Amazing Science

Transparent solar panels -- think about it for a moment: Sheets of glass or transparent plastic films that also generate electricity.

 

The concept of transparent solar panels isn’t new, of course, but it now looks like they’re finally finding their way to market: Ubiquitous Energy, a startup that was spun off from MIT last year, is developing a technology and patent portfolio and hopes to bring affordable transparent solar panels to market soon.

 

At this point, you might be wondering how transparent solar cells actually work — after all, if it’s transparent, how can it absorb light energy? The simple answer is that light energy comes in many frequencies (colors), but as far as we humans are concerned, it is only the visible wavelengths — from blue, through green and yellow, to red — that really matter. The Sun, however, pumps out a huge amount of infrared light, and some ultraviolet light — both of which are invisible to the human eye, but which can also generate large amounts of electricity if captured by a solar cell.

 

The trick, then, is creating a solar cell that only absorbs IR and UV radiation, while letting visible light pass straight through. According to Technology Review, Ubiquitous Energy’s transparent solar cell is built up from a series of organic layers on glass or a flexible film. We don’t know the exact nature of the organic materials being used, but other organic solar cells generally use organic polymers that might’ve had their molecular makeup altered to absorb specific wavelengths of light. There are other ways of building transparent solar cells, though: As we reported last year, researchers at UCLA and UC Santa Barbara made a flexible, high-efficiency cell from a mesh of transparent, photovoltaic silver nanowires.

Say goodbye to the grass. The scramble for biofuels is rapidly killing off unique grasslands and pastures in the central US.

 

Christopher Wright and Michael Wimberly of South Dakota State University in Brookings analysed satellite images of five states in the western corn belt. They found that 530,000 hectares of grassland disappeared under blankets of maize and soya beans between 2006 and 2011. The rate was fastest in South Dakota and Iowa, with as much as 5 per cent of pasture becoming cropland each year.

 

The trend is being driven by rising demand for the crops, partly through incentives to use them as fuels instead of food. The switch from meadows to crops is causing a crash in populations of ground-nesting birds. One of the US's most important breeding grounds for wildfowl, an area called the Prairie Pothole Region, is also at risk, with South Dakota's crop fields now within 100 metres of the wetlands. "Half of North American ducks breed here," says Wright.

 

Bill Henwood of the Temperate Grasslands Conservation Initiative in Vancouver, Canada, says the results are distressing. "Exchanging real environmental impacts for the dubious benefits of biofuels is counterproductive," he says. "Last year's record drought in the corn belt all but wiped out the crops anyway."

 

More info: http://tinyurl.com/au236dr

Research conducted at Princeton and Rutgers Universities offers hope of synthetic catalysts that could produce hydrogen from water more efficiently.

 

Hydrogen is often hailed as a promising environmentally-friendly fuel source, but it is also relatively expensive to produce. However, new research conducted at Princeton University and Rutgers University poses the opportunity to produce hydrogen from water at a lower cost and more efficiently than previously thought possible.

 

The research, led by Princeton chemistry professor Annabella Selloni, takes its inspiration from nature – or more specifically, a bacteria that produces hydrogen from water by using enzymes known as di-iron hydro­ge­nases. Selloni and her fellow scientists made use of a computer model to work out how they could incorporate this function of the enzymes into practical synthetic catalysts, in order to enable humans to produce hydrogen from water.

 

In a paper published in the Proceedings of the National Academy of Sciences of the United States of America, Selloni and her co-authors detail how they made changes to existing water-to-hydrogen catalysts, which are often blighted by a susceptibility to oxygen poisoning. While aiming to improve the stability of the structure in water, the team happily fell upon a catalyst which also appears to be tolerant to oxygen, and without sacrificing efficiency.

 

The new artificial catalyst could be produced from abundant and inexpensive components like iron, offering a potentially cheap method of producing hydrogen.

 

The next step for Selloni and her team is to move the research beyond computer models into the real world, and to this end, they hope to eventually produce a working catalyst which produces vast quantities of inexpensive hydrogen for use as a fuel source.

