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Solar Panel Efficiency of Residential Solar System

Solar Panel Efficiency

What is solar panel efficiency?

A solar panel’s efficiency is generally determined by its ability to convert sunlight into usable energy. The Solar Panel area is the major decisive factor in deciding the panel efficiency rather than the power.

The prime consideration to calculate the panel efficiency should be given to the amount of sunlight that falls on the solar panel cells. . Solar panel shows cent percentage efficiency when the panel can convert the available total sunlight into usable energy. However, cent percentage efficiency is impossible in most cases.  Even, the latest solar panels are providing an average of 21% to 22% efficiency.

How it is measured?

A solar panel with an area of one square meter can produce 1kW of electricity at noon on the equator; then it can be called a 100% efficient panel. In other words, the panel would receive 1kW of sunlight and that gets turned into the same amount of electricity. If a panel with the same size produced 200W of power, then its efficiency can be calculated as 200W/1000W x 100 = 20%. It can be expressed in kW, then the equation becomes even simpler, as 0.2kW/1kW = 0.2.  The ratio can be multiplied by 100 to get the value in percentage.

solar panel efficiency

Why Efficiency is important rooftop solar systems?

Panel efficiency is a considerable factor to ensure the quality of the system and also in terms of return on Investment. In addition to that, you can effectively maximize the utility of the available roof space. The less efficient panel may cause an increase in the number of cells in your solar system.

If you have boundless space and are ground-mounting solar panels in a field or empty lot, efficiency matters less compared to the rooftop installation, where getting the most out of limited space is important.

How long does solar panel efficiency long last?

Solar panels’ degrading rate is a crucial factor that determines the ability of solar panels to turn solar power into usable electricity. The performance warranty offered by solar panel manufacturers shows the worst-case degradation rate over the life of the panel as expressed in its end-of-life efficiency. Degradation is inevitable for any kind of product. Solar also faces degradation, so efficiency will come down when aging. You can expect an average of 0.1% to 0.5% annual degradation for panels.

Where Solar Panels are tested?

There are various techniques to measure the panel’s efficiency. It can be measured at any of the accredited test centers under standard conditions.

List of Recognized Test Centers

  • European Solar Test Installation (ESTI)
  • Fraunhofer-Institute for Solar Energy Systems (FhG-ISE)
  • National Institute of Advanced Industrial Science and Technology (AIST)
  • National Renewable Energy Laboratory (NREL)
  • Physikalisch-TechnischeBundesanstalt (PTB)
  • Sandia National Laboratories (Sandia)

These centers are equipped to test hundreds of cells and modules each month. Along with that, they consult with hundreds of entities on PV measurements and solar simulation each year. Among these centers, NREL’s photovoltaic (PV) device performance services include high-precision performance testing, certification, and calibration of PV cells and modules, governed by rigorous global standards and decades of experience and expertise.

Top Brands Panel Efficiency

Company: Trina Solar
Model: Trina Vertex S+ Panels
Max efficiency: 21.9%
Specialty: Ultra-low Degradation, longer warranty, higher output
First-year degradation 1% and annual degradation at 0.4%
25 years product warranty and 30 years power warranty

Company: JA Solar
Model: JA Deep Blue Panels
20 to 21% to 21.3%
.55% Annual Degradation over 25 Years

Company: Jinko Solar
Jinko Tiger Ntype panels
Efficiency: 21.2 to 21.7%

Company: Longi Solar
Model: Longi Hi-Mo Panels
Efficiency: 20.9%

Company: Q Cells
Model: Q Cells Qboost solar panels
Efficiency: 21.4%

Company: Risen Solar
Risen Titan S Solar Panels
Efficiency: 21.6%

Company: Canadian Solar
Canadian HiKu6 Solar Panels
21.5%