Oct. 31, 2012 at 3:10 PM ET
An out-of-the-lab solar-power system has successfully shown it can convert more than a third of the sun’s direct sunlight into electricity, a new record for a technology that focuses sunlight akin to the way school kids burn leaves and ants under magnifying glasses.
The record of 33.5 percent efficiency was announced Tuesday by Amonix, a manufacturer of concentrator photovoltaic (CPV) solar power systems. The achievement was confirmed by the National Renewable Energy Laboratory and breaks the previous record of 30.5 percent, also held by Amonix.
Other manufacturers of CPV systems have also achieved similarly high efficiencies. Semprius reported a slightly higher 33.9 percent efficiency in January, for example, “but it was not verified by an accredited lab,” Sarah Kurtz, a scientist at NREL who supports the CPV industry, told NBC News.
Likewise, the military's Defense Advanced Research Projects Agency reported an efficiency of 42.8 percent for lab-scale solar technology in 2007.
The breakthroughs in efficiency meet a long-held Department of Energy goal of “achieving a third of the sun efficiency,” Kurtz noted.
Amonix’s record is also “quite a substantial boost” over other photovoltaic efficiencies of around 20 percent reported by traditional flat plate solar panel manufacturers such as SunPower, she noted.
“The difference means that if you have a square meter of area that you can mount a solar panel on, you will get more energy out of the Amonix or some other concentrator module compared with what you will get from a flat plate,” Kurtz said.
The technologies, however, are different. Solar concentrators use lenses and mirrors to focus direct sunlight on a small area, which allows manufacturers to use less silicon and other semiconductor materials to convert sunlight into electricity.
This also allows manufacturers to use more expensive, yet more efficient, semiconductor materials than silicon, such as in Amonix’s multijunction cells, and remain economically competitive.
But concentrator technology requires direct sunlight. It doesn’t work well under cloudy skies — “if you try to use a magnifying glass on a cloud day, you wouldn’t be able to burn a leaf because the light is coming from all different angles and so you can’t focus it all onto one spot,” Kurtz explained.
Traditional flat plate photovoltaic systems, by contrast, can still work with diffuse light.
The difference means that concentrator technology works well in sun-splashed markets such as Phoenix, but flat plate panels may be a better choice for Seattleites.
Big picture, the advances in solar technology combined with falling costs are begging to make the technology economically attractive compared to traditional fossil fuels such as coal. The question, Kurtz said, is whether companies and individuals will pay an up-front premium for renewable energy.
“It’s like with compact fluorescent light bulbs you can demonstrate over the course of the lifetime of a bulb, it is cheaper to operate the compact fluorescent, but people are hesitant to spend the up-front cost, so there are barriers to adoption,” she said.
One way to help people to get over the barrier is tax incentives, which have become increasingly controversial.
“It will reduce our energy usage of the world in the long-term,” Kurtz said, “but it does require people to take an intentional step upfront to invest.”
— via Clean Technica