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Clean Power Best_Research-Cell_Efficiencies

Published on February 2nd, 2014 | by Zachary Shahan

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Which Solar Panels Are Most Efficient?

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February 2nd, 2014 by Zachary Shahan 

Originally published on Cost Of Solar.

One of the most common things people ask when they start to consider going solar or start to plan their life-changing solar expedition is which are the most efficient solar panels. However, first of all, that’s not even the right question for most people, and second of all, the literal answer to that question really isn’t relevant for the average consumer. Let me explain….

First of all, the important matter is not which solar panels are most efficient, but which solar panels are the best value for the money. If you’ve got space for 10 solar panels on your roof and you have an option between solar panels “ABEfficient” that are a bit more efficient but twice the price of solar panels “CDCheap,” chances are, you are going to make a much bigger savings by going with CDCheap. Of course, the important thing would be to see what’s available in your situation and simply run the numbers (or, if you are allergic to math, have a friend who can do math run the numbers for you).

But, anyway, if you really want to know which are the most efficient solar panels (or solar cells) out there, I actually happened to be putting together a list of solar records recently and can give you the rundown. But, as I do so, I’ll drop in a few key notes making the point above a bit clearer. Before looking at solar panels as a whole, let’s have a quick look at the producers of some of the most efficient solar cells (the key component of solar panels) and their efficiency records:

  • 44.7% efficient solar cells by Fraunhofer. Notably, these world-leading solar cells from Fraunhofer are in the concentrator triple-junction solar cell category. Such solar cells are complicated and are not used in residential or commercial applications… because they are bloody expensive. They are used in space applications by the likes of NASA, where a bit of extra space (or, as it may be, less space via extra efficiency) can make a huge difference.
  • 37.9% efficient solar cells by Sharp. Just a step down, these are in the triple-junction, non-concentrator solar cell category. If this is all new to you, it might take you awhile to see the difference in the categories. The difference is that these solar cells don’t use anything to concentrate the light hitting the solar cells, while the 44.7% efficiency cells above do use something to concentrate the light (of course, adding to their costs).
  • 32.6% solar cells by a Spanish solar research institute (IES) and university (UPM). These are another step down, as they are in the two-junction, concentrator solar cell category. (For an intro on “junctions,” by the way, check out this multi-junction photovoltaic cell article on Wikipedia.) Again, these are still far different solar cells from what are used in commercial or residential installations.
  • There are about a dozen or so extra categories that I could run down. Some categories have very high efficiencies but the solar cells are quite expensive, while others are actually on the other end of the spectrum (no pun intended) and are very cheap but have very low efficiency. Of course, some are both inefficient and expensive, but apparently worth researching nonetheless. The key, as I noted earlier, is finding the best balance between cost and efficiency.

Now, there’s less research on solar panels than on solar cells because the core of the technology is the solar cell, so that’s what researchers at many institutes and universities spend their time on. No one is even going to try to manufacture a solar panel that won’t sell because it isn’t made of marketable solar cells. Still, there are many different types of solar panels (more accurately known as solar modules) on the market and many, many manufacturers of some of the most common types. So let’s look at the leaders in this category.

Why didn’t I start with the solar modules? Because then it would be easier to miss the point, which is that solar panel efficiency is not the metric you use to choose solar panels for you home. Levelized cost or IRR would be a better figure to focus on.

Getting on to the solar modules, here are the most efficient solar modules in a few key categories:

  • 36% efficient Amonix solar modules hold the overall solar PV module efficiency record. However, these are made with concentrator solar cells and are not used in residential applications.
  • 21.5% SunPower solar modules hold the commercial solar module efficiency record. SunPower’s SPR-327NE-WHT-D modules are also the leading solar modules in solar module yield field tests, and other SunPower solar modules come in #2 and #3 in those tests. (For those of you to who this matters or is interesting, SunPower is a US-based solar panel company.)
  • 17.4% Q-Cells thin-film solar modules hold the record in this specific solar panel category. Thin-film solar panels are widely used, but not in residential applications. (Q-Cells was a German company, but it filed for insolvency in 2012 and was then acquired by the Korean company Hanwha.)
  • 17% First Solar thin-film solar modules claim the cadmium-telluride (CdTe) photovoltaic (PV) module conversion efficiency record. Again, these are generally not used for residential applications, but I think including them helps to reinforce my key point yet again. (First Solar, a US-based company, was actually the #1 solar developer and the #2 solar module manufacturer in the world last year. Despite a relatively low 16.1% record efficiency in this solar panels category at the time, First Solar does very well with these relatively cheap solar modules in certain applications.)
  • Just as one final example in order to show that the variation doesn’t stop there, 15.5% solar modules from MiaSolé hold the flexible PV solar module efficiency record. Naturally, in some applications, one doesn’t just need solar panels, one needs flexiblesolar panels. But, that probably isn’t you….