 

The sun's energy is virtually limitless, but harnessing its electricity with today's single-crystal silicon solar cells is extremely expensive—10 times pricier than coal, according to some estimates. Organic solar cells—polymer solar cells that use organic materials to absorb light and convert it into electricity—could be a solution, but current designs suffer because polymers have less-than-optimal electrical properties. Ads by Google San Diego Solar Panels - USA-Made Solar Panels For $0 Down. High Efficiency. Low Cost. Save Now -

 

Researchers at Northwestern University have now developed a new design for organic solar cells that could lead to more efficient, less expensive solar power. Instead of attempting to increase efficiency by altering the thickness of the solar cell's polymer layer—a tactic that has preciously garnered mixed results—the researchers sought to design the geometric pattern of the scattering layer to maximize the amount of time light remained trapped within the cell. Using a mathematical search algorithm based on natural evolution, the researchers pinpointed a specific geometrical pattern that is optimal for capturing and holding light in thin-cell organic solar cells. The resulting design exhibited a three-fold increase over the Yablonovitch Limit, a thermodynamic limit developed in the 1980s that statistically describes how long a photon can be trapped in a semiconductor.

U.S. Naval Research Laboratory scientists in the Electronics Technology and Science Division, in collaboration with the Imperial College London and MicroLink Devices, Inc., Niles, Ill., have proposed a novel triple-junction solar cell with the potential to break the 50 percent conversion efficiency barrier, which is the current goal in multi-junction photovoltaic development.

 

“This research has produced a novel, realistically achievable, lattice-matched, multi-junction solar cell design with the potential to break the 50 percent power conversion efficiency mark under concentrated illumination,” said Robert Walters, Ph.D., NRL research physicist. “At present, the world record triple-junction solar cell efficiency is 44 percent under concentration and it is generally accepted that a major technology breakthrough will be required for the efficiency of these cells to increase much further.”

In multi-junction (MJ) solar cells, each junction is ‘tuned’ to different wavelength bands in the solar spectrum to increase efficiency. High bandgap semiconductor material is used to absorb the short wavelength radiation with longer wavelength parts transmitted to subsequent semiconductors. In theory, an infinite-junction cell could obtain a maximum power conversion percentage of nearly 87 percent.

By exploring novel semiconductor materials and applying band structure engineering, via strain-balanced quantum wells, the NRL research team has produced a design for a MJ solar cell that can achieve direct band gaps from 0.7 to 1.8 electron volts (eV) with materials that are all lattice-matched to an indium phosphide (InP) substrate. “Having all lattice-matched materials with this wide range of band gaps is the key to breaking the current world record” adds Walters. “It is well known that materials lattice-matched to InP can achieve band gaps of about 1.4 eV and below, but no ternary alloy semiconductors exist with a higher direct band-gap.”

Chemists at the University of California, Davis, have engineered blue-green algae to grow chemical precursors for fuels and plastics — the first step in replacing fossil fuels as raw materials for the chemical industry.

Biological reactions are good at forming carbon-carbon bonds, using carbon dioxide as a raw material for reactions powered by sunlight. It’s called photosynthesis, and cyanobacteria, also known as “blue-green algae,” have been doing it for more than 3 billion years.

 

Using cyanobacteria to grow chemicals has other advantages: they do not compete with food needs, like corn’s role in the creation of ethanol.

The challenge is to get the cyanobacteria to make significant amounts of chemicals that can be readily converted to chemical feedstocks. With support from Japanese chemical manufacturer Asahi Kasei Corp., Atsumi’s lab at UC Davis has been working on introducing new chemical pathways into the cyanobacteria.

 

The researchers identified enzymes from online databases that carried out the reactions they were looking for, and then introduced the DNA for these enzymes into the cells. Working a step at a time, they built up a three-step pathway that allows the cyanobacteria to convert carbon dioxide into 2,3 butanediol, a chemical that can be used to make paint, solvents, plastics and fuels.

 

Because enzymes may work differently in different organisms, it is nearly impossible to predict how well the pathway will work before testing it in an experiment, Atsumi said. After three weeks growth, the cyanobacteria yielded 2.4 grams of 2,3 butanediol per liter of growth medium — the highest productivity yet achieved for chemicals grown by cyanobacteria and with potential for commercial development, Atsumi said.

 

Atsumi hopes to tune the system to increase productivity further and experiment with other products, while corporate partners explore scaling up the technology.

The first flexible, fiber-optic solar cell that can be woven into clothes. An international team of engineers, physicists, and chemists have created the first fiber-optic solar cell. These fibers are thinner than human hair, flexible, and yet they produce electricity, just like a normal solar cell. 

 

The research opens the door to the possibility of weaving together solar-cell silicon wires to create flexible, curved or twisted solar fabrics. The findings by an international team of chemists, physicists and engineers, led by John Badding, a professor of chemistry at Penn State, will be posted by the journal Advanced Materials in an early online edition today (Dec. 6) and will be published on a future date in the journal's print edition.

