In the world of solar photovoltaics, big money is spent on small gains, with companies spending millions to push the conversion efficiency of their cells up a few 10ths of a percent. Silicon solar cell maker Suniva says it has set a new record by achieving more than 20 percent efficiency with screen printed solar cells. Verified by the DOE’s National Renewable Energy Laboratory, these cells represent a considerable gain over Suniva’s current ARTisun cell technology which has produced a verified efficiency of 18.5 percent. Conversion efficiency refers to the percentage of sunlight converted into electricity, a critical metric in reducing solar energy costs.
Suniva’s goal is to commercialize cells that are more than 20 percent efficient by 2010. Today’s achievement represents one part of Suniva’s three-pronged approach to pushing costs down while boosting efficiency. In addition to improving the contact performance of screen-printed gridlines, Suniva is working to capture more photons at the highly energetic blue end of the spectrum and develop an improved dielectric to reduce the number of electrons that recombine before being sent off the cell as electricity.
It’s a big challenge to go after both efficiency and cost. The thin-film players have largely forgone high efficiency, settling on a meager 10 or 12 percent, in favor of dirt-cheap production costs. Meanwhile, the cream of the silicon-based solar crop are pushing up efficiency regardless of cost. SunPower, perennial claimant of the world’s most-efficient commercial solar panel, set a new record earlier this year with a five-inch prototype solar cell boasting 23.4 percent efficiency.
Like many solar manufacturers, Suniva has accumulated a sizable stack of supply and customer agreements. The company has signed a $300 million polysilicon supply deal with REC. On the customer side, Suniva has promised almost a billion dollars in solar cells — $500 million worth for Solon AG and $480 million for
REC Titan Energy, both large solar module makers.