Posts belonging to Category green power

Fuel Cell Electrodes 7 Times More Efficient

A new fabrication technique that produces platinum hollow nanocages with ultra-thin walls could dramatically reduce the amount of the costly metal needed to provide catalytic activity in such applications as fuel cells. The technique uses a solution-based method for producing atomic-scale layers of platinum to create hollow, porous structures that can generate catalytic activity both inside and outside the nanocages. The layers are grown on palladium nanocrystal templates, and then the palladium is etched away to leave behind nanocages approximately 20 nanometers in diameter, with between three and six atom-thin layers of platinum. Use of these nanocage structures in fuel cell electrodes could increase the utilization efficiency of the platinum by a factor of as much as seven, potentially changing the economic viability of the fuel cells.

A transmission electron microscope image shows a typical sample of platinum cubic nanocages

We can get the catalytic activity we need by using only a small fraction of the platinum that had been required before,” said Younan Xia, a professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. Xia also holds joint faculty appointments in the School of Chemistry and Biochemistry and the School of Chemical and Biomolecular Engineering at Georgia Tech. “We have made hollow nanocages of platinum with walls as thin as a few atomic layers because we don’t want to waste any material in the bulk that does not contribute to the catalytic activity.
The research – which also involved researchers at the University of Wisconsin-Madison, Oak Ridge National Laboratory, Arizona State University and Xiamen University in China – was reported in the July 24 issue of the journal Science.


How To Make Solar Energy Conversion More Efficient

When it comes to installing solar cells, labor cost and the cost of the land to house them constitute the bulk of the expense.  The solar cells – made often of silicon or cadmium telluride – rarely cost more than 20 percent of the total costSolar energy could be made cheaper if less land had to be purchased to accommodate solar panels, best achieved if each solar cell could be coaxed to generate more power.

A huge gain in this direction has now been made by a team of chemists at the University of California, Riverside (UCR) that has found an ingenious way to make solar energy conversion more efficientThe researchers report in Nano Letters that by combining inorganic semiconductor nanocrystals with organic molecules, they have succeeded in “upconvertingphotons in the visible and near-infrared regions of the solar spectrum.


Solar-panels UCRChemists at the University of California, Riverside have found an ingenious way to make solar energy conversion more efficient

The infrared region of the solar spectrum passes right through the photovoltaic materials that make up today’s solar cells,” explained Christopher Bardeen, a professor of chemistry. The research was a collaborative effort between him and Ming Lee Tang, an assistant professor of chemistry. “This is energy lost, no matter how good your solar cell.  The hybrid material we have come up with first captures two infrared photons that would normally pass right through a solar cell without being converted to electricity, then adds their energies together to make one higher energy photon.  This upconverted photon is readily absorbed by photovoltaic cells, generating electricity from light that normally would be wasted.”


Solar Panels: Perovskites Better Than Silicon

In the solar power research community, a new class of materials called perovskites is causing quite a buzz, as scientists search for technology that has a better “energy payback time” than the silicon-based solar panels currently dominating the market. Now, a new study by scientists at Northwestern University and the U.S. Department of Energy’s Argonne National Laboratory reports that perovskite modules are better than any commercially available solar technology when products are compared on the basis of energy payback time.

Solar panels are an investment — not only in terms of money, but also energy. It takes energy to mine, process and purify raw materials, and then to manufacture and install the final product. Energy payback time considers the energy that went into creating the product and is a more comprehensive way to compare solar technology than conversion efficiency. The research team reports the energy payback time for solar panel technology made with perovskites could be as quick as two to three months, easily beating silicon-based panels, which typically need about two years to return the energy investment.

perovskite solar panel

People see 11 percent efficiency and assume it’s a better product than something that’s 9 percent efficient,” said Fengqi You, corresponding author on the study and assistant professor of chemical and biological engineering at Northwestern’s McCormick School of Engineering and Applied Science. “But that’s not necessarily true. One needs to take a broad perspective when evaluating solar technology.”

In what’s called a cradle-to-grave life cycle assessment, You and his colleagues traced a product from the mining of its raw materials until its retirement in a landfill. They determined the ecological impacts of making a solar panel and calculated how long it would take to recover the energy invested.

The findings have been published in the journal Energy & Environmental Science .


How To Clean Up Cigarette Smoke

The Korea Institute of Science and Technology (KIST) research team has developed a nano-catalyst for air cleaning in a smoking room that removes 100% of acetaldehyde, the first class carcinogen, which accounts for the largest portion of the gaseous substances present in cigarette smoke.

Air Cleaning DeviceFor the performance evaluation test, the research team made an air cleaning equipment prototype using the nano-catalyst filter. The equipment was installed in an actual smoking room in the size of 30 square meters (with processing capacity of 4 CMM). About 80% of cigarette smoke elements were processed and decomposed to water vapor and carbon dioxide, within 30 minutes, and 100% of them within 1 hour. The test condition is based on the processing capacity which could circulate the air inside the entire 30 square meter smoking room once every 15 mns.