The takeaway point is:

Skip the focus on hypotheticals and irrelevant superlatives. Forget about what the “most efficient solar panels” are. Check on the solar installers in your area (you can get connected to them via our home page). See what they quote you. Ask them what solar panels they would use if you want to know. And compare your options to your heart’s content. Don’t go trying to find solar panels that were designed for NASA satellites.

By the way, the following chart from NREL isn’t fully up to date (solar efficiency records are broken quite frequently), but it gives you a good sense of the large variety of solar technologies:

Best Research Cell Efficiencies Most Efficient Solar Panels    Which Ones?

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About the Author

spends most of his time here on CleanTechnica as the director/chief editor. Otherwise, he's probably enthusiastically fulfilling his duties as the director/editor of Solar Love, EV Obsession, Planetsave, or Bikocity. Zach is recognized globally as a solar energy, electric car, and wind energy expert. If you would like him to speak at a related conference or event, connect with him via social media. You can connect with Zach on any popular social networking site you like. Links to all of his main social media profiles are on ZacharyShahan.com.



  • Robert Reed

    I’m interested in solar panels, but I’m hearing about new 3D panels that could represent a big advance. Should I wait for these cells to come out?

  • http://captainjack.ws Captain Jack

    A house has a lot of real estate space. I get that, but when you’re on a sailing yacht, you have very limited space. Currently in the market, I only see efficiencies of 6% – 13%. I would sell the farm for 44% efficiency. Is there any companies offering a solution that can stand up to saltwater and vibrations?

  • stillfiguringitout

    What is your take on a 24 panels LG 300 7.2 kw system with solaredge 7600 inverter for $20,664 vs. a 24 panels sunpower 7.848 kw system with SMA inverter for $24,364. Sun power has 25 year warranty vs. 10 year for LG.

    • David Kwong

      Which solar panel installation company service Tustin, CA is quoting 24 panels sunpower 7.848 kw system with SMA inverter for $24,364?
      The best power-performance guarantee in the industry – SolarWorld Sunmodule Plus SW 310 Mono panels has new 30-year linear warranty. The warranty guarantees power degradation of only 0.35% per year – that’s half the degradation
      rate of a traditional linear warranty. By the end of 30 years, they guarantee performance at 86.5%.

      • stillfiguringitout

        I had a few quotes for all sort of panels from different companies, but solar world wasn’t on of them. But all those companies do say sunpower is top of the line panels in efficiency and has one of the longest warranty 25 years where as most of them 10 years, and they are expensive for that reason. There are a few.

  • buellwinkle

    I have roof shape that doesn’t allow for many panels. I can fit about 20 panels. The installer only carries 250W panels. Are there any disadvantages to going with say 390W or 435W panels and less of them, Say 20 panels at 250W is 5KW, but with 435W panels, I can use say 11-12 panels to produce the electricity or is my math wrong. Or I can get much higher output with 20 panels. I would imagine the 435W panels are expensive, so don’t know if labor costs could offset it. Is there a higher wattage amount that’s cost effective per watt?

    • Bob_Wallace

      You’ve got a two question issue.

      First, can you fit enough panels on your roof to cover your needs using 20/250W or 12/435W. The answer lies not in the panel wattage rating, but in how many watts per square foot. If you’re space limited then you might want to pay a bit more per watt in order to get your power needs covered.

      Look up the size of each panel you are considering (width and length) and calculate the square footage and then divide that by the wattage. Or work out the array size of 20/250W and 12/435W arrays.

      If they both fit then move on to panel and installation costs.

      Calculate the cost per watt of each of the various panels. And get some rack prices for both approaches.

