a photovoltaic array is measured in Watts (W) or peak Watts (Wp).
    • FF = fill factor – The fill factor is the relationship between the maximum power that the array can actually provide under normal operating conditions and the product of the open-circuit voltage multiplied by the short-circuit current, ( VOC x ISC ) This fill factor value gives an idea of the quality of the array and the closer the fill factor is to 1 (unity), the more power the array can provide. Typical values are between 0.7 and 0.8.
    • %eff = percent efficiency – The efficiency of a photovoltaic array is the ratio between the maximum electrical power that the array can produce compared to the amount of solar irradiance hitting the array. The efficiency of a typical solar array is normally low at around 10-12%, depending on the photovoltaic type (monocrystalline, polycrystalline, amorphous or thin film) of cell being used.

    Solar Cell I-V Characteristic Curves are graphs of output voltage versus current for different levels of insolation and temperature and can tell you a lot about a PV cell or panel’s ability to convert sunlight into electricity. The most important values for calculating a particular panels power rating are the voltage and current at maximum power.

    Some solar panels are rated at slightly higher or lower voltages than others of the same wattage value, and this affects the amount of current available and therefore the panels MPP. Other parameters also important are the open circuit voltage and short circuit current ratings from a safety point of view, especially the voltage rating. An array of six panels in series, while having a nominal 72 volt (6 x 12) rating, could potentially produce an open-circuit voltage of over 120 volts DC, which is more than enough to be dangerous.

    Photovoltaic I-V characteristics curves provide the information needed for us to configure a solar power array so that it can operate as close as possible to its maximum peak power point. The peak power point is measured as the PV module produces its maximum amount of power when exposed to solar radiation equivalent to 1000 watts per square metre, 1000 W/m 2 or 1kW/m 2.

    For more information about Solar Cell I-V Characteristic Curves and how they are used to determine the maximum power point of a photovoltaic cell or panel, or to explore the advantages and disadvantages of using solar panels as an alternative energy source, then why not Click Here and order your copy from Amazon today and learn more about the fun and easy way to get a grip on photovoltaic design and installation.

    Solar Panel Efficiency in 2023

    Solar panel efficiency measures how well solar panels are able to convert sunlight into usable electricity.

    Thanks to advances in technology, solar panel efficiency has steadily improved over time. As a result of this increase in the current solar panel efficiency, you can get the same amount of power with fewer panels on your roof, or more power with the same number of solar panels.

    This article will explain what solar panel efficiency means, how the average efficiency of solar panels affects power production, the role high-efficiency solar panels play in the clean energy transformation, and more.

    What Determines Solar Panel Efficiency?

    Your solar panel’s ability to produce energy by converting the sunlight it receives to usable electricity depends upon five crucial factors: materials, wiring, reflection, age, and temperature.

    enhancement, solar, panel, efficiency, comprehensive

    Impact of Materials on Solar Panel Efficiency

    Solar panel manufacturers use different substances to create different types of solar panels, including:

    • Polycrystalline silicon
    • Monocrystalline silicon
    • Cadmium telluride
    • Multi-junction solar cells

    Each solar panel material helps determine how much sunlight will be converted to electricity. Most manufacturers today use monocrystalline silicon solar cell technology for their panels because of their superior efficiency. Monocrystalline photovoltaic (PV) cells are more efficient than other panel types because they are made from a single crystal of silicon, which means electrons can move more easily through the cell.

    In addition to existing solar panel materials like silicon, solar companies are exploring other materials that could deliver even more efficient panel technology, including both organic and more recyclable options. (We have a deeper discussion of these developments below.)

    Impact of Wiring on Solar Panel Efficiency

    Solar panels can be wired in series and in parallel, and the different wiring configurations have an impact on how your solar panel system will function and how much power it can produce. There are advantages and disadvantages to each option, so it’s one of the decisions a solar panel company will make when designing the ideal solar power system for your home.

    Wiring also helps determine the right inverter for your solar arrays, whether it’s a string inverter, power optimizer, microinverter, hybrid inverter, or something else entirely. The type of inverter that is used–especially in terms of how power is collected from the panels and sent to your house, battery storage, and electricity grid–can impact your solar panel system’s overall efficiency.

    Within the panels themselves, wiring and “busbars” (the metal connecting solar cells in the solar panel that actually captures and transfers electricity) have an effect on efficiency, with more efficient panels using different configurations and different technologies to improve this process.

    Impact of Reflection on Solar Panel Efficiency

    The amount of light reflected away from a solar cell’s surface impacts solar panel efficiency. Solar panel efficiency depends on the amount of light they can absorb and convert into electricity.

    If light reflects off the surface of the panel, it can’t become electricity, which lowers the efficiency of that panel. Solar power panels with textured surfaces and anti-reflection coatings can help minimize the amount of light that gets reflected away.

    Impact of Age on Solar Panel Efficiency

    The average lifespan of solar panels is about 25 to 30 years. Throughout this period, your solar system should generate all the electricity you need to power your home, unless the panels get blocked by too much shade, dirt, or other debris.

