Solar panel efficiency refers to how well sunlight is converted by photovoltaics into electricity. This efficiency is influenced by various factors, including the type of photovoltaic cells used, the quality of materials and the technology employed in the panel’s construction.
Twenty years ago, solar panel efficiencies were between 10-15% depending on the technology (monocrystalline and polycrystalline) and manufacturer design. The National Research Energy Lab (NREL) maintains a visual chart that plots photovoltaic technology efficiencies as far back as 1976.
New PV panels have improved solar efficiency; the average efficiency of commercially available solar panels typically ranges between 15% and 20%. High-efficiency models, often using monocrystalline silicon cells, can reach efficiencies above 22%. Emerging technologies, such as multi-junction solar cells and perovskite solar cells, have achieved laboratory efficiencies exceeding 40%, but these are not yet widely available for commercial use.
Larger installation sites often evaluate the ROI energy efficiency benefits of a complete system replacement – switching out fully viable, working solar panels for a higher efficiency model. The result is a large volume of used solar panels for the secondary market.
Purchasing used solar panels is a trade-off between initial cost and reduced efficiency. Depending on the application, the lower cost per watt investment in a used solar panel offers high efficiency production creating an optimal ROI.
Sources
- “Solar Panel Efficiency – What Panels Are Most Efficient?” by EnergySage
- “Photovoltaics Report” by Fraunhofer ISE
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