One of the most common comments that the Solar Choice Energy Brokering team hear from our customers relates to the issue of monocrystalline vs polycrystalline (or ‘multicrystalline’) solar panels. Although monocrystalline panels had the initial advantage of being seen as the superior technology in the Australian market, as time goes on and both technologies improve, it becomes increasingly apparent that the the quality and reliability of the manufacturer is far more important than which of the two technologies is chosen.
What’s the difference? Monocrystalline vs Polycrystalline solar panels
The typical monocrystalline solar cell is a dark black colour, and the corners of cells are usually missing as a result of the production process and the physical nature of monocrystalline silicon. Polycrystalline, on the other hand, is identifieable by its signature light or dark blue colour, but not uniformly so: some patches are lighter than others. The differences in appearance come about as a result of the manufacturing process. (Read more: The manufacturing and science behind solar cells.)
When solar PV first boomed in Australia in 2009-2010, monocrystalline solar panels were thought to be superior to polycrystalline solar panels. There were a number of reasons for this thinking. Monocrystalline solar cells have historically had a higher peak efficiency, and were more readily available than polysilicon solar cells. The blanket statement that monocrystalline panels are better than polycrystalline cells, however, is not accurate. Each panel and its manufacturer should be considered on a case-by-case basis.
Some comparisons and examples
It is not difficult to find examples that illustrate the above points. The below comparisons are not intended to imply that one panel brand is of higher quality than another, but simply to show that some polycrystalline solar modules are more efficient than monocrystalline ones.
First, to compare mid-range products of comparable quality and price, GermanSolar brand 60-cell monocrystalline Premium Line panels have a maximum efficiency of about 15.47%, whereas Conergy’s polycrystalline PowerPlus modules have a maximum efficiency of 14.13%. This is not far off from the 14.9% that Sun-Earth’s 190W monocrystalline module boasts.
It is possible to see the same trend in high-end modules as well. For example, premium US manufacturer Sunpower’s monocrystalline panels see peak module efficiencies of up to 20.7% (22.8% efficiency for individual cells), a few percentage points ahead of Suntech’s polycrystalline Pluto technology–certain cells of which were recently confirmed as having hit 20.3% in lab conditions. Although commercially produced modules using Suntech’s Pluto technology will inevitably have lower peak efficiencies than this impressive rate, it still serves to demonstrate that monocrystalline is not an intrinsically better choice than poly.
A note about solar panel efficiency: How important is it for your system?
Remember that, especially for buildings with ample roof space, a panel’s peak efficiency is not the primary consideration for most solar system owners-to-be. Unless there are no budgetary constraints, it is more important to consider the system as a whole, balancing price with quality. In some cases, a high peak efficiency can act as a sales point, and proof that the product is ‘high-tech’ or cutting edge and therefore deserving of a higher price tag. For the budget-conscious, however, the number to look at would be dollar per watt for the entire installed system.
In the end, the cost and performance of your system will depend not only on the panels you use, but also your solar inverter, your installer’s labour costs, and the orientation of your home’s roof and tilt angle of your panels.
Looking beyond the module and its efficiency: The importance of the company behind the product
Although quality technology is important in selection of solar panels, it is also critical to keep in mind that both monocrystalline and polycrystalline silicon solar cells are proven technologies, and one should not automatically be considered better than the other. Manufacturing equipment for silicon wafers is now more readily available now than it ever has been in the past, however, so panels are relatively easy for companies to manufacture. A key differentiating factor between the quality manufacturers and the bottom-line ones is whether the company in question invests in research and development (R&D). R&D investment by a manufacturer is usually indicative of the company’s commitment to creating innovative and quality products, but it also shows that the company is planning to be in the game for the long-term, and is not a fly-by-night operator.
For most households, balancing affordability with reliability is key. Solar power systems are ordinarily expected to continue operating for 30+ years; solar panel warranties generally cover products for up to 25 years. Warranties are will only continue to be serviceable if the manufacturer behind them remains a solvent company. Although it is impossible to know for sure what will happen a quarter century in the future, when selecting a panel, it is still advisable to try to imagine whether the product’s manufacturer is likely to be around at that point in time, just in case something goes wrong in the meantime. Otherwise, if the panels need repairing, the cost could end up being greater than an an initial investment in more reputable product would have been.
(Read more: Questions to ask your solar panel manufacturer.)
© 2012 Solar Choice Pty Ltd
He holds a master's degree in Environmental Management from UNSW, and a bachelor's degree in Philosophy from Bridgewater State University in his native Massachusetts.
He currently works remotely for Solar Choice from New York City.
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