The Solar PowerFlower is a portable concentrated photovoltaic power generator intended for agricultural use.
It was designed by Jason Halpern, co-founder of PowerFlower Solar, who began developing the technology while still a student at the University of Pennsylvania.
Physicists at Boston College have developed a nano-scale solar cell, inspired by the coaxial cable, which offers greater efficiency than any previously designed nanotech thin film solar cell
A limiting factor in making highly efficient thin film sollar cells is the need for the cells to be thick enough to collect a sufficient amount of light, yet thin enough to extract current. The Boston College researchers have found a way to resolve this challenge using a coaxial design for cells constructed with amorphous, rather than crystalline, silicon
The researchers say that the nanocoax cells yield power conversion efficiency in excess of 8 percent, which is higher than any nanostructured thin film solar cell to date.
"Many groups around the world are working on nanowire-type solar cells, most using crystalline semiconductors," said Michael Naughton, a professor of physics at Boston College. "This nanocoax cell architecture, on the other hand, does not require crystalline materials, and therefore offers promise for lower-cost solar power with ultrathin absorbers. With continued optimization, efficiencies beyond anything achieved in conventional planar architectures may be possible, while using smaller quantities of less costly material."
A team led by Professor Benoît Marsan at the Université du Québec à Montréal say that they have solved some of the problems have been hampering the development of efficient and affordable solar cells.
One of the most promising solar cells designs is the dye-sensitized cell, which was designed in the early ’90s based on the principle of photosynthesis. A dye-sensitized solar cell consists of a porous layer of nanoparticles of a white pigment (titanium dioxide) covered with a molecular dye that absorbs sunlight. The pigment-coated titanium dioxide is immersed in an electrolyte solution with a platinum-based catalyst. Sunlight passes through the platinum-based cathode and the electrolyte, and then withdraws electrons from the titanium dioxide anode.
This type of cell has some problems that have prevented its large-scale commercialisation:
Professor Marsan realized that two of the technologies developed for the electrochemical solar cell could also be applied to the dye-sensitized solar cell. Entirely new molecules, created in the laboratory, can be used in a liquid or gel electrolyte which is transparent and non-corrosive - thus improving the cell’s output and stability - and platinum can be replaced by cobalt sulphide, which is far less expensive, more efficient, more stable and more readily available.
Researchers led by Dr Zhong Wang of the Georgia Institute of Technology have developed what they call the world’s first 3-D solar panel system. They claim that their system is cheaper, and up to six times more efficient, than conventional. planar solar cells.
Instead of using traditional solar panels, the system captures sunlight and turns it into electricity within fibre optic cables.
The scientists seeded optical fibres with zinc oxide nanostructures. Those nanostructures were then coated with a dye-sensitized material that converts light into electricity. The electricity is then captured using a liquid electrolyte surrounding the nanostructures.
Only the very tip of the cable needs to be exposed to light, meaning that most of the system can easily be concealed under roofs, in walls or even underground. This not only opens up architectural opportunities for concealing the solar panels but enables them to be protected from envirommental damage, such as from hail.
When any light which is not absorbed and converted into electricity reaches the end of the cable, it bounces back - doubling the chance of absorption. Dr Wang says that the result is up to six times more efficient than standard, planar solar cells with the same surface area.
The 3-D solar cells are cheap to manufacture because their main components are common materials like the fibre optic cables used in telecommunications and zinc oxide which is commonly used as a sunscreen, and because the manufacturing process requires much lower temperatures (about 70°C) than conventional solar cell production.
Sandia National Laboratories scientists have developed tiny "glitter-sized" photovoltaic cells which they say could revolutionize the way solar energy is collected and used.
The solar particles, made of crystalline silicon, are 10 times thinner than conventional 6-inch-by-6-inch cells, yet perform at about the same efficiency. As a result, 100 times less silicon generates same amount of electricity.
The micro-cells are expected eventually to be less expensive and have greater efficiencies than current photovoltaic collectors.
Sandia lead investigator Greg Nielson said “Eventually units could be mass-produced and wrapped around unusual shapes for building-integrated solar tents and maybe even clothing. This would make it possible for hunters, hikers or military personnel in the field to recharge batteries for phones, cameras and other electronic devices as they walk or rest."