    However, during that 25- to 30-year timeframe, your panel efficiency will slowly decrease over time, until they eventually reach a point where the solar panels don’t create enough electricity for all of your home’s needs. This degradation rate is factored into the initial design of a solar power system, but it still impacts your solar panel’s efficiency.

    Impact of Temperature on Solar Panel Efficiency

    The climate of your area impacts solar panel efficiency, as the energy levels of electrons are determined by their level of excitement. Contrary to what you might think, solar panels are more efficient at lower temperatures. Because the electrons on the thin layer of silicon are calmer and less excited, they can move with greater ease and increased numbers through the transmission lines to generate solar power.

    When it is hot, the electrons are more excited and moving in different directions. This makes it more challenging for them to move effectively through the transmission lines, leading to lower solar energy production levels during a hot day.

    In other words, you will experience higher voltage and enhanced generation efficiency during a cold sunny day compared to a hot sunny day.

    How To Calculate Solar Panel Efficiency

    The easiest way to calculate the efficiency of your solar panels is with this formula:

    Efficiency (%) = (Pmax ÷ Area) ÷ (1000) x 100%

    • Pmax = max solar panel power (in Watts)
    • Area = length x width of the solar panel (in m2)
    • 1000 = Standard Test Condition (STC) irradiance

    Let’s break it down a bit for deeper comprehension.

    Find your panel’s max power capacity

    You can find this information labeled as Pmax or maximum power on the spec sheet for your solar panels.

    Get your panel’s physical dimensions

    The standard panel dimensions are 65 inches by 39 inches, but you can also find and verify this information for your own panels–specifically, length and width–on the specification sheet.

    Calculate the power unit area of your panel

    To get the power unit area of your module, divide its Pmax into its area.

    Factor in the STC

    Standard Test Condition (STC) represents the ideal environment used by solar manufacturers when testing average solar panel output. These conditions include a cell temperature of 25 °C and air mass of 1.5, and solar irradiance of 1000 W/m2. That value of 1000 W/m2 is what’s used in the efficiency equation.

    Calculate solar panel efficiency

    Using some sample numbers, we can walk through the math. Assuming your solar panels are 2 m2 in area, produce 400 watts, and receive 1,000 W/m2 of sunlight, the efficiency of your solar panels is 20%.

    Efficiency (%) = (400 ÷ 2) ÷ (1000) x 100%

    Solar Panel Efficiency in 2023

    The average solar panel efficiency in 2023 ranges from 15% to 20%. At the high end, the most efficient solar panels available for public use achieve 22% efficiency.

    While the majority of solar panels available in the United States today are below 20% efficiency, we can anticipate that the efficiency of solar energy systems will continue to improve as the solar industry pursues advanced photovoltaic technology.

    History of Solar Panel Efficiency

    The first major breakthrough in solar power was made by Alexandre-Edmond Becquerel in 1839. He discovered the photovoltaic effect, the root of the modern solar cell. Since then, solar innovation and improvement have remained a FOCUS for the scientific community and the solar industry as they look to improve solar panel efficiency and increase energy output over time.

    Below is a brief synopsis of major advances in solar energy efficiency over the last three decades, courtesy of new solar panel technology.

    • 1992: The University of South Florida manufactures a 15.89% efficient thin-film cell
    • 2012: Solar Frontier achieves 17.8% efficiency
    • 2015: First Solar CdTe thin film technology reaches 18.6% efficiency
    • 2015: SolarCity hits 22.04% efficiency
    • 2015: Panasonic’s 72-cell prototype achieves 22.5% efficiency
    • 2015: SunPower attains 22.8% efficiency with its X22 panel
    • 2016: The Swiss Center for Electronics and Microtechnology and the National Renewable Energy Laboratory achieve 29.8% efficiency
    • 2016: The University of South Wales researchers attain 34.5% efficiency
    • 2017: George Washington University and Naval Research attain a 44.5% solar cell efficiency
    • 2018: Research into perovskite reveals a theoretical upper limit of 66% efficiency

    To be clear, a majority of these high efficiency ratings of the most efficient solar panels are achieved in a laboratory setting, and aren’t yet possible at a commercial scale due to high production costs.

    The National Renewable Energy Laboratory has been tracking the increase in research-cell efficiencies for a variety of solar panel technologies, and it shows the continued stair-step of improvements over time:

    Solar panel efficiency over time has come a long way, thanks to the relentless efforts of solar panel manufacturers and scientists. These continual improvements in solar panel efficiency are great for the environment because they reduce our reliance on electricity created from fossil fuels and send even more energy to the grid. The clean energy they produce helps reduce our reliance on fossil fuels and also helps us combat greenhouse gas emissions.

    Why are Modern Solar Panels Efficient?

    There are two main reasons why modern solar panels are more efficient: advances in research and the materials used.

    Solar Power Research

    The desire to improve solar power efficiency drives the development of new solar panel technology, as these significant breakthroughs to improve solar energy systems continue in solar research centers across the globe.

    Leading research facilities like the National Renewable Energy Laboratory and The Swiss Center for Electronics and Microtechnology use their resources, technologies, and expertise to conduct experimental studies that help develop the high-output solar panels of the future.

