Solar remains the most viable renewable energy option for most households in America. In fact, unless you have falling water on your property, or live in an area where zoning allows for wind towers, solar may be your only option (save geothermal heating and cooling). Solar is where great incentives are, too. Federal tax credits and a growing number of state and local programs offer substantial assistance in purchasing a solar electric system.
For those in states with the best rebate programs-and therefore a developing solar installation industry -- it's typically best to find a qualified installer to get the job done. You may even find that the rebates are dependent on this. In other areas where a solar industry is yet to develop, it may require a strong DIY sensibility or the patience of bringing local electrical contractors up to speed on solar. In either case, it will help to know your brands.
To that end, I've highlighted three of the best-in-class photovoltaic modules, after looking at Sharp, Kyocera, Suntech, Sanyo, SunPower and others. All of these utilize crystalline photovoltaic technology. Amorphous modules like Uni-Solar have their perks, but are neither most efficient nor least expensive. Thin-film technology is noteworthy for its very low cost (and low efficiency) but is not readily available at the residential installation level. Yet.
SunPower modules are the most efficient solar panels on the market, coming in at an amazing 19% efficiency (18% on their signature black modules). While these numbers may seem low, they are approximately 1/3 better than the average crystalline module at converting available sunlight into electricity.
Further, SunPower signature black modules blend very nicely into most roof applications, making them a more aesthetically pleasing option for many.
It should be noted, however, that SunPower modules are not available for individual purchase. They must be purchased through the manufacturer-qualified dealer/installer network.
Westinghouse recently acquired and renamed Akeena Solar's unique Andalay product. According to the company's CEO, Barry Cinnamon, the panels are true AC modules, because they deliver household current directly. Normally, solar panels deliver DC power that needs to run through an inverter in order to be usable in typical household applications. But the Westinghouse units have micro-inverters built in. They also come with a relatively easy plug-n-play racking system that entails, according to their website, 80% fewer parts.
The significant benefit of the AC technology is that it brings great flexibility to system size and design. No longer must modules be run in "strings" to achieve necessary voltage output. This brings two benefits. First, any number of modules can be designed into a system, not just increments of, say, four. Secondly, the issue of shading is dramatically reduced -- affecting only the modules that are shaded, not the whole system.
It's worth noting that you can also add micro-inverters to many standard DC solar panels, with products from Enphase and others.
Westinghouse modules are available through the Westinghouse dealer/installer network and through participating Lowe's retail centers.
The Kyocera KD Series solar modules hold their own in terms of quality. They achieve a high level of efficiency (up to 16% compared to an average of 12-14%), have a 20-year warranty--and they do all of this for typically 10% less than similar products from other brands, depending on manufacturer-dealer pricing arrangements.
Kyocera modules are readily available from most suppliers.
Bill Giebler has been in the green products business since 1990 and is currently the Director of the Retail division of Real Goods.
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