What do we mean by "high efficiency" PV panels in the context of commercial roof tops ?
AFAIK thin film are around 10%, standard PVs around 20% and the multi junction are 30% but cost x10 for special uses only..
AFAIK thin film are around 10%, standard PVs around 20% and the multi junction are 30% but cost x10 for special uses only..
High efficiency = 5W STC rating per 156mm cell or better. More W per square meter. For example you can get cheap 72-cell panels that are rated at 320W, the best ones which are exactly the same dimension will be rated at 370, 375 or 380W. That is for typical modules which measure exactly 1.99 x 0.99 meters.
In large-scale solar, but not large enough to use a huge land area and low-cost thin films, there are two standard sizes of panels. 60-cell 1.65 x 0.99m and 72 cell 1.99 x 0.99 meter. These are standardized to work with a wide variety of different mounting systems.
There are many different grades and quality levels of polycrystalline and mono crystalline silicon solar panels.
The very best monocrystalline Si panels are made by Sunpower, but they have a significant price premium as compared to a pallet load that I could buy right now with my Visa card of qty 20, 370W panels. The commodity 370W are 65% of the price but only a few % less efficient.
"Standard PV" is probably what's available in bulk and cheap, is around 22-25%.
https://upload.wikimedia.org/wikipedia/commons/0/01/PVeff%28...
Special thin films cells in a lab may be 23%, what you can buy economically for a grid scale utility power plant is more like 14-15%.
This is at the very top end of the thin film market for what is now commercially available, and is 17%. See datasheet.