Most Efficient Solar Panels
| Published in Efficiency, Learn | 48 Comments
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)
Of the highest output panels, both Sanyo and SunPower panels have the highest efficiency per surface area in real world conditions. Given a limited roof area with which to install solar panels, these panels are the best choice to produce the most electric output per square foot. However, this doesn’t mean that these panels will always be the best choice. Well, how should you choose solar panels then? Here are 5 questions to ask your installer before going solar.
The chart below shows some of the most common and efficient solar power panels on the market and listed on the State of California’s “List of Eligible SB1 Guidelines Compliant Photovoltaic Modules” as of Dec 11, 2011.
I’ve even included Solyndra’s 220W module, which you can see has the worst efficiency per area of all the panels because it’s not crystalline, but thin-film. Yes, thin-film is significantly less efficient than crystalline (mono and poly) panels.
So, if I know the most efficient solar panels, then I know which solar panels are the best, right? Well, if efficiency is all you care about, then yes. But efficiency may not be the most important factor. I would argue that the two most important factors in choosing the best solar panels are 1) the annual kWh production (the expected output) and 2) the price.
Would you pay more for “more efficient” panels, if I told you I could get you a less expensive system that outputs more, fits on your property and lasts just as long? Wait, less efficient panels can produce more?!
Okay, these are the common ones. But which are the most efficient solar panels of them all?
Chart Key:
Manufacturer = Solar Company; Brand
ID = Specific solar module identification code; module name
STC (W) = Standard Testing Conditions Rating; nameplate rating under laboratory conditions
Density (W) = Efficiency per area; realistic output per area, the higher the more output in a given area
Efficiency (%) = Output per input light irradiance using STC; energy conversion efficiency; module efficiency
Tier = Solar Panel Efficiency Tier. 1 is highest, 5 is lowest
November 7th, 2009 at 6:54 pm (#)
Ok…so im confused. Is a 200W Sanyo Panel the equivalent of say a 240 Evergreen based on its efficiency? If I install a 5KW system with 200W Sanyos or 240 Watt Evergreens – which system would produce more during the course of the year?
thx great website. Add more for us dummy laymen types!
December 22nd, 2009 at 7:45 pm (#)
Great questions Gordo. Generally, the PTC rating of the module (solar panel) is the best way to compare which panel will produce more during the course of the year. The PTC rating is a more realistic rating of the panels tested under real-world conditions as opposed to laboratory conditions.
Each 5 kW system will produce slightly different depending on many things (tilt, direction, shade, etc). The easiest way to compare systems is to have different solar companies give you free evaluations (proposals) on a system. After they explain everything, ask them what the “expected first-year output in kWh’s” is, and then you can see which system will produce more during the course of a year.
What kind of information can I add to help the dummy laymen types? I’m open to suggestions. My goal is to simplify solar as much as possible. Thanks for the comment!
January 25th, 2010 at 12:18 pm (#)
I’ve been talking to a local solar company, but I don’t feel I have quite enough information to take the solar leap. Some questions:
I’m looking at three systems; a Sunpower 235wt (24 panels), a Sunpower 210wt sytem (24 panels), and a Sharp 235wt sytem (22 panels). These are arranged in most-to-least expensive. Net costs after rebates, taxes,etc. range from about $24,000.00 to $22,000.00 to $19,000.00
One thing none of your charts considers is aesthetics. The all-black Sunpower panels are a lot better looking than the Sharps, and in this situation quite important. So, am I foolish looking at the more expensive systems, or does anyone else make a good-looking product?
How much wiggle room is there in these quotes? This cliff is pretty steep. I don’t know if I should jump now or wait until other companies come up with less industrial-looking systems.
Thanks for your imput Rick
January 25th, 2010 at 4:52 pm (#)
Glad to hear that you’re talking with a local installer. You’re correct: my charts do not include aesthetics. Beauty is in the eye of the beholder, no? It would be hard to scientifically measure aesthetics. However, you’re not the only person who has considered the looks of the system. Looks actually ends up being an important factor for many people. Your major differences in price of these three systems are going to come from their output, not their looks.