The nano-catalyst filter uses a technology that decomposes elements of cigarette smoke using oxygen radical, which is generated by decomposing ozone in the air on the surface of the manganese-oxide-based nano-catalyst filter. An evaluation test with total volatile organic compounds (TVOC), such as acetaldehyde, nicotine and tar, which account for the largest volume of gaseous materials in cigarette smoke, is conducted to evaluate the performance of the newly-developed catalyst. The results show that the new catalyst decomposes over 98% of the aforementioned harmful substances.


Electric Planes Cross The Channel

Airbus Group  Friday completed its first-ever flight of an electric plane across the English Channel as the European plane maker seeks to spark interest in less polluting aircraft.

E fan

Airbus’s two-seat E-Fan demonstrator plane powered exclusively by lithium-batteries took 36 minutes to fly from Lydd in southern England to Calais, France, on the historic hop. It came soon after the single-seat Solar Impulse 2 flew from Japan to Hawaii in the longest-ever solar-powered flight as part of an around-the-world journey.

Just as cars are moving from burning fossil fuels to battery power, aircraft makers are exploring a similar shift to reduce carbon dioxide emissions. “It’s a big steppingstone,” said Jean Botti, chief technical officer at Airbus.

Private pilot Hugues Duval beat Airbus to the bragging rights of completing the first-ever Channel crossing in an electric plane when he traversed the body of water on Thursday in his single-seat Cri-Cri plane.

Airbus, better known for making airliners seating more than 100 passengers, plans to start delivering two-seat production versions of the E-Fan in 2017 through its VoltAir subsidiary.

A four-seat E-Fan 4.0 could follow 18 months later. It would introduce hybrid technology that could provide a springboard to building regional planes carrying 100 passengers, Mr. Botti said.



Train Of The Future

Hyperloop Transportation Technologies says it’s about to break ground on a full scale test track for it’s revolutionary future travel means, the Hyperloop, which will take passengers through steel tubes at speeds potentially up to 760mph (1223 km/h). For those that dream of the future, even this might have seemed a long way off.



Imagine a capsule filled with people that’s hovering inside the tube. Inside the tube you create a low pressure environment very similar to an airplane that’s at high altitudes. So now the capsule travelling inside the tubes doesn’t encounter as much resistance, and so therefore can travel really fast with very little energy“, says Hyperloop Transportation Technologies CEO, Dirk Ahlborn.

No accidents, environmentally friendly and tickets that cost next to nothing: This was once an idea drawn out by billionaire entrepreneur Elon Musk, but it’s Dirk Ahlborn that’s also trying to make it a reality. Musk’s SpaceX are planning a track and asking others to design the pods that will carry passengers. But Ahlborn and his company Hyperloop Transportation Technologies (HTT) are about to build their own in California.  HTT are about to break ground on the test track next year in Quay Valley. But that, he says, is just the beginning: “So do we need a ticket? Are there other ways of creating revenue? The pylons are just out of concrete – so you can have concrete that cleans the air, you can have gardens in them, you could have bee hives inside those concrete pylons, different energy solutions, so there’s lots of things that we can do to create a new cutting edge technology.”

It’s not just the technology that Ahlborn is pioneering either. He and his team of around 360 people at HTT have been able to push forward so quickly by crowdsourcing talent and labour. That means they could be carrying passengers in just a couple of years. “Quay Valley going to be full scale, we’re going to move around 10 million people a year, it’s going to be opening up in 2018,” says Ahlborn.

That could mean tucking into your starter in Vienna and polishing off your dessert in London. A once distant dream that now looks closer than ever to reality.


Electric Car: Nanogenerator Harvests Power From Rolling Tires

A group of University of Wisconsin-Madison engineers and a collaborator from China have developed a nanogenerator that harvests energy from a car’s rolling tire friction.

An innovative method of reusing energy, the nanogenerator ultimately could provide automobile manufacturers a new way to squeeze greater efficiency out of their vehicles. Xudong Wang, the Harvey D. Spangler fellow and an associate professor of materials science and engineering at UW-Madison, and his PhD student Yanchao Mao have been working on this device for about a year.

The nanogenerator relies on the triboelectric effect to harness energy from the changing electric potential between the pavement and a vehicle’s wheels. The triboelectric effect is the electric charge that results from the contact or rubbing together of two dissimilar objects.

Wang says the nanogenerator provides an excellent way to take advantage of energy that is usually lost due to friction.


The friction between the tire and the ground consumes about 10 percent of a vehicle’s fuel,” he says. “That energy is wasted. So if we can convert that energy, it could give us very good improvement in fuel efficiency.”

The researchers reported their development, which is the first of its kind, in a paper published May 6, 2015, in the journal Nano Energy.


Hydrogen Batteries Power Airliners Galley

Fuel cells hidden inside trolleys used to serve passengers their in-flight drinks could generate enough additional energy to power an airliner’s entire galley, according to German researchers. Passengers on airliners are used to their in-flight snacks coming from the flight attendant’s trolley. In the future, that trolley could provide enough power to cook a plane-load of meals. German researchers have been showcasing their portable fuel cell at the Paris Air show.


