Solar Power Advances Keep Coming in 2008

Scientists and engineers continue to find ways to improve the efficiency and economics of solar power, which many are eying as one possible way to help curb greenhouse gas emissions and climate change.

Just last month, Sandia National Laboratories and Stirling Energy Systems (SES) set a new world record for solar energy conversion efficiency. Their "Serial #3" solar dish reached a 31.25 percent net efficiency rate, breaking the previous record of 29.4 percent set in 1984.

Efficiency measures the ratio between the energy a solar dish produces versus the total solar energy hitting the dish.

"Gaining two whole points of conversion efficiency in this type of system is phenomenal," said Bruce Osborn, president and CEO of SES. "This exciting record shows that using these dishes will be a cost-effective and environmentally friendly way of producing power."

Osborn added that SES is now working to prepare the system, dubbed the "SunCatcher," for commercial use.

The SunCatcher system boosted past efficiency figures through a combination of improved optics, a more effective radiator, a new and high-efficiency generator and perfect weather at Sandia's National Solar Thermal Test Facility in New Mexico.

"It was a 'perfect storm' of sorts," said Chuck Andraka, lead Sandia project engineer. "We set the record on Jan. 31, a very cold and extremely bright day, a day eight percent brighter than normal."

During the two-and-a-half-hour-long test, the SunCatcher system generated 26.75 kilowatts of electrical power. SES has already signed agreements with Southern California Edison and San Diego Gas & Electric, which are interested in using the system for power generation. Those agreements call for up to 70,000 solar dish systems that could generate as much as 1,750 megawatts of electricity.

Other recent advances in solar technology include improvements in organic solar cells, a prototype device that uses solar energy to convert carbon dioxide into carbon monoxide that helps generate hydrogen fuel and the possibility of actually printing solar cells.

Although the demand and cost of silicon for solar panels has limited solar power's widespread adoption till now, new innovations are regularly paving the way for greater use. IBM, for example, has begun selling its waste silicon wafers from the semiconductor chip manufacturing process to makers of solar panels.

The solar power industry is expected to grow rapidly as advances lead to ever cheaper and more efficient technology. The sector has grown six-fold since 2000, and global grid-connected solar energy increased by 50 percent in 2006.

While solar energy remains a small portion of the world's grid-based electricity, it is expanding especially rapidly in countries like Germany and Japan. In 2006, China emerged behind both those nations as the third-largest producer of solar cells, passing the U.S.

"Solar energy is the world's most plentiful energy resource, and the challenge has been tapping it cost-effectively and efficiently," said Janet Sawin, a senior researcher at Worldwatch. "We are now seeing two major trends that will accelerate the growth of (photovoltaic cells): the development of advanced technologies, and the emergence of China as a low-cost producer."

The global production of solar photovoltaic (PV) cells grew by 41 percent in 2006, according to Worldwatch. And, while solar energy connected to the power grid system remains a small part -- less than 1 percent -- of the world's electricity production, it expanded by nearly 50 percent in 2006.

Advances in thin-film solar systems, which require less costly silicon, could help drive those numbers upward even more in coming years.

"The conventional energy industry will be surprised by how quickly solar PV becomes mainstream -- cheap enough to provide carbon-free electricity on rooftops, while also meeting the energy needs of hundreds of millions of poor people who currently lack electricity," said Sawin.