    Improvements To Materials

    Silicon has been the preferred semiconductor material for generating solar energy, and manufacturers have used silicon for decades because solar cells fabricated from it are low-cost, high-efficiency, and long-living.

    Solar panel researchers continue to find new ways to increase the effectiveness of silicon, including the creation of ultra-thin crystalline layers, enhanced production processes that remove silicone dust from solar cells, and next-generation growth methods. These modern techniques have resulted in the dramatic solar efficiency improvements we discussed earlier in the article.

    Beyond silicone, ongoing experimentation with more efficient materials like perovskite, and the incorporation of various solar technologies in the design process have combined to create the potential for even more highly efficient panels in the future.

    Comparing Cost and Value to Rate Efficient Solar Panels

    The average current solar panel efficiency ranges from 15% to 20%, but if you wish to install more efficient panels, you should be ready to pay more.

    When designing a solar power system, consider the cost-benefit tradeoff between the higher price of more efficient panels and the amount of additional energy they create before you make that investment. It might be more economical to just install a few more lower-efficiency panels, compared to upgrading all panels to a higher efficiency to produce the same amount of power.

    Because most customers buy panels that are 15% to 20% efficient, most manufacturers still produce a majority of their panels in that normal efficiency range. However, some circumstances may warrant the installation of high-efficiency solar panels, such as limited roof space or a complicated roof layout.

    Roof Space

    The space on your roof can impact the number of panels that can be installed. If that space can’t fit the number of lower-efficiency panels required to generate enough power for your needs, solar installers may use more efficient panels at an extra cost.

    Roof Layout

    The design of your roof also determines the number of residential solar panels your home needs, and how they can be positioned. For example, if the area of your roof with more space isn’t angled to receive much sunlight, the area with less space will be considered. This could result in a custom layout for your solar panels which could increase your budget.

    If you have a complex roof layout, Palmetto can work with you to determine the solar panel system design that will generate the electricity you need.

    The Future of Solar Panel Efficiency

    Various research centers are working to increase solar panel efficiency by experimenting with new materials such as organic photovoltaics, concentration photovoltaics, and quantum dots. Manufacturers are also incorporating exciting new technologies that drive the industry forward, including:

    • Building-integrated PV panels
    • Perovskite solar cells
    • Floating solar farms (floatovoltaics)
    • Solar skins
    • Solar fabric

    Floating solar farms are being deployed worldwide, and studies show that in utility-scale settings they can produce more electricity compared to ground-mounted or rooftop installations, thanks to the cooling effects of the water that boost their efficiency. The application of building-integrated PV and solar skins also demonstrates that the future of solar power efficiency is looking bright.

    How To Improve the Efficiency of Your Solar Panels

    Solar panels are designed to run efficiently without the homeowner needing to do anything. However, you can help ensure your panels are reaching their maximum efficiency by engaging in two simple chores:

    • Keep shade off your solar panels
    • Clean your panels regularly (Learn more about Solar Panel Cleaning)

    You can also help detect possible issues with the efficiency of your solar panel system by tracking its performance through a mobile app like the Palmetto App and enrolling in a routine maintenance service like Palmetto Protect. If the performance of your panels has deteriorated, Palmetto can advise you on steps you can take to generate the electricity your home needs.

    Key Takeaways

    Increasing the average efficiency of solar panels remains a key driver of developments in the solar panel industry. Improvements to efficiency is good news for everyone involved in the New Utility Revolution, as it means we can power our homes and businesses with more of the sun’s rays and fewer fossil fuels.

    Since solar panel efficiency depends upon materials, wiring, reflectivity, age, and temperature, researchers pursue every possible lead to enhance those factors so that more electricity can be generated more effectively.

    At Palmetto, we use some of the most efficient solar panels in the market to maximize your solar production. We know that saving money on your utility bills and helping to save the planet is important to you, which means we’ll help you create the best possible solar panel system for your home.

    Interested in adding efficient solar panels to your roof? Learn how much you could be saving with our Estimate Savings Tool today!

    The Best Ways to Maximize Solar Panel Efficiency

    Energy efficiency is an important factor to consider as you shop for home solar panels, but what does energy efficiency mean? We’re here to help you make sense of solar panel efficiency, and we’ll help you maximize it so you can get the most out of your home solar system.

    Want an industry-leading solar system for as little as 0 down? Schedule a solar consultation with one of our expert Solar Advisors today.

    How Efficient Are Solar Panels?

    To determine solar panel efficiency, sometimes referred to as photovoltaic conversion efficiency, we measure how much energy from sunlight is transformed into electricity. 1 The average commercial solar panel converts 17-20% of sunlight into electricity. 2 While 20% might not sound like a lot, it’s enough to keep the average American home powered throughout the day. Even the best semiconductors only capture a fraction of the light that strikes them. 3 Much of the light that strikes solar panels is reflected back, passes through the panel, or is converted into heat instead of electricity. 3 That’s why the residential solar panels you often see appear dark blue or black. 4 These “anti-reflection” coatings ensure the solar panels absorb as much sunlight as possible to maximize efficiency. 4

    Do Solar Panels Degrade over Time?