 

The team's new findings build on earlier work addressing the challenge of merging optical fibers with electronic chips -- silicon-based integrated circuits that serve as the building blocks for most semiconductor electronic devices such as solar cells, computers and cellphones. Rather than merge a flat chip with a round optical fiber, the team found a way to build a new kind of optical fiber -- which is thinner than the width of a human hair -- with its own integrated electronic component, thereby bypassing the need to integrate fiber-optics with chips. To do this, they used high-pressure chemistry techniques to deposit semiconducting materials directly, layer by layer, into tiny holes in optical fibers.

 

Now, in their new research, the team members have used the same high-pressure chemistry techniques to make a fiber out of crystalline silicon semiconductor materials that can function as a solar cell -- a photovoltaic device that can generate electrical power by converting solar radiation into direct-current electricity. "Our goal is to extend high-performance electronic and solar-cell function to longer lengths and to more flexible forms. We already have made meters-long fibers but, in principle, our team's new method could be used to create bendable silicon solar-cell fibers of over 10 meters in length," Badding said. "Long, fiber-based solar cells give us the potential to do something we couldn't really do before: We can take the silicon fibers and weave them together into a fabric with a wide range of applications such as power generation, battery charging, chemical sensing and biomedical devices."

 

Badding explained that one of the major limitations of portable electronics such as smartphones and iPads is short battery life. Solar-boosted batteries could help solve this problem. "A solar cell is usually made from a glass or plastic substrate onto which hydrogenated amorphous silicon has been grown," Badding explained. "Such a solar cell is created using an expensive piece of equipment called a PECVD (plasma-enhanced chemical vapor deposition) reactor and the end result is something flat with little flexibility. But woven, fiber-based solar cells would be lightweight, flexible configurations that are portable, foldable and even wearable." This material could then be connected to electronic devices to power them and charge their batteries. "The military especially is interested in designing wearable power sources for soldiers in the field," Badding added.

 

The team members believe that another advantage of flexibility in solar-cell materials is the possibility of collecting light energy at various angles. "A typical solar cell has only one flat surface," Badding said. "But a flexible, curved solar-cell fabric would not be as dependent upon where the light is coming from or where the sun is in the horizon and the time of day." 

Researchers at The Ohio State University (OSU) have successfully completed more than 200 hours of continuous operation of their patented Coal-Direct Chemical Looping (CDCL) technology - a one-step process to produce both electric power and high-purity carbon dioxide (CO2). The test, led by OSU Professor Liang-Shih Fan, represents the longest integrated operation of chemical looping technology anywhere in the world to date.

 

The test was conducted at OSU’s 25 kilowatt thermal (kWt) CDCL combustion sub-pilot unit under the auspices of DOE’s Carbon Capture Program, which is developing innovative environmental control technologies to foster the use of the nation’s vast coal reserves. Managed by the Office of Fossil Energy’s National Energy Technology Laboratory, the program’s specific goal is to develop CO2 capture and compression technologies that can reduce the capital cost and energy penalty of CO2 capture by more than half—equivalent to CO2 capture at less than $40 per metric ton—when integrated into a new or existing coal fired power plant. The successful test moves chemical-looping a step closer to full scale.

 

Chemical looping is an advanced technology that offers several advantages over traditional combustion. In a chemical-looping system, a metal oxide, such as an iron oxide, provides the oxygen for combustion. The metal oxide releases its oxygen in a fuel reactor with a reducing atmosphere, and the oxygen reacts with the fuel. The reduced metal cycles back to an oxidation chamber where the metal oxide is regenerated by contact with air. The metal oxide is then reintroduced into the fuel reactor, thus completing the loop. Since CO2 separation occurs simultaneously with coal conversion, chemical looping offers a low-cost scheme for carbon capture. The process can produce power, synthesis gas, or hydrogen in addition to high-purity CO2.

 

OSU reports that the CDCL plant’s 200+ hours of operation, using metallurgical coke and subbituminous and lignite coals, shows the robustness of its novel moving-bed design and non-mechanical valve operation. The combination resulted in nearly 100 percent solid fuel conversion and a CO2 stream more than 99 percent pure, making it applicable to CO2 enhanced oil recovery operations.

 

The OSU project is expected to benefit the DOE Carbon Capture Program by identifying oxygen carriers and a chemical looping process having the potential to control multiple pollutants, including sulfur dioxide (SO2) and nitrogen oxides (NOx), along with CO2. OSU research aims to identify potential barriers and optimize the CDCL technology and provide realistic data for future technological and economic analysis.

Solar cells made using a process like spray painting have been developed by a research collaboration between scientists at the University of Sheffield.The method could potentially reduce the cost of solar cells significantly meaning the technology could be provided to people in developing countries and perhaps one day be used on glass in buildings or car roofs.

