You may have come to picture solar panels as rectangles angled toward the sun atop homes and businesses across the country. What you’repicturing is most likely an array of silicon-based solar panels — whichcome in two common “flavors,” monocrystalline and polycrystalline. Butnext time you see such a system, take a good look… maybe even snap apicture. There’s an emerging kind of solar panel that could soon maketoday’s standard model look as old as your dad’s Walkman: thin-filmsolar. There’s been a lot of talk about this kind of technology lately, so we thought it wise to explain a bit about solar thin-film technology.
Thin-film panels are most commonly made of cadmium telluride (CdTe)or copper indium gallium selenide (CIGS) — two compounds that havesemiconducting properties similar to silicon. When applied to glass,they become rigid and unable to bend. But if applied to plastic, they’re flexible and can be placed on non-flat surfaces. Additionally, becauseof their thinness, thin-film panels require less material and are alsocheaper to manufacture than conventional silicon-based panels.
So, to recap: thin-film panels are cheaper, lighter and, in someinstances, flexible. So why don’t you have them on your home? The maindrawback is thin film’s relatively lower efficiency rate.
Simply put, the silicon-based panels available today generate moreelectricity per square foot than their thin-film counterparts. Thin-film makers are continually closing this gap. But the fact remains that, all else equal, you’ll need more roof space for a thin-film solar installation to get the same amount ofelectricity out of silicon-based solar installation. Since homes tend to have relatively small roofs, hence the preference for silicon-basedpanel for residential applications. (Thin-film is an increasinglypopular option when it comes to large scale solar installations,however, where space constraints aren’t as much of a concern.)
So, will silicon-based panels go the way of the Walkman? Time willtell. If manufacturers can boost the efficiency of thin-film solarpanels while continuing to reduce manufacturing costs, this might be aplausible outcome. But for the time being, if you’re interested in asolar energy system for your home, chances are silicon-based panels areyour best bet.