Driving forward in the race for highly efficient solar cells, First Solar says it has converted 22.1 percent of the energy in sunlight into electricity using experimental cells made from cadmium telluride—a technology that today represents around 5 percent of the worldwide solar power market. The company’s commercial line of solar cells has reached an energy conversion efficiency of 16.4 percent. The theoretical efficiency limit for cadmium telluride cells is above 30 percent—significantly higher than that of conventional silicon. (Today’s commodity silicon-based solar panels have efficiencies between 16 and 18 percent; their theoretical limit is thought to be well below 30 percent.) First Solar, which is the only major manufacturer of cadmium telluride solar panels left in the United States, is working to bring commercial solar panels closer to that limit. “The gap between what’s theoretically achievable and what’s out there today has been pretty broad,” says Raffi Garabedian, First Solar’s chief technology officer. “We are closing that gap at a breakneck pace.”