In your research trying to understand solar power, you feel like solar panel efficiency is something you should be able to easily grasp. Efficiency should be easy to understand, right? Except the deeper you dig, the more confused you get. What’s the difference between solar cell efficiency and solar panel efficiency? Who can you trust when it comes to solar efficiency?
I got an email from someone purchasing solar panels from a supplier asking the difference between these two efficiencies. Helping people understand questions about solar is the whole point of this website, so after I answer a question via email – it often ends up here so that more people can learn.
Here’s the question:
My prospective supplier states that the Schuco 210 watt SMAU-1 panel has a cell efficiency of 16.8%, whereas your table gives a panel efficiency of 14.93%. What is the difference between panel and cell efficiency and which should be my guide?
There has been a shaking out period going on for a while in the solar industry. Big names like BP and Bosch have dropped their solar divisions, while other companies have just gone under like Konarka and of course, Solyndra (which never really was that big).
Well which manufacturers have not only held on, but are the most popular for solar installations in America’s largest solar market? We’re only looking at the last 2 years plus the first quarter of 2013. So that’s Jan 1, 2011 to Apr 17, 2013.
Want to know how to choose the best solar panels? It’s not too difficult: simply find out which ones give you the most electricity for the cheapest price. Let’s call this ‘solar value’. The lowest price per kwh can help you find the best solar panels.
Well, how do you figure out which panels give you the most electricity? Do I need to know which panels are the ‘most efficient’? Nope – actually you don’t. Efficiency is not the same as output. Efficiency is output per area. If you’re strictly looking for the solar panels with the best value, then you only need to care about the output. Let your installer worry about the area.
To simplify solar efficiency further, we have divided all modules into 5 tiers based on their efficiency compared to all other solar panels. Now installers and consumers can easily communicate about module efficiency. Are the solar panels in the most efficient tier (Tier 1) or do they have average efficiency (Tier 3)? If modules are in the least efficient tier (Tier 5), let’s hope they’re cheaper than the modules in the above-average tier (Tier 2).
Many people ask, “Which solar panel should I choose? Which panels are the best?” Though any salesman is going to tell you his panels are the best, the truth is that it is not easy to compare solar power panels and to firmly state that one brand stands out among the rest as the best.
The solar panel comparison chart I created below shows how difficult it can be to compare panels and brands. Listed are common panels between 190 and 230 watts of 5 common solar panel manufacturers (Canadian Solar, Kyocera, Sharp, SunPower, and Suntech).