(this was mailed to me by a friend)
A small disc could be the solution for the efficient and cheap storage of the sun’s energy. A Utah-based company has found a new way to store solar energy – in a small ceramic disk which can store more power for less. Researchers at Ceramatec have created the disk, which can hold up to 20-kilowatt hours, enough to power an entire house for a large portion of the day.
The new battery runs on sodium-sulfur — a composition that typically operates at greater than 600°F. “Sodium-sulfur is more energetic than lead-acid, so if you can somehow get it to a lower temperature, it would be valuable for residential use”, Ralph Brodd, an independent energy conversion consultant, says.
Ceramatec’s new battery runs at less than 200°F. The secret is a thin ceramic membrane that is sandwiched between the sodium and sulfur. Only positive sodium ions can pass through, leaving electrons to create a useful electrical current.
Ceramatec says that batteries will be ready for market testing in 2011, and will sell for about $2000. The disk has not yet been manufactured for residential use, but the creators have spoken optimistically about the possibility.
The convergence of two key technologies — solar power and deep-storage batteries — has profound implications for oil-strapped the US.
“These batteries switch the whole dialogue to renewables,” said Daniel Nocera, professor of energy at the Massachusetts Institute of Technology who sits on Ceramatec’s advisory board. “They will turn us away from dumb technology, circa 1900 — a 110-year-old approach — and turn us forward.”
Wednesday, January 6, 2010
Research on Plastics that Conduct Electricity Receives Funds
Rhett Smith, a Clemson chemistry assistant professor, has been funded by the National Science Foundation CAREER Award to peruse his research regarding the new plastic material that can conduct electricity. The
plastic material is said have enormous uses in a variety of applications like in thin, lightweight and flexible plastic electronic devices that include ultrathin, flexible television displays, computer screens and many other portable electronic devices.
However, the most important aspect of this research aims at utilizing this material to develop thin-film solar cells. There is no need to explain how these thin-film solar cells will contribute to the ongoing efforts to harness renewable energy from the sun. This special material is capable of absorbing and emitting different colors and
therefore is ideal for the production of thin-film solar cells. The total amount of funding, that is $598,000, will assist Rhett to make further advancements in his studies of synthesis and applications of organic and inorganic materials for plastic electronic technologies.
----
Transparent conductors
plastic material is said have enormous uses in a variety of applications like in thin, lightweight and flexible plastic electronic devices that include ultrathin, flexible television displays, computer screens and many other portable electronic devices.
However, the most important aspect of this research aims at utilizing this material to develop thin-film solar cells. There is no need to explain how these thin-film solar cells will contribute to the ongoing efforts to harness renewable energy from the sun. This special material is capable of absorbing and emitting different colors and
therefore is ideal for the production of thin-film solar cells. The total amount of funding, that is $598,000, will assist Rhett to make further advancements in his studies of synthesis and applications of organic and inorganic materials for plastic electronic technologies.
----
Transparent conductors
- Indium tin oxide (ITO)
- pedot (conductive plastic)
- aluminum doped zinc ozide
- stannous chloride - http://www.teralab.co.uk/Experiments/Conductive_Glass/Conductive_Glass_Page1.htm
Super Efficient Next-Generation Solar Cells From Nanotubes
From Technology Review
Carbon nanotube photovoltaics can wring twice the charge from light.
Today’s solar cells lose much of the energy in light to heat. Now researchers at Cornell University have made a photovoltaic cell out of a single carbon nanotube that can take advantage of more of the energy in light than conventional photovoltaics. The tiny carbon tubes might eventually be used to make more-efficient next-generation solar cells.
“The main limiting factor in a solar cell is that when you absorb a high-energy photon, you lose energy to heat, and there’s no way to recover it,” says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory in Golden, CO. Loss of energy to heat limits the efficiency of the best solar cells to about 33 percent. “The material that can convert at a much higher efficiency will be a
game-changer,” says Beard.
Researchers led by Paul McEuen, professor of physics at Cornell, began by putting a single nanotube in a circuit and giving it three electrical contacts called gates, one at each end and one underneath. They used the gates to apply a voltage across the nanotube, then illuminated it with light. When a photon hits the nanotube, it
transfers some of its energy to an electron, which can then flow through the circuit off the nanotube. This one-photon, one-electron process is what normally happens in a solar cell. What’s unusual about the nanotube cell, says McEuen, is what happens when you put in what he calls “a big photon” — a photon whose energy is twice as big as the energy normally required to get an electron off the cell. In
conventional cells, this is the energy that’s lost as heat. In the nanotube device, it kicks a second electron into the circuit. The work was described last week in the journal Science.
There’s evidence that another class of nanomaterials called quantum dots can also convert the energy of one photon into more than one electron. However, making operational quantum-dot cells that can do this has proved a major hurdle, says Beard, whose lab, led by Arthur Nozik, is working on the problem. One of the challenges with quantum-dot solar is that it’s very difficult to get the freed electrons to leave the quantum dot and enter an external circuit. “The system is teasing you; you can’t get those charge carriers out, so what’s the point?” says Ji Ung Lee, professor of nanoscale engineering at the State University of New York in Albany. “McEuen’s group has shown this in a system where you can get the extra carriers out.”
