One great thing about the California Solar Initiative (CSI) is that they keep pretty good data on the solar in their state. Thankfully it’s the US State with the most solar installations (4 times as much as 2nd place, NJ). So we can use CA’s data to find out which solar panel brand is the most popular.
The two most popular are SunPower and Sharp. Then, there’s a big drop off to Kyocera and Suntech. You won’t see BP’s number get any higher as the company has decided to shut down it’s solar division.
So, now that we know which solar panel brands are being installed the most, let’s see how difficult it can be to compare solar panels.
Solar panel efficiency is simple, but there a few things you need to understand.
There are 3 main types of solar efficiency.
1. Module Efficiency
2. Area Efficiency (Density)
3. Cell Efficiency
1. Module efficiency measures how well a solar module (aka panel) converts the Sun’s energy into usable energy. If the Sun dumps 100 Watts of energy onto the module and the module spits out 15 Watts, the the module is said to have 15% module efficiency (15 W / 100 W = 0.15 = 15%). If you want to brag to your friends that you have a top tier efficiency panel, care about this. Read the rest of this entry »
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).
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How much do solar panels decrease over time? The solar industry standard is a conservative estimate of 3% in the first year, and less than 1% per year after that. However, solar panel manufacturers are starting to realize that this is too conservative, and they are beginning to warranty their panels to more realistic degradation rates.
There are three points I want to make.
- Use the solar panel’s warranty to compare output loss over time because that is the only output you are guaranteed.
- Realistically expect less than a 3% decrease in output the first year, and about .5% decrease per year after that for most panels.
- One solar panel from 1979 was tested in 2010 (after 30 years) and its output was better than the original factory specs.
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Here are links to solar panel manufacturer warranty documents. Please contact us if you would like to contribute more! Thanks! Hope this is helpful.
Suntech - 2011 and 2010- JA Solar
- First Solar
- Yingli Solar
- Trina Solar
- Sharp
- Canadian Solar
- Sanyo Electric – HIT Series
- Sunpower Solar
- SolarWorld
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Brad had a very good question that I thought needed to be explained in a post of it’s own.
I’m confused as to how a less efficient system (measured under PTC) could output more.
The simple answer is – if there are more of the ‘less efficient’ panels.
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This is an infographic put out by 1Bog Solar explaining why solar works (well) in your state even if you think it doesn’t. Right click and choose “View Image” to view full size. Clicking on the image will take you to 1Bog Solar which is a group solar purchasing organizer. Think of them as the Groupon of Solar (before Groupon).
Yes, I recommend signing up with them, even if you don’t go solar with them.
Original link
Occasionally, people ask me how to choose the best solar pv system, or the best panels. Choosing the best solar system depends mainly on your energy needs, roof space, and budget. Most people really want to know how to choose the best solar value. For example, I was asked the following question on my “Help me help you” survey:
I got bid from 2 different installers. One was SunPower panels; the other Canadian Solar. The SunPower bid (for a 5.2 kw DC system) was $21,000 and the Canadian Solar bid was $14,000 – why so far apart?
Great question. There could be many explanations why there is such a gap in the price. Generally, SunPower’s superior efficiency allows for it/ necessitates that it price its solar panels higher. (They have to pay for the best engineers to get the best efficiency, right?) Each installer may be giving you the best deal he can with both brands of panels. What you should check on both proposals is not the DC system size (in this case 5.2 kw DC), but the kilowatt-hours output. Ask your installer(s) how much energy (in kwh) each system expects to produce in the first year. Read the rest of this entry »
SRoeCo Solar Answers Your Solar Questions!
- Which panels should I choose? – Solar Panel Comparison Article
1. a) What are the most efficient solar panels? – Solar Panel Comparison Table
- What size solar system do I need? – Calculate your solar array size
- How many panels do I need? – Calculate the number of solar panels
- How much will it cost to install? – Calculate the cost of going solar
- How much are the rebates? – Calculate California rebates
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Two great questions many people ask about solar panels are: “Which panels have the highest efficiency?” and, “Which solar PV panels are the best?”
This solar power panel comparison chart below compares the density and module efficiency (huh?) of the most popular 200 W solar panels. All of the modules on this chart are label rated at 200 Watts, which means in strict laboratory conditions, they produce the same output. However, I have compared them based on their PTC ratings which is the rating given under realistic test conditions. Sanyo, SunPower, Canadian Solar, Suntech, Trina, Kyocera, Schuco, BP, Yingli and Sharp are common solar panel manufacturers used by installers in the US.
(Updated 12.11.2011)
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The two most popular are SunPower and Sharp. Then, there’s a big drop off to Kyocera and Suntech. You won’t see BP’s number get any higher as the company has decided to shut down it’s solar division.