      Larger panels might save you a little labor costs. But most of the labor input is going to be the same. The time to get to the site will be the same. The cost of installing racks and wiring individual panels will be a bit lower. The time to design the system and to do the hookups to the service panel will be the same.

  • Joselito

    Which country has the best solar energy project in MW and with which solar panel product ( efficient ) ? Insteresting to know…

    • Bob_Wallace

      Which country is likely to lead in terms of most watts of solar installed? China is my guess.

      Which country is using the highest efficiency panels? That would be hard to determine. I suspect all countries are going to move to higher efficiency panels as they become available. Higher panel efficiency helps cut down other costs (racking, wiring, labor, shipping).

  • Mathiaslink

    What I’d like to have is a chart that shows the manufacturers and integrating area vs kWH vs cost to ascertain where the sweet spot is.

  • Ian Smith

    What these discussions forget to mention is that efficiency is just part of the equation. A 250W poly panel provides the same yield as a 250W mono panel. SunPower loves to quote their high efficiency cells but what is important to the end-user is how many kWh’s does my panel produce for the money I spent. Square area of the cells in the panel exposed to the sun times the efficiency equals watts.

  • John Dough

    This article is worthless without the date. Is this current or from 5 years ago?

    • Bob_Wallace

      Look at your address bar.

      2014/02/02

      The new format has dates on the ‘front page’ but they didn’t make it to the individual pages it seems. I’ll poke headquarters once more….

  • beelite

    Actually I think the price of solar panels have come down in recent years, for example i could buy a 200w or even 250w panel – today if I wanted – for £99, the problem is the solar inverters are very expensive in comparison to a regular inverter. I believe if the current price of solar inverters were to come down then the cost of a solar panel system would be greatly reduced. Although I look forward to the day when I can get a 500w panel for £99, or even – dreaming here – a 1kw panel for £99!

    • OnlyMe999

      not sure where you are finding your solar panels, they seem to be £122+ vat (£145) for 250w solar panels not £99.

  • Sadia Sheikh

    Informative article. Does the solar panel’s low efficiency also include inverter’s efficiency? since most inverters have low efficiency. Or inverter efficiency has to be take into account separately?

    • Bob_Wallace

      Inverter efficiency is very high. Mid to high 90% range.

  • AF Din

    Hello There,

    I still dont understand why the solar module/panel efficiency is an important factor for an end user like me. If a solar contractor offers me a 5kW system based on a certain number of panels (for example 20) of certain nominal wattage (for example 250 watts each), then why do I care for the efficiency of the individual module/panel? I have to look at the total figure of 5kW, thats it. Now who cares how many number of panels and with what efficiency as long as I get my 5kW. Which means if one contractor offers me a 5kW system consisting of 25 panels, each with 200W nominal output and 13% efficiency say at a price of $5000, versus another contractor who offers me a 5kW system consisting of 20 panels of 250W nominal output each with a 16% efficiency at a price of $6000, then I should definitely go for the former one ignoring the importance of the number and efficiency of panels, assuming I get an identical inverter in each case. Or am I making a mistake in my assumption somewhere?

    • Bob_Wallace

      If the cost to you is the same, and you have plenty of roof space then panel efficiency shouldn’t matter to you.

      Overall more efficient panels means less mounting hardware/racking and less labor. If there’s a cost for real estate then that plays in as well.

      • AF Din

        Thanks Bob to let me know your opinion which was pretty much in line with what I was thinking.

        I would definitely welcome the opinions of other people if they have something to add

        • Jola

          5kW is not nominal but maximum capacity, so there is no difference at full production, but at lower production you will get 20% less output from 13% efficient cells than from 16% efficient cells. If the panels payback time is 2 years, after 2 -3 years you will be better off with more efficient cells.

          • Bob_Wallace

            ” but at lower production you will get 20% less output from 13% efficient cells than from 16% efficient cells.”

            Can you explain that more fully?

    • http://sroeco.com/solar SRoeCo Solar

      You’re spot on AF Din. The efficiency is NOT an important factor for most end users. It really only matter when space is limited. No big mistakes in your assumption.

    • Evert VaVaVanVliet

      Things get trickier when one has less space, I wouldn’t be able to install 20 modules.