Experts from the University of Sheffield’s Department of Physics and Astronomy and the University of Cambridge have created a method of spray-coating a photovoltaic active layer by an air based process – similar to spraying regular paint from a can – to develop a cheaper technique which can be mass produced.

 

Professor David Lidzey from the University of Sheffield said “Spray coating is currently used to apply paint to cars and in graphic printing. We have shown that it can also be used to make solar cells using specially designed plastic semiconductors. Maybe in the future surfaces on buildings and even car roofs will routinely generate electricity with these materials.

 

“We found that the performance of our spray coated solar cells is the same as cells made with more traditional research methods, but which are impossible to scale in manufacturing. We now do most of our research using spray coating.

 

“The goal is to reduce the amount of energy and money required to make a solar cell. This means that we need solar cell materials that have low embodied energy, but we also need manufacturing processes that are efficient, reliable and consume less energy.”

 

Most solar cells are manufactured using special energy intensive tools and using materials like silicon that themselves contain large amounts of embodied energy.

 

Plastic, by comparison, requires much less energy to make. By spray-coating a plastic layer in air the team hope the overall energy used to make a solar cell can be significantly reduced.

A new form of clean coal technology reached an important milestone recently, with the successful operation of a research-scale combustion system at Ohio State University. The technology is now ready for testing at a larger scale.

For 203 continuous hours, the Ohio State combustion unit produced heat from coal while capturing 99 percent of the carbon dioxide produced in the reaction.

 

Liang-Shih Fan

Liang-Shih Fan, professor of chemical and biomolecular engineering and director of Ohio State’s Clean Coal Research Laboratory,pioneered the technology called Coal-Direct Chemical Looping (CDCL), which chemically harnesses coal’s energy and efficiently contains the carbon dioxide produced before it can be released into the atmosphere.

 

“In the simplest sense, combustion is a chemical reaction that consumes oxygen and produces heat,” Fan said. “Unfortunately, it also produces carbon dioxide, which is difficult to capture and bad for the environment. So we found a way to release the heat without burning. We carefully control the chemical reaction so that the coal never burns—it is consumed chemically, and the carbon dioxide is entirely contained inside the reactor.”

There is enough energy for people to reap from the wind to meet all of the world's power demands without radically altering the planet's climate, according to two independent teams of scientists.

 

Wind power is often touted as environmentally friendly, generating no pollutants. It is an increasingly popular source of renewable energy, with the United States aiming to produce 20 percent of its electricity by wind power by 2030. Still, there have been questions as to how much energy wind power can supply the world, and how green it actually is, given how it pulls energy from the atmosphere.

 

To learn more, climate scientist Katherine Marvel at Lawrence Livermore National Laboratory, in Calif., and her colleagues developed a global climate model that analyzed how wind turbines would drag on the atmosphere to harvest energy from winds at the planet's surface and higher altitudes. Historically, people have built wind turbines on the ground and in the ocean, but research suggests kite-borne turbines could generate more power from steadier, faster high-altitude winds.

 

Adding wind turbines of any kind slows winds, and Marvel and her colleagues found that adding more than a certain amount of turbines would no longer generate more electricity. Still, their simulations suggest that at least 400 terawatts -- or 400 trillion watts of power -- could be generated from surface winds, and more than 1,800 terawatts could be extracted from winds throughout the atmosphere. In comparison, people globally currently use about 18 terawatts of power.

 

Simulating a century's worth of amped-up wind-energy production suggests that harvesting maximum power from these winds would have dramatic long-term effects on the climate, triggering major shifts in atmospheric circulation.

 

Researchers from the University of Oslo have used a bunch of “wonderful tricks” to produce silicon solar cells that are twenty times thinner than commercial solar cells. This breakthrough means that solar cells can be produced using 95% less silicon, reducing production costs considerably — both increasing profits (which are almost nonexistent at the moment), and reducing the cost of solar power installations.

 

Standard, commercial photovoltaic solar cells are fashioned out of 200-micrometer-thick (0.2mm) wafers of silicon, which are sliced from a large block of silicon. This equates to around five grams of silicon per watt of solar power, and also a lot of wastage — roughly half of the silicon block is turned into sawdust by the slicing process. With solar cells approaching 50 cents per watt (down from a few dollars per watt a few years ago), something needs to change.