Sharp actually recently came out with the OnEnergy roof-mounted system with a “low-profile rack designed to blend beautifully with a home’s roofline”. Ask your installer if he can provide this system.
The cliff’s not as steep as you think. Solar panels are going to look like solar panels. Companies are focusing on improving efficiency and reducing cost much more so than they are working on aesthetics. Don’t wait for that reason. Plus, the sooner you take the plunge, the sooner you’ll reap the benefits!
As for wiggle-room, solar installers actually have low profit margins despite the news that it’s a booming business. The competition is strong (which is good for the consumer). The wiggle-room, if any, will be in the salesman’s commission. Talk to multiple installers, but remember – they’ve got to feed themselves too.
Good luck Rick!
February 4th, 2010 at 4:28 pm (#)
I’m looking for the highest wattage per square foot, but the price on the 20% efficient sanyos are $4 per watt.. Is there anything more efficient than these yet as your post is getting old… The more wattage per square foot the better.I am going to cover a car with them as much as I can to run a hydrogen generator, and I will need as much power as i can possibly fit into that space.
February 4th, 2010 at 6:01 pm (#)
My charts are currently up-to-date. (This table is always up to date). There is nothing available on the market more efficient that what is listed. Anything more efficient has only been achieved in research laboratories and has yet to be available for the common consumer.
I will be sure to update these charts when new efficiencies are reached. However, don’t expect this to happen regularly. Solar cells are not equivalent to computer chips. Let us know how the car progresses!
February 18th, 2010 at 4:24 pm (#)
Where does this data come from?
Is it from the manufacturers, from a testing lab, or from real-world conditions?
If it is from real-world conditions, which part of the real world? Was the testing done in New Mexico or Maine, or somewhere in between? And if so, does it cover a full year cycle? Were all of the panels tested at the same location?
I know some panels behave better in low light conditions, some are more shade tolerant, heat tolerant etc. I would like to see some true side-by-side annual (or multi-year) results, especially if they come from the northeastern USA.
March 3rd, 2010 at 10:24 pm (#)
This data comes from the List of Eligible SB1 Guidelines Compliant Photovoltaic Modules used to receive California state rebates related to solar installations. It is from PV USA Testing conditions performed at a research facility in Davis, California. California is by far the state with the most solar installations at more than 530 megawatts (MW). New Jersey and Colorado are a distant 2nd and 3rd with 70.2 MW, and 35.7 MW installed respectively (according this Reuters report). This is why the current data is from California, and not the Northeastern USA.
The data is mainly for comparison purposes as the measurements are consistent. Local installers will have more information regarding local production output. My comparison charts are best used to confirm and/or ask about differences in output or efficiency.
–from List of Eligible SB1 Guidelines Compliant Photovoltaic Modules
March 5th, 2010 at 11:18 am (#)
I am confused. I live in So.Cal. and am getting estimates from 3 companies, the first, Solar City is going with the Kyocera panels (preliminarily), but I don’t see Kyocera listed on the California SB1 Compliant list. I also see that SunPower’s panels are more efficient. Since we are considering a PPA or lease, does it matter?
March 7th, 2010 at 1:22 am (#)
Hello
Nice chart! Very usefull.
Can I ask you why SunPower 300 and 315 are not included?
March 7th, 2010 at 10:35 pm (#)
Hello Matej,
Thank you. SunPower 300 and 315 are not included on the chart above because the chart is of “30 of the most common” solar panels used. The size and cost of the SunPower 300 and 315, though they are very efficient, cause them to be used in solar installation projects much less commonly than the panels listed. That’s why I have included a link to the 40 Most Efficient Panels available which includes both mentioned. Good question!