  • Gunawan

    My country have sun every day, maybe too much and very hot. Why no one produce it in mass and sell to my country? Indonesia…. we lack of electricity and electricity here down 6 hours every day. Deficit 350 MW in my town… Medan. Thanks…

    • joe

      smallest number of market share in indonesia . its not essential product. lack of green technology awareness . needs at least 5-10 years in developing awareness. why would people in indonesia invest min $10000 when they just pay average $50-100 a month in electric bill . the culture and mentality are the main problem in indonesia. import taxes in indonesia is very high. gov suppose to eliminate green taxes or give credits to support green technology

  • deepa

    to buy a solar is take more cost while looking others and power is high when only peak time

  • C Brighton

    Thanks for this worthwhile post. Has anyone done any recent life cycle analysis of solar panels? Which panels have the least environmental impact from materials used, manufacturing process, life expectancy and recycling?

    • Bob_Wallace

      I doubt you’re going to find that sort of study. Things are changing so fast and solar panels last so long.

      There are a couple of labs that evaluate different brands of solar panels for quality, to determine if financial organizations should loan to sites using specific brands. Don’t know if that info is made public.

      There are lifetime CO2 footprint studies, but they may not be up to date, probably aren’t up to date. We’re seeing lots of emphasis on bringing down the cost of panels so that means energy inputs are probably dropping.

      At this point perhaps the important thing is to emphasize that all solar panels are better than coal. And if you want good quality panels take a look at what is being used for large scale projects and go with those brands.

    • Matthew_Thompson

      @C Brighton: You are correct. This is a very insightful post. For a long time I have cautioned my boss about using $/W metric for PV module comparison. Sure it is an easy metric because the modules have a power rating and a cost. But that can lead to costly errors in the long run. A much better metric is offered by the Principal Solar Institute that is based on Lifetime Energy Production. It is energy that is sold, not power. People pay their electric bill by $/kW-h. You can run a model on each PV module that you might purchase, but PSI PV Module Ratings are have already done that. It is a great first-pass screening tool.

  • South Jersey Solar

    these efficiency records are outdated. I would have liked to see the article conclude with some estimates for $/w ranges of each, even if not accurate

  • SolarPod

    Another well research article. There is a myth that solar panel efficiency is doubling similar to semiconductor devices (MOSFETs). This article sheds good light into this myth.

    • JamesWimberley

      The halving story is the price. Efficiency gains by contrast are pretty slow. We will wait quite a long time yet for affordable 30% efficient panels.
      Efficiency is particularly important at high latitudes. The limit to British solar PV output, say, is space.

      • SolarPod

        Agreed. There are some who think the price halving is because of efficiency similar to MOSFETs. I was merely pointing out the price halving in solar is due to economy of scale.

        • JDL51

          And the collapse in price of the materials required for panel construction.

  • ronwint

    Here’s a module that’s not only efficient but also offers a better PTC to STC ratio (93.44%) than over 100 of SunPower’s solar module modules and a better PTC to STC ratio than nearly every other module on the CEC’s list. Plus, it offers a killer temperature coefficient rating of -0.27%/degree C. The bet part is that the systems that are equipped with these modules is nearly half the price of a SunPower system. We’re marketing these modules under the brand name of Hyper X Solar and we’ve begun shipping them all over the country.

    • A3Usolutions

      @ronwit, sir can you send me details and price list for the Hyper X

      email : a3usolutions@gmail.com

      Leo Tamayo, President & COO, A3U Solutions & Technologies-Philipiines

    • Joe

      sir can you also send me details and price list for the Hyper X modules.

    • george

      You might have someone spell-check your packages.html page, and change “Flashings” to “Flashing.” Maybe add some commas as well.

  • BV

    The key is not the $/kW. The main calculation is for Levelized Cost of Energy (LCOE) as only this calculations shows the true costs over the lifetime of a project. But it’s correct more efficient high quality panels may be better than cheap low efficient ones as they not only produce more but also last longer at a lower degradation factor.

    • http://zacharyshahan.com/ Zachary Shahan

      Agreed.

    • Kyle Field

      It’s the big 80 for 20 – finding the sweet spot of finding the best value to return equation. For my house, I was definitely lower on the pricing curve than I would have been if I were installing a large scale array that I would want to operate with a much lower failure rate resulting in paying slightly more for panels.

  • Sean

    high efficiency is really interesting for things like portable devices, or boats and caravans, as you dont have much space to work with.

