Solar cells made from common materials
Solar cells for everyone
Courtesy Dominic
Solar cells produce less than 1/1000 of the Earth's electricity. This is mainly because they are expensive and are made from rare, hard to obtain materials.
An IBM research team, managed by David Mitzi, is working on photovoltaic cells that are made from common materials.
The new solar cells are also cheaper to manufacture, using a “printing” technique that uses a hydrazine solution containing copper and tin with nanoparticles of zinc dispersed within it. The solution is then spin-coated and heat treated in the presence of selenium or sulfur vapor. PhysOrg
9.6% Efficiency
This new material, called kesterite, was 6.8% efficient in 2009. IBM increased the efficiency to 9.8% and is planning to increase the efficiency above 11 per cent, which is equal to or better than the traditional solar cells.
Abstract of published paper: High-Efficiency Solar Cell with Earth-Abundant Liquid-Processed Absorber Advanced Materials
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ICON Univ of MN Solar Decathlon enty: crane lowers a section of roof onto the University of Minnesota's Icon House, which arrived on the Mall Oct. 2. The house arrived several days late because of transport difficulties.
Courtesy Richard King/U.S. Department of Energy
20 Solar houses compete in fourth Solar Decathlon
I hope to one day live in a house that produces more energy than it uses. A competition between 20 such houses is going on right now on the Mall in Washington DC. The Solar Decathlon joins 20 college and university teams in a competition to design, build, and operate the most attractive and energy-efficient solar-powered house. Points awarded in ten categories determine the overall winner. As of today (Mon) we have climbed up to 7th place(click for most recent rankings).
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Lots of ways to learn about solar housing design
I have been excitedly working my way through information as it comes in. You can follow a umn_solar_house Twitter feed and there is an ICON Facebook fan page. The Solar Decathalon landing page allows you to jump to photos, videos, and team websites(not working? Try the site map). The University of Minnesota's ICON landing page branches off into a blog, a virtual tour, and lots of educational pages about design. The media (WCCO News and Washington Post) and bloggers (myself included) will be all over this. I recommend GetEnergySmartNow.com's cheat sheet and their overview of the UMN ICON house. You can also download a 966KB PDF media kit about the Solar Decathlon.
Two cylinder Stirling engine: Alpha type Stirling engine. The expansion cylinder (red) is maintained at a high temperature while the compression cylinder (blue) is cooled. The passage between the two cylinders contains the regenerator.
Courtesy Zephyris Four newly designed solar power collection dishes called SunCatchers™ were unveiled at Sandia's National Solar Thermal Test Facility. The new dishes are the next-generation model of the original SunCatcher system. Designed for high-volume production, ease of maintenance, and cost reductions, the dishes could be in commercial service by 2010. The projects are expected to produce 1,000 MW by the end of 2012. One megawatt powers about 800 homes.
Better and cheaper solar conversion
SunCatcher™ power system
Courtesy Randy Montoya Last year one of the original SunCatchers set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate, toppling the old 1984 record of 29.4.
Source: New SunCatcher™ power system unveiled at National Solar Thermal Test Facility, Sandia News release.
Bohmer's invention, a $5 cardboard box solar oven won the FT Climate Change Challenge, for the most innovative and practical solution to climate change.
Nanotube catalyst: 10,000 X smaller than human hairs
Courtesy St Stev
Solving the carbon dioxide problem
Burning fuel releases carbon dioxide and water vapor. A breakthrough process can reverse this reaction. The carbon dioxide and water vapor can be joined into molecules of methane, ethane, or propane by using sunlight as an energy source. The secret to doing this efficiently requires a particular catalyst with a large surface area.
(A) team (at Pennsylvania State University) found it could enhance the catalytic abilities of titanium dioxide by forming it into nanotubes each around 135 nanometres wide and 40 microns long to increase surface area. Coating the nanotubes with catalytic copper and platinum particles also boosted their activity.
Learn more:
Sun-powered device converts CO2 into fuel New Scientist
Solar slowdown: Solar panel revenues projected to drop 19% in 2009
Courtesy richardmasoner
Global finances hurt solar industry
Suntech Power Holdings Co. Ltd., the world's largest solar module maker, suspended its plan to expand capacity by 40 percent in 2009. Instead, it laid off 10 percent of its 8,000 strong workforce.
Global revenues for photovoltaic solar panels are expected to drop 19 percent in 2009, believed to be the sector's first-ever contraction, as prices fall due to oversupply, research firm iSuppli said last December" Reuters
Say it aint so
My hope is that a change in government incentives will prove to be a game changer.