March 7th, 2010 at 10:49 pm (#)
Hi Jocelyn,
It doesn’t matter. A solar leasing or PPA (power purchase agreement) installer like Solar City can use whatever panels they want, because they will own the system, which means they receive the rebate (not you). Several Kyocera panels are listed on the CA SB1 Compliant List, and if you were buying a solar system from an installer in California, you should make sure that your equipment makes you eligible for the rebates. But since it’s a PPA, it doesn’t matter for you.
PPA’s or solar leasing are great ways to go solar, and as long as you feel you understand the terms and are getting a good deal (which you likely are) then you don’t need to worry about eligible or efficient equipment. You only buy the energy produced, and the provider will make sure that it installs solar panels that produce over the long-term, or they won’t make any money! So you don’t have to worry!
Thanks for the question! Glad you’re going solar! You’re going to be happy that you did!
March 18th, 2010 at 3:33 am (#)
[...] become more efficient, rising from less than 10 percent conversion rate a decade ago to more than 15 percent today (in real-world trials) for affordable panels, the possibility of solar systems becoming affordable [...]
January 9th, 2011 at 9:43 am (#)
[...] Solar Panel Efficiency Chart Green [...]
August 24th, 2011 at 10:36 pm (#)
What does anyone know about Topsun solar panels ?? Are they reliabale ?? They have been offered by a local company in Oz but I can’t seem to find out anything on them from other suppliers. They talk about a cell efficiency of about 18% for cells in their 400W panels.
September 8th, 2011 at 8:47 pm (#)
Where are panels from First Solar? They have proven efficiencies of over 17% and low cost. Are they not available to residential customers?
September 9th, 2011 at 6:29 am (#)
Brad,
Good questions. The charts above show panels of 200 W ratings, and common panels used in the 200 W rating range. First Solar produces thin-film solar panels with the highest panel rating of 87.5 Watts, which is why you don’t see them in the charts above.
Because First Solar uses thin-film technology, their efficiencies are relatively low compared to standard pv modules. You’re right though, their cost is low as well. The 17% efficiency that you reference was only achieved in July 2011 in a lab. Unfortunately, First Solar currently does not offer modules of this efficiency on the market yet.
First Solar modules are available for residential installations, though they tend to be used much more widely on installations of 10 MW and higher (which are usually commercial installations).
You can compare First Solar efficiencies on the solar comparison table. Simply type ‘First Solar’ in the Search bar.
Yours in solar,
SRoeCo Solar
September 13th, 2011 at 12:19 pm (#)
I am in AZ (Cottonwood) and am considering a lease with either Sungevity or Solar City. Are they both o.k. companies
September 13th, 2011 at 4:24 pm (#)
Hello Kenny,
Yes, Sungevity and SolarCity are two of the largest solar companies specializing in solar leasing. They are both o.k. companies.
Yours in solar,
SRoeCo Solar
September 14th, 2011 at 4:41 pm (#)
I did not see a rating for the BP3230T model or the Mitsubishi PV-MLU255HC. Have you rated them?
September 14th, 2011 at 4:56 pm (#)
Hello Susan,
Yes, you can find the compared efficiency ratings of both of these specific modules on the Solar Panel Comparison Table. Simply search for any module in the search bar.
I hope you find this useful!
September 17th, 2011 at 6:18 pm (#)
Hmm…
Thanks for the article, but I’m a bit confused…
For example, you wrote:
“But efficiency may not be the most important factor. I would argue that the two most important factors in choosing the best solar panels are 1) the annual kWh production (the expected output) and 2) the price.”
and
“PTC= PVUSA Testing Conditions (realistic test conditions)”
So, if I understand the above correctly, assuming the realistic test conditions are, in fact realistic, doesn’t that mean that the most efficient panels (measured under PTC conditions) will produce the highest annual kWh production (have the highest expected output)?
You also wrote:
“Would you pay more for “more efficient” panels, if I told you I could get you a less expensive system that outputs more, fits on your property and lasts just as long?”
