The efficiency of a solar panel is the ratio of energy generated by the cell to the amount of energy received from the sun.

The efficiency is determined by not only the performance of the solar cell, but also on the spectrum and intensity of solar radiation striking it, as well as its temperature.

The text below is the calculation of solar cell efficiency.

Solar Cell Efficiency Calculation

The fraction of incident power that is converted to electricity and is called the solar cell’s efficiency:




Voc is the open-circuit voltage;

Isc is the short-circuit current;

FF is the fill factor and

η is the efficiency.

The input power for efficiency calculations is 1 kW/m2 or 100 mW/cm2. Thus the input power for a 100 × 100 mm2 cell is 10 W and for a 156 × 156 mm2 cell is 24.3 W.

Related: What’s the Difference Between a Solar Cell and a Solar Panel?

How To Increase Solar Panel Efficiency

Another approach to boost the effectiveness of your solar array is to use micro-inverters. A conventional string inverter receives power from the entire installation as a whole, whereas micro inverters are linked to each solar panel separately.

This means that if one panel is in the shade, it doesn’t affect the others. Inverters also have a maximum power point (MPP) tracker, which ensures that each panel always operates at its optimal efficiency, regardless of how much sunlight it is receiving.

Related: Solar Advantages and Disadvantages

Increasing solar panel efficiency with mirrors

The most basic and efficient method of light reflection is to employ mirrors. The performance of the PV panel system improves when light is reflected over the solar panel by reflecting it again over the solar panel.

Factors Affecting Solar Panel Efficiency

  • Temperature.
  • Energy Conversion Efficiency.
  • Solar Shadings.
  • The Orientation, Inclination, Latitude of the place and Climatic conditions.


Solar panels are tested at 77°F and shown to function at peak efficiency between 59°F and 95°F. Solar panels, on the other hand, can reach as high as 149°F during the summer.

When your solar panel’s surface temperature surpasses 150 degrees Fahrenheit, their performance may be reduced.

Energy Conversion Efficiency

The solar module’s spectral response varies with the type of the module. As a result, variations in spectral irradiance impact solar power production. The incident light reflection is reduced to improve energy conversion efficiency.

Solar Shadings

Solar Shade could be reducing as much as 40% of the solar potential of your property.

This is due to the fact that as a shadow falls over a panel, the amount of sunshine reaching the ground is reduced.

Changing the output of your PV modules by that much could make a significant difference in the economics of your solar investment.

The Orientation, Inclination, Latitude of the place and Climatic conditions

The orientation of the solar module is fixed in most cases. The latitude of the site has an impact on the angle of incidence, which affects solar power production.

Climatic conditions also affect solar power production. For example, if it is cloudy, the amount of sunlight reaching the ground is reduced.

Solar panels are most efficient when they are perpendicular to the sun’s rays. The angle of incidence, or the angle at which sunlight hits a PV panel, affects the amount of electricity produced by the panel.

The angle of incidence is determined by the latitude of the site and the orientation of the panel. The optimum angle of incidence for a PV panel is equal to the latitude of the site.

Maximum Power Of Solar Cell Formula

When the differential of the cell’s power is zero, the maximum voltage occurs. V t = n k T q to simplify notation in the derivation, where kT/q is 0.026 volts and n is the ideality factor.

Maximum Efficiency Of Solar Cell

Solar cells developed with a new material have an efficiency of 44.5 percent, making it potentially the world’s most efficient solar cell. The average conversion efficiency of solar energy is presently around 25%.

Related: The Promises And Challenges Of Perovskite Solar Cells

Solar Panel Efficiency Over Time

The degradation rate of solar panels is the speed at which their efficiency degrades over time, and it is an unavoidable side effect of exposure to the elements. According to a 2012 National Renewable Energy Laboratory study, solar panels lose 0.5 percent to 0.8 percent of their output capacity each year as they age.

Power Conversion Efficiency Formula

Efficiency is defined as the ratio of output watts to input watts, and it’s calculated as a percentage. In power electronics, the Greek letter eta (η) is used to show efficiency.

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