Effectiveness of a Solar Panel

By Milton Kazmeyer
Digital Vision./Digital Vision/Getty Images

In the quest for renewable, clean energy, solar has become one of the dominant technologies due to its low impact on the environment and ease of use. While almost anyone can take advantage of solar energy in some form, not all solar installations are equal. Many factors can alter the effectiveness of a solar panel, and these can make a significant difference in the total power generated and the length of time before the energy savings cover the cost of the hardware.

Solar Intensity

One of the biggest factors that affects the output of a solar panel is solar intensity. Not every spot on Earth receives the same amount of energy from the sun each day, due to the tilt of the Earth and local climate conditions. The closer you are to the equator, the more direct sunlight you receive, and drier climates have fewer clouds to interrupt power generation. Ultimately, this means a solar panel installed in the Mojave Desert could generate almost twice as much energy as one installed in New England or the Pacific Northwest.


While a solar panel will generate current anytime sufficient sunlight strikes the photovoltaic medium, peak generation requires direct sunlight. To maximize collection, some panels use a tracking system to tilt the surface in order to follow the sun across the sky. Single-axis trackers tilt the panel from east to west, while dual-axis systems can also alter the north-south tilt to compensate for seasonal differences in the sun’s angle. These systems can add to the cost of your solar installation but can increase your solar power output by 20 percent to 50 percent depending on the season and your latitude.

Photovoltaic Efficiency

Another factor in solar panel output is its efficiency. Each solar panel has an efficiency rating, measuring how much of the sun’s energy it can convert. As of 2013, most panels on the market convert somewhere between 20 percent and 25 percent of the energy received into electricity. While technological developments constantly push this figure higher, solar generation currently faces a hard limit of around 33 percent efficiency with current technology. A few percentage points’ difference in efficiency may not seem like much, but over the decades of service a panel offers, it may add up to a significant difference in total output and total energy savings.


Proper maintenance can also increase the effectiveness of a solar collector. Exposed to the elements, the flat glass surface of a solar panel attracts dust, dirt, residue from precipitation and other contaminants that can effectively reduce the amount of sunlight that reaches the solar cells. Inspection and cleaning at least a few times a year will prevent buildup and loss of effectiveness.

About the Author

Milton Kazmeyer has worked in the insurance, financial and manufacturing fields and also served as a federal contractor. He began his writing career in 2007 and now works full-time as a writer and transcriptionist. His primary fields of expertise include computers, astronomy, alternative energy sources and the environment.