When clients of Eco Green Energy trying to decide the most suitable solar panels for their system, they might find two types of efficiency indicators – one is module efficiency, and the other one is cell efficiency. Then, what is the difference between these two? Here we list several points for references.
How to calculate the module efficiency?
Let us take for example the Helios Plus 450W solar panel to calculate the module efficiency.
PV module power (Pmax in W) / Surface of PV module (in m) = 450W (Helios Plus) / 2.102*1.040m (Helios Plus) / 10 = 20.6%
(Source: Eco Green Energy Helios Plus 450W datasheet)
What is the cell efficiency?
The solar cell’s efficiency is the portion of energy that can be converted via photovoltaics into electricity by the solar cell. Also, take Helios Plus 450W for example.
(Source: Eco Green Energy Helios Plus 450W datasheet)
The most important point is that Eco Green Energy uses only grade A cells efficiency of 22.6-22.8%. And the reason is to make sure to have a positive tolerance on our Helios Plus PV module.
Why there is a difference between the two types of efficiency?
Cell efficiency is quite higher at 22.6 – 22.8% versus module efficiency at 20.6% as the above example of Helios Plus 450W. The reason for this difference is that cell efficiency is calculated as the energy hitting the individual cell, while module efficiency is the whole panel. Since solar panels often have spacing in between cells, some energy is losing.
(Source: google image)
Also, the bus bar on the panels is covering the cell surface as well. The thinner the bus bar is, the less efficient your module will lose. Moreover, the shadow of the bus bar on the cells. For example, the thickness of the BB of 5BB cells is 0.4 mm, against 0.1 mm for 9BB panels. This also led to a difference between module efficiency and cell efficiency.
In fact, the other raw material used to produce the panels, such as Glass, EVA, Junction box, etc… also has some influence.
Then, there is a “Fill Factor”, very commonly abbreviated as FF in solar energy technology is a measure of how closely a solar cell acts as an ideal source. This is a key parameter in evaluating performance. Also, it is simply determined the maximum power from a solar cell.
(The formula of FF for Helios Plus 450W solar module)
Last but not least, to get all of these details and more of Eco Green Energy solar PV modules, please do not hesitate to contact us: info@eco-greenenergy.com