    As with most technologies, solar panels will naturally produce less energy over time. This reduced power output is called the degradation rate. The median solar panel degradation rate is about 0.5%, which simply means that a solar panel’s energy production will decrease at a rate of 0.5% per year. 5 After 20 years, your panels should still be working at about 90% of its original output.

    While solar systems typically last upwards of 20 years, repairing and replacing a solar energy system can come at a high cost. 6 When you lease a solar system with Sunrun, all you have to do is pay for the power—we’ll take care of the rest. Our solar lease includes free system monitoring, maintenance, and repairs so you can enjoy 25 years of worry-free, clean energy.

    How Does Weather Affect Solar Panel Efficiency?

    Even in below-freezing weather, solar panels turn sunlight into electricity. That’s because solar panels absorb energy from our sun’s abundant light, and not from the sun’s heat. In fact, cold climates are actually optimal for solar panel efficiency. 7 As long as sunlight is hitting a solar panel, it will generate electricity. Less output during the winter months will primarily be due to shorter daylight hours, or possibly heavy snow.

    This doesn’t mean that solar panel output will decrease in warmer weather; any diminished efficiency is balanced out thanks to more daylight hours during the spring and summer months. 7

    Do Solar Panels Work in Rain and Snow?

    If your winters look cloudy, rainy, snowy, or all of the above, not to worry. Solar panels can still generate electricity under these conditions, too. While solar panels are most productive in direct sunlight, they can still use diffuse or indirect sunlight (radiation) to generate energy. 8

    Even though energy production decreases with increasingly dense Cloud cover, panels continue working to a greater capacity than one may expect. Rain also helps wash away dust on panels to keep them operating efficiently. 9

    During times of heavy snow accumulation, solar panels’ dark, reflective glass accelerates snow melt so that it slides off before it can hamper performance. Rooftop solar panels are also typically tilted up at 30 to 45 degrees, which keeps snow from accumulating, but only to a point. 11 In comparison, a light dusting of snow is likely to blow off or disappear rapidly.

    In fact, on cold, clear days, snow from the ground can reflect extra sunlight onto your solar panels like a mirror. This “albedo effect” enables panels to produce even more electricity in the cold. 10

    If your panels require more than a routine hosing down or require you to get on the roof, we highly urge you to contact a trusted solar provider to receive professional assistance.

    Three Tips on Maintaining Solar Panel Efficiency

    While solar panels generally require little maintenance, it’s still important to inspect your solar panels from time to time and monitor their performance. Here are a few tips to ensure your solar installation is working at its full capacity: 12

      Keep your panels clear of debris and other damaging materials. While rain is generally sufficient to keep your panels clean, you may want to consider a professional cleaning if you ever notice your panels aren’t working at their full capacity.

    Energy Efficiency vs. Cost Efficiency

    While solar panel efficiency is important to consider, cost efficiency will likely be the most relevant factor in your search for a home solar panel system. Sunrun ensures you have a cost-efficient system in three ways:

      We only recommend solar if it has the potential to save you money. Sunrun will help you determine whether a solar panel system has the potential to cut the cost of your current electricity rates. Our easy-to-use Product Selector will ask you for your average monthly electricity bill so our Solar Advisors can determine if solar makes financial sense for you.

    Renewable Energy and Efficient Solar Panels for Your Energy Needs

    A reputable residential solar company will guarantee reliable solar panel production and dependable customer service for decades to come. With over 20 years of experience, Sunrun is committed to creating a clean energy future for all.

    See why over 600,000 Americans across the country have partnered with Sunrun and get a solar consultation today. You can also use our easy Product Selector to get a solar system that’s custom-fit to meet your needs.

    • 1. Photovoltaic Energy Factsheet
    • 2. Solar Energy Optics: expanding efficiency
    • 3. Solar panels are more efficient than you’ve heard. This material could make them even better.
    • 4. Solar Performance and Efficiency
    • 5. Lifetime of PV Panels
    • 6. How Much Do Solar Panels Cost?
    • 7. How Does Temperature Affect Solar Panels?
    • 8. Direct, Diffuse and Reflected Radiation
    • 9. Just a spoonful of solar panel cleaning, helps the revenue go up – the revenue go up!
    • 10. Solar Panels Work Great In Snowy Regions, Research Shows
    • 11. Let it Snow: How Solar Panels Can Thrive in Winter Weather
    • 12. How Much Does It Cost To Clean And Maintain Solar Panels?
    • 13. Short-term Energy Outlook

    Top 5 Most Efficient Solar Panels (2023 Reviews)

    This guide has helped many homeowners learn about solar panel efficiency and can help you make the right choice when deciding on the most efficient option. Let’s get started!

    Each product and or company featured here has been independently selected by the writer. You can learn more about our review methodology here. If you make a purchase using the links included, we may earn commission.