While of course, I’d opt for the less expensive system that outputs more (yet is somehow *less* efficient??) I’m confused as to how a less efficient system (measured under PTC) could output more…
Thanks for any insight you can offer; I’m fairly new to all this.
-Brad
September 21st, 2011 at 12:53 am (#)
Hey Brad,
Your question was so good, I decided to answer it in a new post titled “Less Efficient Solar Panels Produce More?“. Thanks for the question. Hope I’ve answered it sufficiently.
September 29th, 2011 at 10:35 am (#)
Thank you for the article. I recently attended a seminar for Solagex and was impressed. Thay use Canadian Solar-CSP-230P panels and A SMA America-SB5000US(240v) Inverter. Ithink I understand about the panels but you havent discussed what part (if any) the inverter plays in the efficiency of the system. And can you please also include a response as to the repudability of Solagex. Thank you
September 30th, 2011 at 11:08 pm (#)
Hello Martini,
You’re right, inverters play a role in the overall efficiency of a solar pv system. I’ll work on an article and maybe even a comparison for you soon. As for Solagex, I’m sorry, but I know less about them than you, so I can’t comment on their reputability. If you’d like me to look over any quotes you’ve received, I’d be more than happy. You can use the contact us page.
I also highly recommend to everyone to get multiple price quotes from different installation companies. Comparison shopping is good for everyone.
October 13th, 2011 at 2:16 pm (#)
Hi,
Thank you for the good article.
I leave in west Africa where the temperature is very high and the sun very bright. I would appreciate if you can recommend panels that have high efficiency at high temperatures and are rugged.
Thank you,
Rudman
October 13th, 2011 at 11:32 pm (#)
Hello Rudman,
No problem. All solar crystalline pv modules are rugged enough to withstand extreme weather conditions. You can find highly efficient panels at higher temperatures by looking at panels with ‘Power Temp Coefficients’ closer to zero (0).
1. Go to the comparison table.
2. Click on the ‘Power Temp Coef.’ link. This will display that column in the table.
3. Now click on that column title in the table. This will sort the column, putting the panels with the best ‘temperature efficiency’ at the top.
4. Lastly, in the Search bar in the table type a number like ’200′, or ’210′, or ’220′. These are common panel ratings of solar panels.
Now you can easily see which panels have high efficiency at high temperatures!
October 16th, 2011 at 10:01 am (#)
thanks for the info. i recently attended a talk by a local installer that offers two brands of modules as options. i can’t remember the lower cost/less efficient per size brand, but he claimed that the more expensive, smaller, more efficient panels manufactured by schott (a german company that manufactures the panels in new mexico) were 20% efficient. schott has lots of specs on their website, but i don’t know what all the tech talk means and i don’t see the “20% efficient” claim there. do you know anything about these being 20% efficient? from what i can read of the independent testing they seem to be of very high quality. thanks!
October 17th, 2011 at 5:11 pm (#)
Hello George,
You’re right, the installer was exaggerating the efficiency, or made the mistake of simplifying the numbers instead of simplifying his explanation. Glad you’ve done the independent research on your own. Schott does make high quality panels. Don’t worry too much about efficiency. The best thing to do is to ask for a free solar estimate for your specific situation (ie. location, building, electricity usage) from 2 or 3 different solar installers. THEN, compare the specifics of their offers. Feel free to contact me after you’ve received the quotes if you’d like help comparing offers. Glad you’re considering going solar!
October 21st, 2011 at 3:02 pm (#)
Sanyo has 21% efficient panels in Europe, they recently were approved for the U.K. too.
And for the DIY guys and gals, there are several 17% efficient solar cells (I didn’t check for panels) on the Chinese portal alibaba.com, for about $1/W.
November 1st, 2011 at 7:29 pm (#)
hi,
how can solar cells loss power to module.
for example cells have 16.7% efficiency then after install to module it will be around 16%
it that due to EVA or glass.
please explain detail to me.
sorry for my bad english
November 2nd, 2011 at 10:43 pm (#)
Hi have you done a comparison on AC solar panels with Microinverter vs Solar panels with a traditional inverter, and how do the System stack against each other. I am trying to go solar but i don’t which system to choose. I don’t want to invest on a traditional system with one inverter, if the solar market is moving to AC solar panels and microinverters.