Additional news, First Solar
First Solar was featured by Investopedia yesterday as a solar company to watch in 2009.
Which forms of energy production should the government be subsidizing more? Nuclear or renewable technologies like wind and solar?
Solar cells that work at night
Solar cells become ineffective when the sun goes down. At night, the earth radiates heat back toward the sky. Scientists at the U.S. Department of Energy's Idaho National Laboratory are working on a device to turn infrared radiation into electricity.
Nanoantennas convert infrared rays into electricity
Billions of nanoantennas printed onto thin, inexpensive sheets will transform heat energy into electricity. The physics behind this conversion is the same as that of a radio antenna. The only difference between radiowaves and infrared light is wavelength. Antennas 1/25 the size of a human hair resonate when bombarded with heat radiation. If the resulting alternating current can be passed through a rectifier (one way valve) the current can charge up batteries. The infrared rays create alternating currents in the nanoantennas that oscillate trillions of times per second.
"Today's rectifiers can't handle such high frequencies. "We need to design nanorectifiers that go with our nanoantennas," says Kotter, noting that a nanoscale rectifier would need to be about 1,000 times smaller than current commercial devices and will require new manufacturing methods. Another possibility is to develop electrical circuitry that might slow down the current to usable frequencies." Eureka Alert
If these technical hurdles can be overcome, nanoantennas have the potential to be a cheaper, more efficient alternative to solar cells. Computer models of nanoantennas predict up to 92% efficiency (compared to solar cells around 20%).
Learn more in this video, "Harvesting the sun's energy with antennas"
MIT breakthrough in electric storage problem
Splitting water to store electricity: A snapshot showing the new, efficient oxygen catalyst in action in Dan Nocera's laboratory at MIT.
Courtesy MIT/NSF
Saving up energy for use at night
Want to be energy independent? Solar and wind energy are great but what do you do when the sun goes down and the wind doesn't blow? Batteries with the needed capacity are very expensive.
Energy can be saved up by breaking water apart into hydrogen and oxygen
Using a surprisingly simple, inexpensive technique, chemists have found a way to pull pure oxygen from water using relatively small amounts of electricity, common chemicals and a room-temperature glass of water. At night that oxygen can be combined with hydrogen (also extracted from water) in a fuel cell to make electricity.
The new process, enabling water to more easily be split, is to use a catalyst consisting of cobalt metal, phosphate and an electrode, placed in water.
"When electricity -- whether from a photovoltaic cell, a wind turbine or any other source -- runs through the electrode, the cobalt and phosphate form a thin film on the electrode, and oxygen gas is produced."
"The new catalyst works at room temperature, in neutral pH water, and it's easy to set up. That's why I know this is going to work. It's so easy to implement," Danial Nocera (MIT news office)
Within ten years
Nocera hopes that within 10 years, homeowners will be able to power their homes in daylight through photovoltaic cells, while using excess solar energy to produce hydrogen and oxygen to power their own household fuel cell. Electric vehicles will also power up from this home system.
Learn more: MIT News
What is the best way to store solar energy?
Solar Two: Heat from the sun is stored in a tower containing molten salt.
Courtesy United States Department of Energy What is a good way to store solar energy for when the sun doesn't shine? Batteries are expensive and wear out. Instead of storing electricity, solar thermal systems store heat. A coffee thermos and a laptop computer’s battery store about the same amount of energy. The thermos costs about $5 and the laptop battery $150.
Molten salt at 1000+ degrees
By reflecting sunlight at a tall "power tower", tens of thousands of gallons of molten salt can be heated to very high temperatures (1000 degrees F). The heated salt is used to boil water into steam, spin a turbine and make electric power. By regulating the release of heat, generators can continue to run on rainy days and during the night.
"This technology has been successfully demonstrated and is ready for commercialization. From 1994 to 1999, the Solar Two project demonstrated the ability of solar molten salt technology to provide long-term, cost effective thermal energy storage for electricity generation."
SolarReserve will build solar thermal electric plants
SolarReserve, a company backed in part by United Technologies, is using funding from a U.S. Department of Energy grant to develop utility-scale solar thermal electric generating plants between 100-600 megawatts of electricity. One megawatt is enough power to supply approximately 1,000 US households. Read more at SolarReserves FAQ webpage.
Sources:
New York Times
SolarReserve website (includes a video)
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