New World Record For Efficiency For Solar Cells; Inexpensive To Manufacture

ScienceDaily (May 17, 2008) — Physicist Bram Hoex and colleagues at Eindhoven University of Technology, together with the Fraunhofer Institute in Germany, have improved the efficiency of an important type of solar cell from 21.9 to 23.2 percent (a relative improvement of 6 per cent). This new world record is being presented on Wednesday May 14 at a major solar energy conference in San Diego.

The efficiency improvement is achieved by the use of an ultra-thin aluminum oxide layer at the front of the cell, and it brings a breakthrough in the use of solar energy a step closer.

An improvement of more than 1 per cent (in absolute terms) may at first glance appear modest, but it can enable solar cell manufacturers to greatly increase the performance of their products. This is because higher efficiency is a very effective way of reducing the cost price of solar energy. The costs of applying the thin layer of aluminum oxide are expected to be relatively low. This will mean a significant reduction in the cost of producing solar electricity.

Ultra-thin

Hoex was able to achieve the increase in efficiency by depositing an ultra-thin layer (approximately 30 nanometer) of aluminum oxide on the front of a crystalline silicon solar cell. This layer has an unprecedented high level of built-in negative charges, through which the -- normally significant -- energy losses at the surface are almost entirely eliminated. Of all sunlight falling on these cells, 23.2 per cent is now converted into electrical energy. This was formerly 21.9 per cent, which means a 6 per cent improvement in relative terms.

Dutch company OTB Solar

Hoex gained his PhD last week at the Applied Physics department of the TU/e with this research project. He was supported in the Plasma & Materials Processing (PMP) research group by professor Richard van de Sanden and associate professor Erwin Kessels. This group specializes in plasma deposition of extremely thin layers. The Dutch company OTB Solar has been a licensee of one of these processes since 2001, which it is using in its solar cell production lines. Numerous solar cell manufacturers around the world use equipment supplied by OTB Solar.

The ultra-thin aluminum oxide layer developed in the PMP group may lead to a technology innovation in the solar cell world. A number of major solar cell manufacturers have already shown interest.

Promising

Solar cells have for years looked like a highly promising way to partly solve the energy problem. The sun rises day after day, and solar cells can conveniently be installed on surfaces with no other useful purpose. Solar energy also offers opportunities for use in developing countries, many of which have high levels of sunshine. Within ten to fifteen years the price of electricity generated by solar cells is expected to be comparable to that of 'conventional' electricity from fossil fuels.

This technology breakthrough now brings the industrial application of this type of high-efficiency solar cell closer.

Part of Hoex's PhD research project was paid for by three Dutch ministries: Economic Affairs; Education, Culture and Science; and Housing, Spatial Planning and the Environment.
Adapted from materials provided by Eindhoven University of Technology.

Hybrid Vehicle Competition: Mississippi State Wins DOE And GM Challenge X 2008 Advanced Vehicle Competition

ScienceDaily (May 21, 2008) — Mississippi State University in Starkville, Miss. is the first place winner of Challenge X, in which 17 university teams from across the U.S. and Canada competed to reengineer a General Motors (GM) Chevrolet Equinox Crossover SUV with advanced powertrain configurations. The winner of the competition achieved high fuel economy and low emissions, all while maintaining driver comfort and vehicle performance.

Department of Energy (DOE), GM and Natural Resources Canada also kicked off EcoCAR: The NeXt Challenge, a competition set to begin in the fall of 2008 that will challenge 17 university teams to re-engineer a Saturn VUE.

Over the past four years, 17 Challenge X university teams followed a real-world vehicle development process to produce advanced vehicle powertrain technologies that increased energy efficiency and reduced environmental impact. Those technologies were then integrated into GM vehicles and powered by a variety of alternative fuels including B20 biodiesel, E85 ethanol, reformulated gasoline, and hydrogen. GM, DOE, and the Canadian government congratulated students from 17 participating universities at a finish line ceremony this morning in Washington, D.C.

Students competed in 12 events over the eight day final competition, ranging from on-road emissions and drivability assessments to vehicle performance and consumer acceptability evaluations. The Mississippi State team designed a through-the-road parallel hybrid electric vehicle with all-wheel drive using a turbocharged direct-injection diesel engine fueled by B20 biodiesel. The vehicle demonstrated a 38 percent increase in energy efficiency over the production vehicle, a 1.6 second better quarter-mile acceleration performance, and a 44 percent reduction in well-to-wheel greenhouse gas emissions.

The second place vehicle, engineered by students at the University of Wisconsin – Madison, is a through-the-road parallel hybrid electric vehicle with a 1.9L diesel engine fueled by B20 biodiesel. Ohio State University was awarded third place for its power-split hybrid electric vehicle with a diesel engine fueled by B20 biodiesel.

In 2004, the first year of the program, the Challenge focused on vehicle simulation, modeling and subsystem development, and testing. In the second and third years, students integrated their advanced powertrains and subsystems into the Chevrolet Equinox. In the fourth year, students focused on consumer acceptability and over-the-road reliability and durability of their advanced propulsion systems with real-world evaluation outside of an official testing environment.

DOE’s Argonne National Laboratory (Argonne) provided competition management, team evaluation and technical and logistical support. The Greenhouse gas, Regulated Emissions, and Energy in Transportation model, developed at Argonne, was used to assess a well-to-wheel analysis of the greenhouse gas impacts of each technology approach the teams selected.

The 17 teams that participated in Challenge X are: Michigan Technological University—Houghton, Mich.; Mississippi State University—Starkville, Miss.; The Ohio State University— Columbus, Ohio; Pennsylvania State University—University Park, Pa.; Rose-Hulman Institute of Technology—Terre Haute, Ind.; San Diego State University—San Diego, Calif.; Texas Tech University—Lubbock, Texas; University of Akron—Akron, Ohio; University of California, Davis — Davis, Calif.; University of Michigan—Ann Arbor, Mich.; University of Tennessee—Knoxville, Tenn.; University of Texas at Austin—Austin, Texas; University of Tulsa—Tulsa, Okla.; University of Waterloo—Waterloo, Ontario Canada; University of Wisconsin-Madison — Madison, Wis.; Virginia Tech—Blacksburg, Va.; and West Virginia University— Morgantown, W.Va.

Students participating in the fall EcoCAR competition will design and build advanced propulsion solutions similar to the vehicle categories utilized by the California Air Resources Board (CARB) zero emissions vehicle (ZEV) regulations. In addition, they will incorporate lightweight materials into the vehicles, improve aerodynamics and utilize clean alternative fuels such as ethanol, biodiesel and hydrogen. Funding for EcoCar in FY 2009 and beyond is subject to annual appropriations.

The following teams have been selected to compete in the EcoCAR competition: Embry-Riddle Aeronautical University—Daytona Beach, Fla.; Georgia Tech —Atlanta, Ga.; Howard University —Washington, D.C.; Michigan Technological University — Houghton, Mich.; Mississippi State University — Starkville, Miss.; Missouri University of Science and Technology — Rolla, Miss.; North Carolina State University — Raleigh, N.C.; Ohio State University — Columbus, Ohio; Ontario Institute of Technology — Oshawa, Ontario, Canada; Pennsylvania State University — University Park, Pa.; Rose-Hulman Institute of Technology — Terre Haute, Ind.; Texas Tech University — Lubbock, Texas; University of Victoria Victoria, British Columbia, Canada; University of Waterloo — Waterloo, Ontario, Canada; University of Wisconsin, Madison —Madison, Wis.; Virginia Tech —Blacksburg, Va.; and, West Virginia University —Morgantown, W. Va..
Adapted from materials provided by US Department of Energy.