 

Reducing the thickness of solar cells obviously makes a lot of sense from a commercial point of view, but it introduces another issue: As the wafer gets thinner, more light passes straight through the silicon, dramatically reducing the amount of electricity produced by the photovoltaic effect. This is due to wavelengths: Blue light, which has a short wavelength (450nm), can be captured by a very thin wafer of silicon — but red light, with a longer wavelength (750nm), can only be captured by thicker slabs of silicon. This is part of the reason that current solar cells use silicon wafers that are around 200 micrometers — and also why they’re mirrored, which doubles the effective thickness, allowing them to capture more of the visible spectrum.

Business cards, cellphones and windows could all get a little boost from a sticky new invention. However, fabrication of thin-film solar cells (TFSCs) on substrates other than Si and glass has been challenging because these nonconventional substrates are not suitable for the current TFSC fabrication processes. Researchers have now created thin, flexible solar cells that can stick to paper, plastic, glass and many other materials, just by using double-sided tape.

 

"Now you can put them on helmets, cellphones, convex windows, portable electronic devices, curved roofs, clothing — virtually anything," Xiaolin Zheng, a mechanical engineer at Stanford University who led the development of the new solar cells, said in a statement.

 

The cells are a step toward turning more and more everyday items into either electronics or solar power-harvesting surfaces. Solar cells placed on windows could help a building absorb more solar power than roof installations alone, for example. And a combination of flexible solar panels and electronics could lead to products such as electrified "smart" clothes that control a connected smartphone. With the new peel-and-stick process, the scientists integrated hydrogenated amorphous silicon (a-Si:H) TFSCs on paper, plastics, cell phone and building windows while maintaining the original 7.5% efficiency. The new peel-and-stick process enables further reduction of the cost and weight for TFSCs and endows TFSCs with flexibility and attachability for broader application areas.

 

For the unmanned hydropower plant buried underneath Greenland’s ice cap and a layer of permafrost, the plant’s turbines are 200 meters below the surface and are connected to the meltwater lake that feeds them by a tunnel blasted through the permafrost. The water has to flow constantly so that it doesn’t freeze. The location and the conditions were our biggest challenge.

 

The glaciers and the meltwater lake look majestic, but it’s a harsh environment. The power plant is well within the Arctic circle, 50 kilometers from Ilulissat, which itself is a small community of just 4,500 people. In good weather you can reach the plant by helicopter all year round. In summer you can also travel there by sea, and in winter, when the sea is frozen, by snow-scooter.

 

The power plant is so hard to reach that the plan is not to have to go there at all. The power plant will be manned during the first year, but it’s to be fully automated after that. Hundreds of sensors and seven cameras will record data which an operator will be able to monitor and control through ABB’s control system from the comfort of Ilulissat.

Biologists at UC San Diego have demonstrated for the first time that marine algae can be just as capable as fresh water algae in producing biofuels. Salt ponds in the SF Bay area where the marine algae Dunaliella salina display a bright red color in response to the stress of high salt concentrations.

 

The scientists genetically engineered marine algae to produce five different kinds of industrially important enzymes and say the same process they used could be employed to enhance the yield of petroleum-like compounds from these salt water algae. Their achievement is detailed in a paper published online in the current issue of the scientific journal Algal Research.

 

The ability to genetically transform marine algae into a biofuel crop is important because it expands the kinds of environments in which algae can be conceivably grown for biofuels. Corn, for example, which is used to produce ethanol biofuel, requires prime farmland and lots of fresh water. But the UC San Diego study suggests that algal biofuels can be produced in the ocean or in the brackish water of tidelands or even on agricultural land on which crops can no longer be grown because of high salt content in the soil.

 

"What our research shows is that we can achieve in marine species exactly what we've already done in fresh water species," said Stephen Mayfield, a professor of biology at UC San Diego, who headed the research project. "There are about 10 million acres of land across the United States where crops can no longer be grown that could be used to produce algae for biofuels. Marine species of algae tend to tolerate a range of salt environments, but many fresh water species don't do the reverse. They don't tolerate any salt in the environment."

 

"The algal community has worked on fresh water species of algae for 40 years," added Mayfield, who also directs the San Diego Center for Algae Biotechnology, or SD-CAB, a consortium of research institutions in the region working to make algal biofuels a viable transportation fuel in the future. "We know how to grow them, manipulate them genetically, express recombinant proteins—all of the things required to make biofuels viable. It was always assumed that we could do the same thing in marine species, but there was always some debate in the community as to whether that could really be done."

 

Scaling up the production of biofuels made from algae to meet at least 5 percent – about 10 billion gallons – of U.S. transportation fuel needs would place unsustainable demands on energy, water and nutrients, says a new report from the National Research Council, or NRC. However, these concerns are not a definitive barrier for future production, and innovations that would require research and development could help realize algal biofuels' full potential.