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 12.43%. What is the difference between panel and cell efficiency and which should be my guide?
Great question.
Confusing chart of solar cell efficiencies
Cell efficiency is measured as the percentage output of energy to the theoretical amount of energy supplied by the Sun (hitting the cell). So if 100 Watts hits the cell (under Standard Testing Conditions, STC, which is laboratory conditions), and it spits out 16.8 Watts, then the cell efficiency is 16.8%.
My table gives panel efficiency of how much output of energy (as measured by PTC, which is the realistic test conditions of a panel on a roof) to the amount of space that panel takes up in squarefoot area.
Your supplier is right, but if you want a point of comparison, ask him to give you the “cell efficiency” of all the competitor’s panels. What my table allows you to do, is compare all the panels (eligible for rebates in CA, which is more than 1,700) by the panel efficiency. Though our efficiency measurements are slightly different, mine are standardized across all panels using the data that CSI (California Solar Initiative) uses to pay rebates. So, you can easily see how Schuco 210’s compare to any other 210 panels (or 200, or 220, etc…)
Hope that answers your question. He’s not lying. I’m just giving you more information.
Good news for solar, but bad news for future customers: the solar incentives for two of California’s biggest electric utilities have decreased by 40%.
The good news is that Pacific Gas and Electric (PG&E) and San Diego Gas and Electric (SDG&E) have received enough California Solar Initiative (CSI) applications to install solar that they have reached the maximum amount for Step 6 in the incentive scale. Current and future applications to install solar for customers of these two utilities will be eligible for the Step 7 incentive rate of $0.65/watt DC.
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 »
This is an excerpt of an article originally posted on AOL Real Estate written by Audrey Tempelsman. Audrey asked me to help her on an article you can read in full here.
There are a nerve-wracking number of solar manufacturers and installers out there, so I caught up with Shawn Roe of SRoeCo Solar, a solar advice service, and asked him to share five questions that all consumers should ask before purchasing a system. I hope you’ll find his insight as helpful as I did:
1. “How many systems has your company installed?”
Due to the recent spike in solar panel installations, and the decrease in other construction-related businesses, many roofers, fencers, and builders are attempting to start solar installation companies with no solar experience and without proper solar installation knowledge. Look for a reputable installer with at least 50 installations and a few references. Read the rest of this entry »
In a commitment to advancing the solar renewable energy movement, SRoeCo Solar created the “Solar Electric Cost Commercial” to promote the benefits of solar electric systems through creative marketing and advertising.
Calculations behind the “Solar Electric Cost Commercial” after the break.
Highlights from the Intersolar 2009 North America solar show in San Francisco, California that was held July 14-16 at the Moscone Center.
Michael Kanellos, Editor in Chief of Greentech Media, gives a short tour of the conference asking the question, “what’s the solar panel of the future - silicon or thin film?” View the video after the break… Read the rest of this entry »
Many people are under the false impression that you have to be an environmentalist to have interest in installing solar. Paying the upfront cost to install a solar electric system is something only a “green” person would do. Well, that’s not true anymore. Here are 5 financial reasons to go solar now!
1. Utility rebates are decreasing as more people decide to install solar.
The California Solar Initiative (CSI) program will provide more than $3 billion in incentives for solar-energy projects in California. However, the amount of the incentive is scheduled to decrease in 10 steps over the duration of the program. Pacific Gas and Electric (PG&E) and San Diego Gas & Electric (SDG&E) are already in step 5 for residential projects, while Southern California Edison (SCE) recently dropped into step 4.
The difference between step 4 and 5 for an average size, 4 kW, solar electric system, is approximately $1,000 in your pocket. The longer you wait, the more rebate money you lose! Read the rest of this entry »
In a commitment to advance the solar renewable energy movement, SRoeCo Solar created the “Solar Car Commercial” to promote the benefits of solar electric systems through creative marketing and advertising.