Photovoltaic modules made from these microsized cells for rooftops could have intelligent controls, inverters and even storage built in at the chip level. Such an integrated module could greatly simplify the cumbersome design and integration process necessary with current solar cells.
Solar concentrators can be placed directly over each micro-cell to increase the number of photons arriving to be converted into electrons. The small cell size means that cheaper and more efficient short focal length microlens arrays can be used for this purpose.
According to the market research company, The Information Network, the wholesale price of solar panels has dropped from $US4.05 per watt a year ago to $US1.85 today. The company predicts that the price could drop below $US1 per watt next year and be as low as $US0.50 per watt in 2011.
The main reason for the falling price is increased manufacturing capacity in China combined with decreased demand during the global financial downturn.
Not only has Chinese competition directly forced lower pices but European countries have begun scaling back their subsidies because the funds were increasingly going towards imports from China rather than supporting local manufacturers.
The Informatioin Network predicts that as many as half of the more than 200 solar manufacturers in the United States will not be able to survive if prices remain below $US2 per watt.
Entech Solar, a Texas company with solar projects in more than twenty countries, has has completed a preliminary design review and prototype of its next-generation concentrating solar panel, the ThermaVolt II, which combines concentrating photovoltaic and thermal technologies. The company says its product delivers four to five times the amount of energy of traditional photovoltaic systems and costs less to produce.
The ThermaVolt II uses proprietary arched Fresnel lenses to concentrate sunlight about 20 times onto the solar cells, saving about 95% of the relatively expensive silicon cell material.
Normally, this would cause the PV arrays to can get extremely hot. This energy is usually wasted but the ThermaVolt system uses the heat to deliver power and heating from the same unit.
The panels are designed to be picked up and installed by workers in the same fashion as traditional flat-plate PV panels and are made to standard flat-plate dimensions which are easily compatible with existing trackers in the marketplace.
Italy’s Milano Fiera trade fair facility has announced that it will soon be getting the world’s largest solar rooftop solar array.
The photovoltaic system will cover 270,000 square metres of the roof, and carry a peak capacity of 18 megawatts. The system is due for completion next year. Zaragoza, Spain’s General Motor’s factory, currently holds the record for largest rooftop solar plant at 12 megawatts.
The Trade Fair is calling for bids to build the plant at an estimated cost of 70-80 million euros. The winning bidder will pay the Milan fair a rental fee in return for which it will be able to market the power generated. Italy introduced an incentive scheme in 2007 for solar power that guarantees operators up to 0.49 euros per kilowatt hour produced for 20 years.
Better Place has released the video below demonstrating its battery swapping process.
Better Place is planning a network of charging stations and battery swap facilities in Israel, Denmark, Australia and the United States. See this article at Aussie Renewables for more details.
The battery swap demonstration at Yokohama took 1 minute and 13 seconds. Power to recharge the batteries was drawn from photovoltaic panels.
Scientists from the Rensselaer Polytechnic Institute in New York have developed a new design for solar panels which dramatically increases their efficiency
The solar panels have rows of miniature concentrator lenes with concententric grooves which track the sun’s movement and focus it on postage-stamp sized solar cells. Microchannels at the base of the module transfer energy in the form of heat and light to wires contained inside the channels.
Conventional solar systems are about 14 percent efficient. This system has a combined heat and power efficiency of nearly 80 percent.
Anna Dyson, an architectural scientist from the Rensselaer Polytechnic Institute says that "we basically have a system that can sense where the sun is at any time, and then the modules will basically be facing directly perpendicular to the incoming sun rays".
The lenses will be nestled between window panes and all of the pieces will be made of glass. Rows or stacks of these can be incorporated into a building’s facade.This will also lower the lighting needs of buildings, as it will provide usable light inside the building. It could supply as much as 50 percent of the energy needed for a building to operate.
The system is being installed in the Center for Excellence and Environmental Energy Systems in Syracuse, New York and will also be installed in the Fashion Institute of Technology in New York City.
