A solar panel datasheet contains the main specifications and key features of a photovoltaic module.
This is the data you need to integrate solar modules into a solar power system.
‘Nominal power’ is what is stated as power in Wp (watts-peak) in the solar panel datasheet. Therefore, ‘nominal power’ is what you get as the power output from a photovoltaic panel. Nominal power is important for solar panel system sizing and evaluation. As ambient temperature increases, solar panel efficiency (the ability of a solar panel to convert solar energy into electricity) gradually decreases. Therefore, at a certain high temperature, the generated solar electricity reaches its lowest value.
Furthermore, as temperature decreases, efficiency increases. This means that if you have bought a solar panel of 200Wp nominal power, it might generate 20–30% less electricity in summer than in winter. For various panels, such a temperature dependence of the solar generated electricity will vary.
It might surprisingly turn out that in your climate, a more expensive solar panel will produce much more electricity annually than a less expensive one, provided that both panels are of the same nominal power. Thus, a more expensive panel could definitely turn out to be more beneficial from a financial point of view.
Cost per watt, or $/W, is a commonly adopted way to compare costs of generating electricity. For photovoltaics this refers to the solar generated electricity and is calculated by dividing the total investment costs of a solar project by the total power of the solar panels installed, also known as ‘peak power’ (watts-peak or ‘Wp’).
A solar panel of 220 Wp nominal power, bought for $270, will have a cost-perwatt value estimated as follows: $270 ÷ 220 Wp = 1.23 $/Wp
Why the universal measure ‘cost per watt’ could mislead you?
You are faced with the option of either buying a 220Wp solar panel for $270 or buying a 180Wp panel for $221, and you are wondering which option is better. From the Cost per Watt universal measure point of view, both panels are equal since for both options the Cost per Watt is estimated as equal to $1.23.
It could turn out that, considering the seasonal changes in temperature, the lower rated output panel of 180Wp will generate more energy on an average annual basis than the higher rated power panel of 220Wp.
— — — —
Furthermore, from the required installation area point of view, it could turn out that a solar panel of a lower output could be more advantageous for you since it could require a smaller area to install. Be sure that if you use the nominal power data provided by the manufacturer, without even considering the better efficiency of the lower rated panel under the environmental influence, you could easily end up in a situation when you need to install a greater number of panels.
Don’t forget that a solar panel system’s lifecycle is at least 20–25 years! If you do not perform such an evaluation, or let yourself be misled by a solar vendor or installer, the money lost as a result of underperforming solar panels or solar panel system, could amount to a couple of thousand dollars across the system’s operational period!
The most important solar panel rating or how NОТ to lose money as a consequence of misinterpretation
The lines below are quite significant, as they could save you a lot of money. Here we are going to help you choose the best solar panel in terms of money and guaranteed performance over the years, by understanding key performance ratings of solar panels.
Thanks to this info, you will be able to find the “right” solar panels for your solar endeavor. Furthermore, you will be able to look for important words and parameters in solar panel datasheets that solar manufacturers use to “conceal” inferior solar panels.
By the end of this blog post , you are going to find how the lack of just one word in a solar panel guarantee statement might cost you a lot of money in the long run.
Also, don’t forget that the right choice of solar panels is 80% responsible for the overall performance of your solar power system. Get it wrong and you’ll lose a lot of money in years to come! This article might seem boring at first glance. But we believe that the eventual financial reward is worth your patience!