Scientists from the nearby National Renewable Energy Laboratories were on hand at the forum to discuss their own breakthroughs in concentrator-cell efficiency, and compare the milestones to those in other realms. Principal scientist Sarah Kurtz said that NREL's recent announcement of 40.8 percent efficiency for a multijunction two-terminal concentrator cell implemented in GaAs brings the industry close to the grail of cost-competitiveness with other electricity-generating methods. Concentrator architectures carry the additional advantage of using less silicon than direct PV solar panels, she added.
Dean Levi, who manages electro-optical characterization at NREL, pointed out that silicon shortages in the single-crystal world are lessening because silicon suppliers finally are ready to ramp up to perceived needs of PV startups. For many years, he said, silicon ingot suppliers were reticent at producing as many wafers as the industry claimed, having been burned during semiconductor booms. By last year, new investments and orders showed that the PV boom was real, and the shortages should be over by next year. Levi said that the global PV market should reach $150 billion by 2011, representing more than 20 GW of generated electricity.
While concentrator cells remain in front on electrical efficiency, Levi said SunPower had shown 25 percent efficiencies for single-crystal cells, and new thin-film concepts using compounds such as copper-iridium-gallium-selenide (CIGS) or cadmium-telluride, could achieve efficiencies greater than single-crystal silicon. Levi said that deposition concepts were as relevant as materials. New methods such as a spray-on printing method for CIGS, developed at NanoSolar, could achieve as many gains as new thin-film materials.