    Written by Karsten Neumeister

    Karsten is an editor and energy specialist focused on environmental, social and cultural development. His work has been shared by sources including NPR, the World Economic Forum, Marketwatch and the SEIA, and he is certified in ESG with the CFA Institute. Before joining EcoWatch, Karsten worked in the solar energy sector, studying energy policy, climate tech and environmental education. A lover of music and the outdoors, Karsten might be found rock climbing, canoeing or writing songs when away from the workplace. Learn About This Person

    Reviewed by Melissa Smith

    Melissa is an avid writer, scuba diver, backpacker and all-around outdoor enthusiast. She graduated from the University of Florida with degrees in journalism and sustainability studies. Before joining EcoWatch, Melissa worked as the managing editor of Scuba Diving magazine and the communications manager of The Ocean Agency, a nonprofit that’s featured in the Emmy award-winning documentary Chasing Coral. Learn About This Person

    Why You Can Trust EcoWatch

    We work with a panel of solar experts to create unbiased reviews that empower you to make the right choice for your home. No other site has covered renewables as long as us, which means we have more data and insider information than other sites.

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    What Are the Most Efficient Solar Panels?

    A solar panel’s efficiency rating tells you how much of the solar energy that hits your panels will be converted into usable electricity for your home. It’s not the only measure of a high-quality solar (PV) panel, but it’s one of the most important ones. Higher efficiency ratings mean your panels will generate more power in all conditions—full sun, partial sun and cloudy weather—which directly correlates to greater energy savings for you.

    We’ve looked at every top-rated major solar panel brand and the panel models offered and have determined that the below panel brands have the highest efficiency ratings in the solar industry.

    • Maxeon (formerly SunPower): Most Efficient Panels
    • LONGi Solar: Best Value
    • Jinko Solar: Best Budget Brand
    • Canadian Solar: Best Product Selection
    • REC: Best Availability

    Not all of the panels manufactured by these companies have the same efficiency rating, and some models fluctuate by a few percentage points. Below are the specific models from each manufacturer we found to be the most efficient. Note that there’s a drop-down menu available for each of these brands in case you’re looking for more information.

    Sunpower

    The Maxeon 6 AC line of panels from Maxeon—which used to be SunPower—is best known for having the highest efficiency rating of any solar panel ever manufactured at 22.8%. Maxeon has been around for more than 35 years and has long had a reputation for outstanding quality and industry-defining technology. We recommend these panels to all homeowners who can afford them. They’re expensive, but they lead to the greatest savings over time and come with one of the best warranties available.

    What We Like

    The Maxeon 6 line of panels not only have the highest efficiency rating available, but they also now come with a massive 40-year equipment and production warranties, topping any other company we looked into. The standard in the clean energy industry is 25 years of coverage for production and manufacturer defects, and Maxeon offers 40 years of protection for both. That means ultimate peace of mind that your panels will continue performing as expected for decades.

    Maxeon and its sister company, SunPower, are also known for their commitment to quality customer service, so we expect that any warranty claim you do make will be honored.

    Lastly, for those who care about the appearance of these panels, these are all black without grid lines, so they’re about as sleek as you can get.

    What We Don’t Like

    The only bad thing we have to say about these Maxeon panels is that they’re more expensive than most other options. We do feel that the quality of the panels is well worth the investment, but they could be prohibitively costly for some solar customers.

    Solar Panel Options

    Maxeon currently manufactures two different lines of solar panels, both with inverters supplied by Enphase: the Maxeon 6 panels (AC) and the Maxeon 3 panels (DC).

    • Maxeon 6 panels: As mentioned above, these panels have the highest efficiency rating in the industry at 22.8%. They generate the most power in all conditions of any other panel, and they’re backed by an incredible 40-year warranty. The 6 is a slightly more efficient solar panel than the 3.
    • Maxeon 3 panels: Maxeon 3 panels have efficiency ratings up to 22.7%, but depending on the size of the panel you choose, that could be as low as 21.2%. The larger panel sizes come with the same 40-year warranty, but the smaller ones have the industry standard 25-year warranty.

    Warranty Information

    All Maxeon panels come with at least 25 years of coverage for manufacturer defects and performance, but all of the Maxeon 6 panels and some of the Maxeon 3 options include the company’s 40-year warranty. This covers manufacturer defects and related issues, and it guarantees that your panels will retain 88.3% of their original efficiency in year 40. This coverage is far superior to the industry standard 25-year warranty.

    Installation Options

    Maxeon is going through some changes and is working on making its sister company SunPower its exclusive installer. However, SunPower currently outsources installation to certified third-party solar companies. There are local installation companies that are able to install Maxeon panels in all 50 states.

    LONGi Solar

    Founded in 2000, LONGi is the largest solar panel manufacturer in the world, with a market capitalization nearly triple that of any competitor. Not only is LONGi one of the most successful manufacturers, but it also manages to provide outstanding value at below-average costs. The Hi-Mo 6 Scientist panels from LONGi deliver top-of-the-line efficiency ratings, and although the warranty isn’t quite as good as other panels, the upfront savings you’ll see more than make up for it, in our opinion.

    What We Like

    The Hi-Mo 6 panels reach efficiencies of 22.6%, nearly matching the industry leader. That means LONGi solar panels will help bring down your energy bills more than most other brands on a monthly and annual basis. Best of all, LONGi panels cost around 2.40 per watt, which is well below what other brands at this efficiency rating and quality cost.

