Archive for September, 2010

Advances in solar energy efficiencies have so far been made with irregular surfaces, thinner tabbing between cells, more optically perfect glass and even special coatings, but now Stanford engineers say the best efficiency is via ultra-thin polymer films inside solar cells that allow more “bounce room.”

Add to that a slightly rougher surface, such as is achieved with black silicon, and efficiencies begin to approach a rating that is 10 times more than conventional wisdom suggests is possible.

What does conventional wisdom suggest? First, solar cell efficiencies are proscribed by the materials used; that is, each material, or combination, has a natural band gap, or filter, which prevents certain wavelengths of radiant energy from being absorbed and used.

Efficiency is also hampered by electrical resistance in the semiconductor, in the wiring that connects with the inverter, and in the inverter itself.

Where Stanford scientists have triumphed is in keeping the photons inside the solar cell long enough to extract the maximum energy available. As Shanhui Fan, associate professor of electrical engineering, said, “The longer a photon is in the cell, the better chance it will get absorbed.” (People who feed mice to snakes already understand this principle, unfortunately).

During the final week in September, in Proceedings of the National Academy of Sciences (PNAS), Fan talked to a Stanford University reporter and noted the dual nature of photons, which can exhibit as particles or waves (the famous “double-slit experiment documented by Thomas Young). stanford grounds

This led, naturally, to an experiment in which Fan and postdoctoral researcher Zongfu Yu (the lead author of the PNAS paper) tried to determine if the conventional limits also held true at the nanoscale level.

Without getting into confusing detail, it seems that light at ‘subwavelength’ scales (Yu’s word) can be confined for longer periods of time than light at the macro level, thus also extending the energy absorption rates and efficiency.

The final material arrangement Yu arrived at, which consisted of organic thin film between two “cladding layers” with a single, rough layer, achieved a 12-fold increase in solar efficiency after the parameters of the various layers were adjusted according to mathematical simulations made beforehand.

Of course, neither Yu nor Fan are revealing the precise formula, but Fan admits that, if one does it “right,” there is enormous potential for solar cell efficiency that could lead to vast improvements throughout the solar industry.

Photo Credit: Rob Pongsajapan & Lee Brimelow via Flickr CC

Comments Off

Enbridge Announces Grand Opening of the Largest Photovoltaic Facility in the World

Posted in September 30th, 2010

by Solar Power Digest in Nanosolar

SARNIA, ONTARIO–(Marketwire – Sept. 30, 2010) – Enbridge Inc. (TSX:ENB) (NYSE:ENB) and First Solar, Inc. (NASDAQ:FSLR) have completed the expansion of the Sarnia Solar Project from 20 megawatts of capacity to 80 megawatts (MW) making it the largest operating photovoltaic facility in the world.

To celebrate this milestone, Enbridge will hold a Grand Opening celebration in Sarnia, Ontario. Enbridge and First Solar representatives along with the Ontario Energy Minister, Hon. Brad Duguid, will be on-hand after the formalities to speak with the media.

Comments Off

Mars Chocolate Headquarters First Private Sector LEED Commercial Interiors Gold Facility in New Jersey

Posted in September 30th, 2010

by Solar Power Digest in Nanosolar

HACKETTSTOWN, N.J., Sept. 30 /PRNewswire/ — Mars Chocolate North America announced today that its corporate headquarters facility located in Hackettstown, New Jersey, is the first private sector Commercial Interiors project in New Jersey to receive LEED Gold Certification—an internationally accepted benchmark for designing, constructing and operating green buildings—from the U.S. Green Building Council. The office is also the first existing Mars site globally to achieve this designation.

LEED Gold certification is the culmination of months of work to incorporate more than 30 Green Building strategies into the renovation of the 100,000 square foot office facility. Enhancements include the installation of water-conserving fixtures that reduce water usage by more than 30 percent; a reduction in energy use by 15 percent through the use of a newly upgraded Building Energy Management System, variable frequency drives and energy-efficient lighting and controls; an upgraded roof utilizing a highly reflective roofing material that reduces heat gain to the building; the utilization of more than 20 percent recycled content in materials, from carpet to ceiling tiles; and the installation of bike racks and preferred parking for carpools/vanpools.

“The achievement of LEED Gold certification at the Mars Chocolate North America headquarters is a tremendous achievement and a testament to Mars’ commitment to the environment and to the communities in which we conduct business,” said Todd Lachman, president of Mars Chocolate North America. “This accomplishment joins a host of others that comprise our larger sustainability strategy focused on sourcing, operations and our brands.”

LEED certification of the Hackettstown corporate headquarters follows closely on the heels of the site’s November 2009 opening of the largest ground-based solar facility installed in New Jersey. The solar garden is comprised of more than 28,000 ground-mounted solar panels on 18 acres adjacent to Mars Chocolate North America’s headquarters, where more than 1,200 associates work and M&M’S® Brand Chocolate Candies are manufactured. The solar garden provides 2 MW of power during peak hours, which is equivalent to approximately 20 percent of the plant’s peak energy consumption. It reduces carbon dioxide emissions by more than 1,000 metric tons, equivalent to removing 190 vehicles from the road each year.

Mars Chocolate North America’s commitment to sustainability extends beyond its New Jersey headquarters. The company’s Waco, Texas, manufacturing plant was recognized by the federal Environmental Protection Agency for its use of methane gas from the local landfill to replace 60 percent of the site’s natural gas usage. Several of the company’s manufacturing facilities also recycle 95 percent of their waste, significantly reducing the amount of waste sent to landfill.