Everything You Need To Know About Solar Panel Efficiency!

Solar technology has grown by leaps and bounds in recent years, with greater solar cell efficiency, higher power output, and overall superior quality. The first thing buyers looking for the most efficient solar energy system should know is how to compare efficiency numbers from various manufacturer brands. The solar panel efficiency is a good metric for measuring how much power a solar panel generates compared to similar things.

Solar panel efficiency is a measurement of its ability to convert sunlight into useable electricity. For example, if the sun shines on a high-efficiency solar panel with a 20% rating, 20% of the sun's energy is converted to solar power. When the same quantity of sunlight shines on two solar panels with different efficiency ratings for the same amount of time, the more efficient panel will produce more energypower than the less efficient panel. The production of energy by solar cells determines solar panel efficiency, which is impacted by the cells' composition, electrical setup, surrounding components, and other factors.

Nowadays, most solar panels are between 15% and 20% efficient, with outliers on either end of the spectrum. High-efficiency solar panels can exceed 22 percent efficiency in some situations. However, most photovoltaic panels on the market are less than 20 percent efficient. Higher efficiency panels are slightly more expensive, but they will help you fulfill your energy needs, especially if you have a smaller roof with limited space.

It is critical to note that the efficiency of a single solar cell does not equal the efficiency of a solar panel (module) as a whole. While solar panel efficiency is typically about 15-20%,  solar cell efficiency can exceed 42 percent in certain situations.

However, solar cell efficiency is measured in the laboratory unless otherwise specified. As a result, while 42 percent is a fantastic performance, laboratory conditions differ from real-world situations, which does not apply to homeowners.

How To Calculate Solar Panel Efficiency

  1. Multiply the length by the width to get the panel's surface area. The surface area is the open area of the solar panel. Therefore it includes the frame.
  2. Take the panel's nameplate rating from the datasheet. For example, if the panel is 235 W, the nameplate rating at STC is 235 W. (Standard Test Conditions)
  3. The watts per meter squared (W/m2) at STC is 1,000 W/m2. This is the unit of measurement used to quantify how many watts of power are produced in a square meter of the earth's surface. (Note: Because temperature is always a role in panel output, STC assumes less than 77°F.)
  4. To get the solar panel efficiency, divide the nameplate rating by the square meters at 1000 W/m2.
  5. Remember to check the power tolerance since the nameplate rating may be 245W. The power tolerance will tell you how many more or less Watts the panel produces based on the STC. 


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