    LONGi panels have a low power tolerance, which is a measurement of expected power production differential in real-world situations. The industry average is.5%/5%, and the Hi-Mo 6 Scientist model boasts a.3%/3% differential. That means you’ll see a lower production rate fluctuation, ultimately helping to maximize your energy savings over time.

    What We Don’t Like

    LONGi panels don’t have the best warranty coverage, which is really the only major downside to the brand. The Hi-Mo 6 Scientist panels come with only a 15-year warranty for manufacturer defects, whereas the industry standard is 25 years. The power production guarantee does meet the standard 25-year coverage, although the expected remaining efficiency rating after that time (88.9%) is a bit lower than some other brands that guarantee 92%.

    Solar Panel Options

    LONGi’s most recent innovation, the Hi-Mo 6 line of panels, is phasing out the Hi-Mo 4 and Hi-Mo 5 product lines. There are four different options within the new Hi-Mo 6 lineup.

    Efficiency Rating Panel Type Estimated Cost Per Watt Power Warranty Best For
    Hi-Mo 6 Scientist Up to 22.6% Monocrystalline 2.40 580W to 590W 15 to 25 years Maximum efficiency
    Hi-Mo 6 Explorer Up to 22.1% Monocrystalline 2.40 560W to 570W 15 to 25 years Extreme climates
    Hi-Mo 6 Guardian N/A Monocrystalline 2.40 N/A 15 to 25 years Self-optimization
    Hi-Mo 6 Artist N/A Monocrystalline 2.40 N/A 15 to 25 years Unique appearance

    Warranty Information

    Of the manufacturers with the highest panel efficiencies, LONGi is the least impressive. It covers manufacturer defects for 15 years compared to the 25-year standard. The power production warranty—which helps ensure you continue to save money on your electric bills—is for the industry standard of 25 years. However, it guarantees 88.9% efficiency at the end of the warranty term, whereas other companies guarantee 90% or more.

    Installation Options

    Unlike Maxeon, LONGi doesn’t have any specific partnerships, so its products are widely available and can be installed by any solar contractor that chooses to offer them.

    Jinko Solar

    Jinko Solar is another giant in the industry that provides panels across the globe. It’s best known as a budget brand, although its panels are still considered to be tier-one. We recommend Jinko panels to solar customers who want to keep upfront installation costs down but still get a high-quality brand with an above-average efficiency rating. Much like LONGi, Jinko’s panel warranties aren’t the best.

    What We Like

    Jinko Solar’s size makes its products widely available throughout the U.S. Without any specific partnerships, its panels are available from hundreds of installers in every state. The average cost per watt for Jinko panels is around 2.25, making it the most affordable high-efficiency solar panel brand on our list.

    Despite the low cost, Jinko panels are ranked quite high by PV Evolution Labs (PVEL), suggesting that the panels outperform many other brands in a variety of conditions. With a peak efficiency rating of 22.6%, Jinko’s panels are likely to boost your energy savings over less efficient options, all while saving you money on your installation.

    What We Don’t Like

    The biggest downside to Jinko Solar’s panels is the warranty coverage. Its performance warranty lasts the standard 25 years, but the degradation in the first year (2.5%) is higher than the industry average of around 2%. Plus, the remaining efficiency at the end of the term is just 80.7%, compared to the typical ~90% in other high-quality brands. The manufacturer’s warranty of 12 years also pales in comparison to the standard 25 years.

    Solar Panel Options

    Jinko currently manufactures three panel models in its Eagle lineup for U.S. customers: the Eagle G5, the Eagle G4 and the Eagle Continental. There are two additional product lines for other countries—Cheetah and Tiger—which are expected to come to the U.S. after testing.

    Efficiency Rating Panel Type Estimated Cost Per Watt Power Warranty Best For
    Eagle G5 Up to 21.13% Monocrystalline 2.40 525W to 545W 12 to 25 years Efficiency for U.S. Customers
    Eagle G4 Up to 20.96% Monocrystalline 2.40 380W to 400W 12 to 25 years Value
    Eagle Continental Up to 19.88% Monocrystalline 2.25 380W to 400W 12 to 25 years Budget Panels in U.S.
    Tiger Neo Up to 22.6% Monocrystalline 2.40 475W to 635W 12 to 25 years High Efficiency Rating
    Cheetah Up to 20.16% Monocrystalline 2.25 355W to 410W 12 to 25 years Budget Panels Outside of U.S.

    Warranty Information

    Jinko Solar has decent warranty coverage, but it’s not ideal compared to what industry leaders like Maxeon are able to offer. Jinko provides just a 12-year warranty for the equipment and manufacturer defects, which is less than half of the industry average. The power performance warranty lasts for 25 years, which is average, although the solar degradation in that time — close to 20% — is double what you’d see from higher-quality panels.

    Installation Options

    As one of the world’s largest manufacturers, Jinko doesn’t have any specific partnerships with installers. Any solar panel installation company that chooses to install Jinko panels can do so without any specific certification. That means you should have a wide selection of installers available to you if you specifically want Jinko panels.