    But it is true that most sales people want to throw emotional language like “best” and “most efficient” at you, but most of the time what people are really looking for is best return on investment.

    • http://zacharyshahan.com/ Zachary Shahan

      Yep, basically the point of this post.

  • JamesWimberley

    California solar consultant Sean Roe runs a solar information website including a comparative table of the performance of 13,000 solar modules on the market. http://sroeco.com/solar/table/

    He also offers sensible advice: the warranty is as important as the efficiency. If we all waited for next year’s better computer, we would live our lives without them. Is the deal you can get now a good one for you? If so, go for it.

    • http://sroeco.com/solar SRoeCo Solar

      I agree! ;-)

      (Thanks for the mention James. Glad you find my advice sensible.)

    • Jeffrey Simmons

      Although I agree that this advice has merit, especially for those who find the installations meet their needs and can pay/finance over a short term, I would say that, with the current pace of innovation, a more apt comparison would be with flat panel TVs where technological changes are more obvious. Efficiencies are quickly trending upwards. There will be a sweet spot where fewer and thinner panels would be needed (even replaced by roofing or other building materials) or a greater output would be attainable…all at a much lower cost.

      Unfortunately, many of the installations are financed on zero-down 20 year leases. THAT is problematic. Unless installers begin offering a path towards upgrading the system in 8 – 10 years, those installations of aging technology will likely depress the value of homes, not enhance them. (In comparison, twenty years ago it was 1994 and Yahoo was just founded, Microsoft released the beta version of Windows 95 and Intel’s 486 processor ruled!)

      No need to wait forever, just don’t pay early adopter costs…wait until the market matures a bit more before committing to zero-down, long-term leases!

  • Lindsay Wilson

    If you are short of space, it is pretty damn important. I payed for expensive high efficiency panels due to lack of space. Cheap panels got me about 2.4 kWp, as it is I’ve got 3.29 kWp and a far better outlook for degredation

    • http://zacharyshahan.com/ Zachary Shahan

      Yep, fully agree. But you didn’t get CPV panels :D

    • val

      Hi Lindsay, i am looking to buy good panels, may i ask what you purchased. and what watt panel you got.

  • Omega Centauri

    It goes beyond simple cost and nominal efficiency. Efficiency under what conditions? Some types have lower thermal coefficients (the rate output drops with increasing temperature), and this might make the difference in you live in a very hot (or cold) environment. Also how good does the output hold up when the angle on incidence is low?

    Speaking of the efficiency market. I haven’t heard anothing about Alta-Devices recently. These were the premium high efficiency Galium Arsenide products.

  • Troy Frank

    Getting solar panels that are the cheapest for the kilowatts that you want is not necessarily the right way to go. Efficient panels mean you need less of them, which can save money on racking, inverters, and labor time to string them them up. Total cost of the panels is only one variable in the overall project cost.

    Also gives you more flexibility later to add more, if you haven’t already filled your roof with low efficiency panels

    • Matt

      Well of course its the total system cost/number KWs. That is the starting point. Those non-panel cost are making up more and more of the total these days. And if you are off-grid you might decide that getting higher total Kws is worth more $/Kw. And a higher $/Kw for a good installer using good quality panels. But total $/Kw is a good starting spot.

    • http://zacharyshahan.com/ Zachary Shahan

      ++

      • Folatt

        Zachary, your nrel graph is old. Update it.

    • Bob_Wallace

      Here’s a nice little graph that underscores your point.

      Racking, cables and labor is 62% of the total. Panels are 22%.

      More efficient panels will mean large installation savings.

      Additionally, more efficient cells save on panel manufacturing and shipping costs. More electricity for the same amount of frame and cover glass. For the same amount of time and labor to assemble the panel. Packing material and handling costs.

      • http://zacharyshahan.com/ Zachary Shahan

        Nice. Thanks. :D

      • Kyle Field

        Wow…this is interesting. For my install, the cables and racking were very inexpensive – just a few hundred dollars. Inverters and Modules were the bulk of the expense. Installation labor, sales overhead, engineering and electrical were all minimized by doing the majority of the design and procurement work myself then working directly (under the table) with an individual installer to wire it up.I learned a lot more and saved some cash.

        I am surprised that there isn’t a slice of the pie for the aforementioned sales, electrical and engineering…this must be a german pie as our american ones are much more expensive :/

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