Flexible Solar Power Shingles Transform Roofs From Wasted Space To Energy Source

ScienceDaily

Monday, June 8, 2009

A transparent thin film barrier used to protect flat panel TVs from moisture could become the basis for flexible solar panels that would be installed on roofs like shingles.

The flexible rooftop solar panels – called building-integrated photovoltaics, or BIPVs – could replace today’s boxy solar panels that are made with rigid glass or silicon and mounted on thick metal frames. The flexible solar shingles would be less expensive to install than current panels and made to last 25 years.

“There’s a lot of wasted space on rooftops that could actually be used to generate power,” said Mark Gross, a senior scientist at the Department of Energy’s Pacific Northwest National Laboratory. “Flexible solar panels could easily become integrated into the architecture of commercial buildings and homes. Solar panels have had limited success because they’ve been difficult and expensive to install.”

Researchers at PNNL will create these flexible panels by adapting a film encapsulation process currently used to coat flat panel displays that use organic light-emitting diodes, or OLEDs. The work is made possible by a Cooperative Research and Development Agreement recently penned between Vitex Systems and Battelle, which operates PNNL for the federal government.

PNNL researchers developed the thin film technology in the 1990s. At the time, the lab’s team investigated 15 possible applications, including solar power. Vitex licensed the technology from Battelle in 2000 and focused its initial efforts on developing the ultra-barrier films for flat-panel displays. Now PNNL and Vitex are taking a hard second look at solar power.

The encapsulation process and the ultra-barrier film – called Barix™ Encapsulation and Barix™ Barrier Film, respectively – are already proven and effective moisture barriers. But researchers need to find a way to apply the technology to solar panels that are made with copper indium gallium selenide, called CIGS, or cadmium telluride, called CdTe.

Under the agreement, researchers will create low-cost flexible barrier films and evaluate substrate materials for solar panels, which are also called photovoltaics, or PVs. Both the film and substrate must be able to survive harsh ultraviolet rays and natural elements like rain and hail for 25 years.

The agreement also calls for researchers to develop a manufacturing process for the flexible panels that can be readily adapted to large-scale production. If successful, this process will reduce solar panel manufacturing costs to less than $1 per watt of power, which would be competitive with the 10 cents per kilowatt-hour that a utility would charge.

“Vitex is proud to continue its long, successful relationship with PNNL,” said Martin Rosenblum, Vitex’s vice president of operations and engineering. “Vitex is excited to further its Barix™ technology’s proven barrier performance for photovoltaics toward mass manufacturing. Together, we look forward to creating a product that will help alleviate America’s dependence on foreign oil and increase America’s access to an abundant renewable energy source – the sun.”

Battelle, which is the majority shareholder of Vitex, is optimistic that this research agreement will contribute to a new way of generating solar power. Battelle recently increased its investment in Vitex for new state-of-the-art thin film encapsulation equipment and expanded its intellectual property portfolio.

“We’re confident that Vitex will be uniquely positioned to help meet the demand for flexible solar panels, OLED displays and lighting that should rise along with the economy,” said Martin Inglis, Battelle’s chief financial officer.

PNNL’s research efforts will be paid for with up to $350,000 from the DOE’s Energy Efficiency and Renewable Energy Technology Commercialization Fund. Last year, DOE announced that up to $1.5 million from the fund would be available to PNNL for projects that help commercialize technologies that reduce energy use or tap renewable energy sources. Because the fund requires commercial partners to match funding, Vitex will provide up to $350,900 of in-kind labor, equipment and materials for this project.

“Revelry by the River” Honors Some, Inspires All

ENN.com
M Molendyke
Friday, June 5, 2009

On a balmy summer night this week, the kind perfect for reflecting on the beauty and vitality of nature, supporters of Solar One gathered to champion just such a vision at the Revelry by the River event.

Solar One stands as a center for environmental conservation and learning, and since 2004 has been reaching out to students in the city to promote green learning and living. “Solar One is a leading environmental organization that addresses issues of sustainabiliy in the urban environment through the many programs we offer. These include our K-12 enrichment courses that focus on renewables, sustainable design, water ecology and horticulture; our green collar job training programs in building performance, PV (solar) installation, deconstruction, horticulture and youth green entrepreneurship; our solar advocacy program; and our solar powered arts festival” said director Christopher Collins in a statement made to ENN.

The fundraising efforts held on Tuesday June 2, 2009 were in support of the Solar Two project, Solar One’s big brother. Solar Two will be New York’s “Green Energy, Arts, and Education Center”, the city’s first carbon- neutral, net- zero energy use building. “Solar 2 will showcase state-of-the-art green building design and technology while operating as a thriving center for diverse environmental activities” outlined executive director Christopher J. Collins in a Director’s Letter given to attendees. In the same address, Collins also noted that “Solar 2 will embody our organization’s mission to provide people of all ages with the vision, knowledge and resources to achieve an environmentally
sustainable future.”

Chaired by H. Hartley du Pont and Jane Steiner Hoffman, the event brought together leaders from the conservation community as well as the most environmentally committed of the New York glitterati. Among the attendees were Governor George Pataki, actresses Lake Bell and Brooke Shields, and Real Housewives of NYC’s Alex McCord. “Revelry By The River” took time to hand out three honors to outstanding contributors to Solar Two and other environmental causes.