    Canadian Solar

    Canadian Solar is a large international manufacturer that has been in business since 2001, so it has more than 20 years of experience. Its products provide an outstanding blend of quality and affordability, although the average price per watt is a little above average. We’d recommend Canadian Solar panels to homeowners looking to balance power output with affordability.

    What We Like

    Canadian Solar not only manufactures one of the highest-efficiency panel models available, but it also provides budget options—specifically, polycrystalline solar panels with a lower efficiency. This helps keep solar as accessible as possible, which we love to see from any manufacturer.

    The warranty coverage available for newer models is all in line with the industry standard in terms of length, so you should get decades of useful life and energy savings out of the company’s products.

    Finally, Canadian Solar offers more than just panels. It serves other manufacturers with raw materials that help speed up the production and increase quality of off-brand products, as well as keep industry costs down. Overall, the company has a positive impact on the solar space.

    What We Don’t Like

    The warranty coverage for everything other than the new HiHero product lineup isn’t up to the industry standards. The HiHero panels come with an above-average 30-year performance warranty plus the typical 25 years of coverage for things like manufacturer defects. The efficiency remaining after the warranty term is below average, though, at 84.8%. Most other models only come with a 15-year equipment warranty, but they do have the standard 25-year coverage for equipment issues.

    Solar Panel Options

    Canadian Solar has a pretty impressive lineup of panels that fall within two product lines: the HiKu line and the HiHero line.

    Efficiency Rating Panel Type Estimated Cost Per Watt Power Warranty Best For
    HiKu Up to 19.4% Polycrystalline or Monocrystalline 2.70 360W to 465W 12 to 25 years Affordability
    BiHiKu Up to 20.1% Polycrystalline or Monocrystalline 2.70 435W to 460W 12 to 25 years Affordability
    HiHero Up to 22.5% Heterojunction (HJT) 3.20 420W to 445W 25 to 30 years High Efficiency
    Hiku 6 Up to 21.3% Monocrystalline 2.90 445W to 555W 12 to 25 years Balancing Efficiency and Price
    BiHiKu 6 Up to 21.4% Monocrystalline 2.90 520W to 550W 12 to 25 years Balancing Efficiency and Price
    HiKu 7 Up to 21.6% Monocrystalline 3.00 640W to 670W 12 to 25 years Small Roofs
    BiHiKu 7 Up to 21.4% Monocrystalline 2.90 640W to 665W 12 to 25 years Small Roofs
    TOPHiKu 6 Up to 21.4% TOPCon Cell 2.90 420W to 570W 12 to 25 years Balancing Efficiency and Price
    TOPBiHiKu 6 Up to 21.4% TOPCon Cell 2.90 555W to 575W 12 to 25 years Balancing Efficiency and Price
    TOPBiHiKu 7 Up to 21.4% TOPCon Cell 2.90 615W to 695W 12 to 30 years Small Roofs

    Warranty Information

    If you purchase the highest-efficiency panels from Canadian Solar—the HiHero model—you get a standard 25-year product warranty plus a 30-year power production guarantee. The degradation is more significant in these panels than average at this price point, but the warranty length is still better than most companies offer.

    Other models come with a 12-year product warranty, which is less than half of what most other manufacturers provide. Most come with a 25-year production warranty—again with a faster rate of efficiency degradation than average—except for the TOPBiHiKu 7 model, which gets a 30-year efficiency warranty.

    Installation Options

    Canadian Solar doesn’t have any specific partnerships with U.S. installers, so its products are available in most areas from a massive selection of contractors. Plus, Canadian Solar is one of the few manufacturers with a vertical product line, which means its high-efficiency solar cells and other products make their way into off-brand panels. You could, therefore, end up with Canadian Solar technology even if you don’t specifically buy panels from the company.

    REC Solar

    REC is a solar manufacturer based in Norway with a massive presence throughout the U.S. By the company’s own statistics, it is the largest provider of photovoltaic (PV) modules to the United States, which is, in large part, why we think REC has some of the best solar panel availability in the country. Not only are its products widely available, but the company maintains above-average efficiency ratings across all of its products. We recommend REC panels to homeowners who want easily accessible options that will help maximize energy savings over time.

    What We Like

    REC’s performance specs and availability make it a go-to option for countless installers in the U.S., which means its products are available virtually anywhere you live. The company uses heterojunction (HJT) technology to keep panel efficiency high, which means REC panels save you more on energy bills than the average PV equipment.

    REC’s warranty coverage is also quite good, with a 25-year power production warranty guaranteeing 92% of the original efficiency at the end of the warranty term for most panel models. That’s in line with other top performers in the industry.

    REC panels also have a great temperature coefficient, losing just 0.26% efficiency per degree (C) above 25 degrees (77 degrees in Fahrenheit). That means REC panels are a great option for maintaining those high efficiency ratings and energy savings even in more extreme climates.

    What We Don’t Like

    The only real downside to REC panels is that they’re a bit on the expensive side. The high-end models cost around 3.20 per watt, before any solar tax credit is considered. The cheaper options with less impressive specs average as low as 2.50 per watt, though, so the company maintains options that will be suitable for most solar customers.

