A signiﬁcant conversion effort is predicted to take hold in the photovoltaic (PV) industry that would result in higher solar efﬁciencies for at least 30 percent of crystalline silicon (c-Si) cells and modules by 2015, a potential game changer that also could be the industry’s best hope to prevent further price and margin erosion, according to an IHS iSuppli PV Perspectives Brief from information and analysis provider IHS.
So-called high-efﬁciency solar units will account for just 14 percent in 2011 of the total market for c-Si cells, the components in solar panels responsible for converting the sun’s energy into electricity. Instead, the bulk of the market—86 percent—will be made up of standard-efﬁciency cells utilizing older technology.
The market share of high-efﬁciency cells, however, could climb very quickly in four years to 31 percent, if the industry employs any number of conversion technologies to achieve greater solar adaptation—a prospect that appears to be making headway in the industry. Most of the highefﬁ ciency volume in early 2011 is from California-based SunPower Corp. and Japan’s Sanyo Electric Co. Ltd., but several other players also are expected to roll out their offerings during the course of the year.
A higher-efﬁciency cell is one that employs advanced conversion techniques to increase solar efﬁciency anywhere from 0.3 percent to as much as 5 percent. A module deemed 15 percent efﬁ cient, for instance, could result in a boosted efﬁciency rating of 15.3 percent on the low end, or rise by as much as 20 percent if it derived the maximum improvement.
A big challenge to switching is the higher price involved in producing higher-efﬁciency cells, which could involve a price markup of 10 to 15 percent in a panel that enhanced efﬁciency from, say, 16 percent to 19 percent. Conversion efﬁciency initiatives were not a priority in the past two years as the PV industry concentrated on fulﬁ lling surging demand for existing product. But given the continuing retreat of solar prices—down at least 25 percent this year—top module and cell suppliers are realizing that higher-efﬁciency techniques could be a key competitive weapon in the future to achieve market differentiation and superior product. The strategy, IHS believes, also could slow steadily eroding PV prices so that reasonable proﬁts can be made.
Already, negative perceptions on conversion viability appear to be changing for the better as the techniques become less risky and more cost effective to implement, thanks to the advocacy work of research labs like ECN and Fraunhofer, equipment companies like Applied Materials Inc. (AMAT) and Manz Automation AG, and cell materials suppliers like DuPont, which recently bought Innovalight and their Silicon Ink technology to expand its portfolio.
In general, conversion techniques involve letting in a greater amount—or a broader spectrum— of light while reducing recombination losses, in which holes and electrons recombine before being extracted. While most conversion techniques have been around for some time—one or two decades in some cases—it is only now that the technologies have achieved serious attention for broader commercial implementations.
The most prominent of the new technologies are those that minimize front-side metal contacts known as busbars and ﬁngers. While the contacts are vital to the solar cell’s operation, they also block the sun at the same time—reason for conversion technologies to be employed.
A broad array of solar conversion technologies is available today, including broad side contacts, heterojunction cells, passivation layers, selective emitter technology, new light-trapping techniques, smaller front-side metallization and bi-facial cells. There are also various efforts occurring in the research and development stage, including hot-carrier technologies, 3-D cell structures and new energy-conversion layers based on rare earths and silicon nanoparticles.
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