November 3rd, 2011 at 10:43 am (#)
This is a very helpful website! Keep up the great work! I am a college student considering fitting my parents home with solar panels and have been doing some research on them. Hopefully I can convince them to do so if I get some quality hypothetical results.
November 5th, 2011 at 11:36 pm (#)
John – The manufacturing of solar cells is a highly intricate process that results in solar cells produced with varying efficiencies despite coming through the same processing facility. The efficiency of a panel (or solar module) is a collection of many of these individual cells wired together. The wiring, connection, and combination of the cells will result in a model efficiency being less than the laboratory-produced efficiency of single cells.
November 5th, 2011 at 11:40 pm (#)
Fernando – No, we don’t yet have data comparing microinverter output vs standard inverter output. The usage of microinverters on solar panels is still relatively new, so we don’t have any reliable comparison data. Microinverters can generally be expected to produce slightly more output compared to standard (big box) inverters, but if they produce enough to make up for the extra cost depends on individual scenarios. Ask your installer(s) to give you a price estimate for both options and then you can compare the cost and expected output differences. Feel free to contact me if you’d like help comparing installer estimates.
November 10th, 2011 at 8:10 am (#)
Hello,
Thanks for the useful information. I am currently researching if there any solar panels fitted with tracking system to detect the most sunshine available and position the solar panel accordingly to get the best energy output scenario? Is it efficient to use that system?
November 15th, 2011 at 2:47 am (#)
which is best QUASAR 260 SERIES or PLM_M_ SERIES panels
November 15th, 2011 at 5:58 am (#)
Hi SRoeCo Solar
Firstly, many thanks for sharing great source of information and conducting very absorbing discussions from both you and readers. Fantastic job indeed!
I am about to start business, providing telecom and computing solutions for government and corporate sectors completely based on standalone UPS power from Solar Photovoltaic panels. I want to use DC power supply only in these systems where possible. Grateful, if you can advise on what is the best way to start accurately calculating Solar Panel and Battery needs (including over space and weight needs as this is going to be mobile solution). I have browse through many sites but none provides complete picture.
Warm Regards / Arvind
November 22nd, 2011 at 6:06 am (#)
Pavel,
Solar tracking systems are calculated to track the Sun based on it’s position in the sky during specific times of the day and days of the year. They are automatically designed to maximize output in that regard. Yes, you will gain efficiency using this type of system as long as the output difference is greater than the energy needed to move the panels. Trackers also add cost ($) to the overall system.
November 22nd, 2011 at 6:07 am (#)
William,
You can compare more panels using my Solar Comparison Table.
November 22nd, 2011 at 6:22 am (#)
Arvind,
Glad you appreciate the site. It’s my pleasure. Designing a battery DC solar system from scratch is no simple task. I’m sorry that I can’t advise you in this area. Two resources to check are Backwoods Home and SolarPro Magazine. You’ve got an interesting idea! If you hope to succeed, don’t give up. The world needs more sustainable energy entrepreneurs.
November 23rd, 2011 at 4:27 pm (#)
[...] panels in ready supply throughout California are rated at 15.64 percent efficiency, according to SROeCo. Solar panel efficiency is calculated by dividing the power output in watts by the surface area of [...]
December 1st, 2011 at 1:08 pm (#)
Hi,
I have just had a 4.5kW system installed by a professional company in Australia. The system uses 20-Suntech 225W panels and a 4.2kW Aurora Inverter.
We have not seen a Peak Power reading greater than 3.1 kW on the inverter meter since installation one month ago. This is despite perfect conditions with with clear skies and the sun directly overhead. Ambient temperature was noted to be low, 20-25 degrees when the observations were made at mid-day. The panels are inclined at 30 degrees and face directly north (optimum orientation conditions). Our lattitude is approximately 37 degrees south and there is no shading on the panels.