McEuen cautions that his work on carbon nanotube photovoltaics is fundamental. “We’ve made the world’s smallest solar cell, and that’s not necessarily a good thing,” he says. To take advantage of the nanotubes’ superefficiency, researchers will first have to develop methods for making large arrays of the diodes. “We’re not at a point where we can scale up carbon nanotubes, but that should be the ultimate goal,” says Lee, who developed the first nanotube diodes while a researcher at General Electric.
It’s not clear why the nanotube photovoltaic cell offers this two-for-one energy conversion. “It’s mysterious to us,” says McEuen. However, the most likely reason is that while conventional solar materials have only one energy level for electrons to move through, carbon nanotubes have several. And two of them just happen to be very well matched: one of the energy levels, or bandgaps, is twice as high as the other. “We may have gotten lucky, and it has very little to do with the fact that it’s a carbon nanotube,” says McEuen. This means,
McEuen hopes, that even if it proves too challenging to make arrays of nanotube solar cells, materials scientists can look for pairs of materials that have these kinds of matched bandgaps, and layer them to
make solar cells that do with two materials what the single nanotube cells can do. “Maybe the answer won’t be in nanotubes, but in another pair of materials,” McEuen says.
Carbon nanotube photovoltaics can wring twice the charge from light.
Today’s solar cells lose much of the energy in light to heat. Now researchers at Cornell University have made a photovoltaic cell out of a single carbon nanotube that can take advantage of more of the energy in light than conventional photovoltaics. The tiny carbon tubes might eventually be used to make more-efficient next-generation solar cells.
“The main limiting factor in a solar cell is that when you absorb a high-energy photon, you lose energy to heat, and there’s no way to recover it,” says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory in Golden, CO. Loss of energy to heat limits the efficiency of the best solar cells to about 33 percent. “The material that can convert at a much higher efficiency will be a
game-changer,” says Beard.
Researchers led by Paul McEuen, professor of physics at Cornell, began by putting a single nanotube in a circuit and giving it three electrical contacts called gates, one at each end and one underneath. They used the gates to apply a voltage across the nanotube, then illuminated it with light. When a photon hits the nanotube, it
transfers some of its energy to an electron, which can then flow through the circuit off the nanotube. This one-photon, one-electron process is what normally happens in a solar cell. What’s unusual about the nanotube cell, says McEuen, is what happens when you put in what he calls “a big photon” — a photon whose energy is twice as big as the energy normally required to get an electron off the cell. In
conventional cells, this is the energy that’s lost as heat. In the nanotube device, it kicks a second electron into the circuit. The work was described last week in the journal Science.
There’s evidence that another class of nanomaterials called quantum dots can also convert the energy of one photon into more than one electron. However, making operational quantum-dot cells that can do this has proved a major hurdle, says Beard, whose lab, led by Arthur Nozik, is working on the problem. One of the challenges with quantum-dot solar is that it’s very difficult to get the freed electrons to leave the quantum dot and enter an external circuit. “The system is teasing you; you can’t get those charge carriers out, so what’s the point?” says Ji Ung Lee, professor of nanoscale engineering at the State University of New York in Albany. “McEuen’s group has shown this in a system where you can get the extra carriers out.”
McEuen cautions that his work on carbon nanotube photovoltaics is fundamental. “We’ve made the world’s smallest solar cell, and that’s not necessarily a good thing,” he says. To take advantage of the nanotubes’ superefficiency, researchers will first have to develop methods for making large arrays of the diodes. “We’re not at a point where we can scale up carbon nanotubes, but that should be the ultimate goal,” says Lee, who developed the first nanotube diodes while a researcher at General Electric.
It’s not clear why the nanotube photovoltaic cell offers this two-for-one energy conversion. “It’s mysterious to us,” says McEuen. However, the most likely reason is that while conventional solar materials have only one energy level for electrons to move through, carbon nanotubes have several. And two of them just happen to be very well matched: one of the energy levels, or bandgaps, is twice as high as the other. “We may have gotten lucky, and it has very little to do with the fact that it’s a carbon nanotube,” says McEuen. This means,
McEuen hopes, that even if it proves too challenging to make arrays of nanotube solar cells, materials scientists can look for pairs of materials that have these kinds of matched bandgaps, and layer them to
make solar cells that do with two materials what the single nanotube cells can do. “Maybe the answer won’t be in nanotubes, but in another pair of materials,” McEuen says.
Tuesday, January 5, 2010
Genetic Algorithms to optimize solar power.
Bill Gross, the founder of Idealab, talks about his life as an inventor, starting with his high-school company selling solar energy plans and kits. Learn here about a groundbreaking system for solar cells -- and some questions we haven't yet solved.
Monday, January 4, 2010
Europe unites to build renewable energy 'supergrid'
Sun, wind and wave-powered: Europe unites to build renewable energy 'supergrid'
http://www.guardian.co.uk/environment/2010/jan/03/european-unites-renewable-energy-supergrid
http://www.guardian.co.uk/environment/2010/jan/03/european-unites-renewable-energy-supergrid
Subscribe to:
Posts (Atom)