    Solar Panel Options

    REC has five primary product lines available that do a good job of providing something for everyone. This is yet another reason why we think REC is one of the most widely accessible brands in the industry.

    enhancement, solar, panel, efficiency, comprehensive
    Efficiency Rating Panel Type Estimated Cost Per Watt Power Warranty Best For
    Alpha Pure-R Up to 22.3% Heterojunction (HJT) 3.20 410W to 430W 25 years High Efficiency
    Alpha Pure Up to 21.6% Heterojunction (HJT) 3.20 385W to 410W 25 years Warranty Coverage
    N-Peak 3 Up to 20.3% Monocrystalline 2.80 390W to 400W 20 to 25 years Balancing Efficiency and Cost
    N-Peak 2 Up to 20.3% Monocrystalline 2.80 360W to 375W 20 to 25 years Balancing Efficiency and Cost
    TwinPeak 4 Up to 20.5% Monocrystalline 2.50 360W to 375W 20 to 25 years Affordability

    Warranty Information

    For the top-of-the-line products, including the Alpha Pure and Alpha Pure-R series, REC provides a 25-year warranty for the equipment, production and labor in case a panel needs to be serviced. All other products include a 20-year equipment warranty, which is just below the industry average, and a 25-year production warranty, which is right in line with the average term.

    However, the company guarantees 92% efficiency will remain after the efficiency warranty term, which is better than most companies and in line with the best options in the solar space.

    Installation Options

    The best part about REC, in our opinion, is that it’s one of the top producers of panels in the U.S. Without being beholden to a single installer, just about any solar contractor can install REC panels, meaning the products should be available regardless of where you live.

    REC does offer a superior warranty if you have your panels installed by a REC-certified installer, so keep that in mind if you know you do want REC panels.

    What Should You Look for When Choosing High-Efficiency Solar Panels?

    Aside from your installer making sure your solar system is sized properly for your home and energy consumption, choosing high-efficiency panels is the best way to maximize your solar savings and ensure you don’t end up paying for a solar array and a high monthly electric bill.

    However, it’s not as simple as picking the panel with the highest efficiency rating. There are a few other things to consider that could change which option is actually best for your particular home. The infographic below includes a quick look at some of the most crucial things to think about that contribute to how well solar panels work in real-world conditions as opposed to standard testing conditions in a lab.

    Compare the Top-Rated High-Efficiency Solar Panels

    Overall, our top recommendations if you’re looking for high-efficiency panels are the Maxeon 6 panels from Maxeon and the Alpha Pure-R panels from REC. You might notice that our second pick actually has the fifth-highest efficiency, and that’s because we considered other crucial factors like degradation rate warranty coverage.

    The table below includes some additional information about these two panel models to help you decide which of these is the right option for your solar project. We’ll also include info for our top panel recommendation from the other providers on our list for comparison.

    Efficiency Rating Power Output Temperature Coefficient (per degree C over 25) Power Tolerance First-year Degradation Subsequent-year Degradation Efficiency After 25 Years Total Warranty Term (for Efficiency)
    Maxeon 6 Up to 22.8% 410W to 440W -0.29% 0/5% 2% 0.25% 92% 40 years
    LONGi Hi-Mo 6 Scientist Up to 22.6% 580W to 590W -0.29% 0/5% 1.5% 0.5% 86.5% 25 years
    Jinko Solar Tiger NEO Up to 22.6% 475W to 635W -0.29% 0/3% 1% 0.4% 89.4% 30 years
    Canadian Solar HiHero Up to 22.5% 420W to 445W -0.26% 0/10% 1% 0.55% 85.8% 30 years
    REC Alpha Pure-R Up to 22.3% 410W to 430W -0.26% 0/5% 2% 0.25% 92% 25 years

    Compare the Top-Rated High-Efficiency Solar Panel Manufacturers

    As far as the best manufacturers overall for high-efficiency panels, we’d have to choose Maxeon again as our number one recommendation, although our second spot goes to LONGi. All of Maxeon’s panel models come with superior warranty coverage, reliability and durability, and LONGi is a great low-cost option that still brings plenty of value for the money.

    The table below includes a side-by-side look at the product lines as a whole from these providers and the others that topped our list. We’ll include scoring for each based on our methodology, which will be explained in greater depth later in this article.

    Efficiency Score (Out of 25) Durability Score (Out of 20) Warranty Score (Out of 20) Price Point Score (Out of 20) Temperature Coefficient (Out of 10) Sustainability Score (Out of 2.5) Appearance Score (Out of 2.5) Our Overall Rating (Out of 100)
    Maxeon 25.0 19.0 20.0 6.0 10.0 1.9 2.25 84.1
    LONGi 25.0 11.5 11.0 20.0 10.0 1.25 1.25 80.0
    Jinko Solar 22.5 7.5 11.0 20.0 10.0 0.625 0 71.6
    Canadian Solar 20.5 7.5 16.0 10.0 7.0 1.9 1.5 64.4
    REC 25.0 13.0 16.0 10.0 7.0 1.9 1.8 74.6

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