My instincts tell me that there is a problem with the system due to the low peak power readings seen. Given that power generation conditions are excellent, what percentage of the advertised 4.5kW should I be seeing at the inverter meter.
Suntech guarantee their panels to have 95% of rated output in the initial years of their life. Is the lower rated 4.2kW inverter the problem? For your information, I have compared readings on the same days with a neighbour who has a ten year old system. He reports 85% power generation of his system’s rating
Your advice is appreciated.
Paul.
December 2nd, 2011 at 12:15 am (#)
Hello Paul,
I believe your instincts are correct. There seems to be a problem with the system. You should contact your installer, inform them exactly what you’ve written here: mainly that the peak ratings have not been higher than 3.1 kW for the first month. This is about 69% of the 4.5 kW rating, when you should be maxing a lot closer to 95% peak power readings (or ~4.2 kW).
You can check other solar pv output data at http://www.pvoutput.org. Here is an example 4.464 kW system with Suntech panels for your comparison.
Thank you for describing your situation so well. Please, let us know the solution to your issue when it is found. Though most pv systems should work without a hitch from the start, your situation could be helpful to future pv system owners.
Yours in solar,
Shawn
December 14th, 2011 at 10:30 am (#)
Hi All,
Its interesting to compare module efficiency, but in most cases, it’s little more than an academic exercise, as long as you are comparing the PTC or CEC ratings, and not relying on the STC ratings that look more favorable.
There are only 2 conditions where the module efficiency matters for residential installations:
1. Limited mounting area requires a more expensive, higher efficiency module to allow the desired array to “fit” into the available space. In other words, you need a 5 kW array, and only 4.6 kW would fit with the lower efficiency modules, so you decide to purchase the more expensive option to reach the 5 kW goal.
2. If there is a big difference between the STC and the PTC, you should figure out expected production, and compare price quotes based on that. Solar modules and even installed systems are sold by the Watt, just as chicken is sold by the pound (or kg). Usually the STC is the figure used to price a system at, say, $5.50/watt. Comparing the cost to the more realistic PTC or CEC numbers would give a better representation of which offer was the best value.
There is no sense in a potential solar customer waiting until the efficiency reaches some particular level — a 4 kW system will make the same amount of power at 35% efficiency as at 15% — it just takes up less room to do the same work.
Clear skies,
Brad Vietje
Green Works Solar Store
Groton & St. Johnsbury, VT
January 29th, 2012 at 7:27 am (#)
Hey Guys, I keep hearing about efficiency going up, but I don’t seem to ever see it happening. I fully expect the multijunction cells to get here eventually, but I also expect them to be expensive. I keep expecting the real specs like $/watt and $/area to go down, and even if the cells are more expensive the assembly process costs must still be a large chunk of the price. Given that the global installed volume is ‘charging’
up fast, I would expect the installed price/watt to keep coming down. When is all of this going to become practical, after the subsidies end?
February 2nd, 2012 at 1:45 pm (#)
this is wealth of information! thank you,
I have some questions about the longevity of solar systems. it appears that most systems are guaranteed for about 20 – 25 years. but what happens after that? would you have to purchase a whole new system?
what type of maintenance is necessary to maintain the system?
February 2nd, 2012 at 8:46 pm (#)
Thanks Joey. Actually, nothing happens. The panels keep producing energy even after 25 years. It’s possible that the panels could continue producing energy after 50 years (albeit likely at 60-80% of what it produced in Year 1). So, no, you won’t have to purchase a whole new system. You would likely have to replace the inverter every 10-15 years, but not the panels.
Maintenance is typically keeping the panels clear of too much debris (dust, dirt, leaves, etc). Depending on where you live, simply hosing the panels down with water every few months is sufficient. Here’s an article on 1BOG about solar monitoring and maintenance.