First, bank HSBC was honored for its $100 million contribution to a variety of environmental causes as well as its commitment to being carbon neutral (it reached this goal in 2005). Accepting the Sustainability Achievement Award, Vice President of Human Resources Suzanne Brienza thanked Solar One for introducing HSBC as a “corporate leader in doing the right thing”.

Actor Matthew Modine accepted the Environmental Stewardship Award in recognition of his founding of the Bicycle For A Day initiative, a foundation committed to promoting increased bicycle use for the dual benefit of reducing auto emissions and promoting human health and fitness. Said Modine in his acceptance speech, “there should not be a building in the US that does not incorporate the technology and knowledge that we have today” in order to promote green living.

Kathleen “Kick” Kennedy, granddaughter of Robert Kennedy, charmed the supportive crowd with her lighthearted acceptance of the Young Environmentalist Award for her work with the Waterkeeper Alliance and her recent appearance in the film Grand Canyon Adventure. Opening with a joke to illustrate that “solar power is no laughing matter”, Kick thanked her family and the audience for their support in her environmental efforts. ENN spoke to Kick before the ceremony, where she expressed her ardent support of public officials who encourage environmental conservancy in legislation and noted that “there should be more stringent laws” to prevent air and water pollution.

As the sun set over the New York City skyline, guests departed with the themes of the night in their minds: Education, conservancy, and the inspiration to do the right thing. The event was a “huge success, both financially and in terms of our overall mission of education on the issues of sustainability in the built environment” remarked Chris Collins.

Solar Tech: Not Just on the Roof Anymore

New York Times
Anne Eisenberg
Friday, April 29, 2009

PHOTOVOLTAIC cells are already a familiar sight on rooftops. But one day, miniature cells may also be found in more unconventional places: power-generating windows, car sunroofs or even awnings.

The new technology is the work of a researcher and his colleagues who developed a way to print ultrathin, semitransparent and flexible cells on plastic, cloth and other materials. If the technology succeeds, it may provide the solar industry with alternatives to the fixed installations that are common today: cells may be printed on plastic rolls that could be unfurled for dozens of uses, or stamped onto fabric for T-shirts or other clothes that collect energy while worn.

The researcher, John A. Rogers, a professor of materials science and engineering at the University of Illinois, Urbana-Champaign, and his team use a standard printing technique to create solar cells that are a tenth the thickness of conventional semiconductor cells, or even thinner. The cells are so flexible that dense arrays of them can be rolled tightly around a pencil. The technology has been licensed to Semprius, a semiconductor company in Durham, N.C., that expects to begin a pilot project making solar modules in about a year. Dr. Rogers’s approach offers a unique strategy for making highly efficient, flexible solar cells for large-scale production, said Ali Javey, an electrical engineer and assistant professor at the University of California, Berkeley, who co-wrote a review of the work for the journal Nature Materials

Traditional silicon solar cells are rigid, heavy and opaque, but they dominate the technology because they are very reliable and efficient, he said, and because silicon is abundant. Still, the brittleness of silicon limits its uses. Dr. Rogers “has figured out how to grab thin layers of silicon or other inorganics, and put them on whatever substrates you want,” Dr. Javey said.

Dr. Rogers’s work is an extension of techniques that he and his collaborators have developed for making flexible electronics over the past five years. The thin solar cells are first fabricated on semiconductor wafers using standard lithographic techniques and then transferred by a soft rubber stamp onto another material, Dr. Rogers said.

The sticky surface of the stamp “picks up the cells,” he said, “and now your stamp is inked with these silicon cells. Then we use the stamp to print them on, for instance, a sheet of plastic.”

George M. Whitesides, a renowned chemist and professor in the department of chemistry and chemical biology at Harvard University, said that Dr. Rogers’s research took advantage of years of progress in silicon fabrication, while at the same time overcoming a basic restriction. “Silicon does work well, but it’s always been the limitation that you make silicon devices on hard, rigid, planal surfaces,” Dr. Whitesides said.

Dr. Rogers has retained the technology for creating silicon devices but developed new forms that were previously off-limits because of silicon’s lack of flexibility. “He’s extended an important technology in directions that will certainly open new applications,” Dr. Whitesides said.

And the ability to make the cells semitransparent may lead to novel uses, for example, in tinted window coatings that also produce energy, Dr. Javey said. The transparency in the cells can be adjusted by controlling their density by printing sheets with fewer cells to enable more light to come though. “Then you can see through the cells as you could through tinted film,” he said.

At its plant in Durham, N.C., where Semprius is developing technology for solar cell arrays, Joe Carr, the company’s chief executive, said, “We almost can’t keep up with all of the opportunities that have been presented to us.” Semprius is working on photovoltaic modules for potential customers including automotive companies interested in the new cells for car roofs, he said.

Dr. Rogers said he was pleased with the new cells’ flexibility and thinness but said that they offered another even more critical advantage. “That the technology is rollable and transparent is important,” he said. “But cost is the paramount consideration for a lot of solar applications, which have to be low-cost per watt generated.” The technology is producing cells that are often only two microns thick (a micron is one-millionth of a meter). “Thinner allows cheaper,” he said.