What you see here is an energy generation system with a tank, a reformer, a fuel cell and a battery. The fuel cell hybrid system produces enough power for one galley and if I put it in, you can see the galley is now powered by the trolley,” said  Ronny Knepple, head of energy systems at developer Diehl Aerospace. Diehl‘s humble-looking trolley houses a tank filled with liquid propylene glycol which provides the hydrogen – the fuel source for the battery.

“The propylene glycol from the tank is evaporated and here in the reformer at high temperature the hydrogen is extracted from the propylene glycol,” explains Professor Gunther Kolb from Fraunhofer Institute for Chemical Technology (Germany)  and one of the power unit’s designers.
A catalytic converter in the trolley transforms the toxic by-products of the reaction into carbon dioxide and water. And the compact unit is lighter and smaller than conventional energy systems.
We have used here our special plate heat exchanger technology, which allows us to reduce weight and especially the size of the system considerably. In some cases here, we could save 90 percent of the space required by conventional technology,” adds Prof. Kolb. Planes in service for decades are often refurbished with power-hungry new technology in their galleys. Diehl and its collaborators hope their system will provide an independent power source for increased energy demands. The prototype lighting up the galley in Paris could be seen on airliners within 2 years.


Wind Turbines Generate Electricity Without Rotating

A suspension bridge in the United States stretching – and collapsing – in high winds in 1940… …inspires a silent, swaying new-look wind turbine in Spain today. The bladeless turbine generates power from a single conewobbling‘ in the wind. It’s just like an opera singer hitting the high notes and shattering glass, says the developer.


We have all seen how a soprano who sings at a glass, by matching the tone of the voice to the glass, can breaking it. This type of resonance is a great way to transmit energy. What we do is, instead of using sound waves, is use the swirls, the vortices that are generated by a structure with wind“, says David Yanez, who co-founded the Spanish start-up, Vortex Bladeless.
The six-metre windmill, made from fibreglass and carbon fibre, uses those wind vortices to create patterns of movement that can be converted into energy. The magnets at the base of the cone-shaped blade allow its movements to adjust according to the wind speed.

What we have is a mast, which is the top piece, and acts as a blade, it’s constructed from the same material as a conventional generator, and what it does is oscillate transmitting its oscillation to a conventional alternator which by its own oscillation converts the wind’s energy into electric energy.” Vortex says its turbine will cost around 40 percent less than conventional three-bladed windmills, with a smaller carbon footprint and much lower maintenance costs. And it’s much safer for passing birds. Encouraged by the results so far, Vortex is testing a smaller prototype for domestic use in developing countries.
What we are trying to do now is develop a very small energy distribution sample that is less than three metres high and can be set up on the rooftops of homes“, adds David Yanez.

Vortex‘s new turbine could prove a boost for renewable energy after Spain’s financial crisis hit the industry hard. With investment, the start-up hopes generating energy from wind will be a breeze.

How To Boost Battery Performance

Stanford University scientists have created a new carbon material that significantly boosts the performance of energy-storage technologies.
A new ”designer carbon” invented by Stanford scientists significantly improved the power-delivery rate of this supercapacitor

We have developed a ‘designer carbon’ that is both versatile and controllable,” said Zhenan Bao, the senior author of the study and a professor of chemical engineering at Stanford. “Our study shows that this material has exceptional energy-storage capacity, enabling unprecedented performance in lithium-sulfur batteries and supercapacitors.”

According to Bao, the new designer carbon represents a dramatic improvement over conventional activated carbon, an inexpensive material widely used in products ranging from water filters and air deodorizers to energy-storage devices.

A lot of cheap activated carbon is made from coconut shells,” Bao said. “To activate the carbon, manufacturers burn the coconut at high temperatures and then chemically treat it.

The findings are featured on the cover of the journal ACS Central Science.


Barcelona, The Sun And Wind City

Barcelona‘s beach is being lit up with new-look street lights. The six innovative lamp posts are each fitted with two solar panels, a wind turbine and a battery. As a result, the environmentally-friendly lights generate enough energy to run for ten hours overnight. The new product has been designed by the company Eolgreen with the collaboration of a research team from the Universitat Politecnica de Catalunya (UPC).


click on the image to enjoy the video

Compared to a traditional street lighting system, these six street lights that we have set up emit two tonnes less CO2 per year than sodium vapour or mercury vapour bulbs we see in conventional systems,” says Pedro Montes leads research at developers Eolgreen. The company also says its lights are 20 percent cheaper to run than conventional lights because they use LED technology and are independent from the electricity grid. While solar-powered LED street lighting is used elsewhere, Eolgreen‘s system is unique because its graphene turbines turn with even a gentle breeze.

Ramon Bargallo, researcher at the UPC, who helped  design the independently-powered lights adds:  “It was a big challenge as generators often need high speed winds to turn, between 1500 rpm and 3000 rpm. But we needed a generator able to work with only four or five rpm. Also generators are normally more efficient the higher the wind speed and less efficient at low wind speeds, so we had to design it in the opposite way.” Barcelona’s planners aim to roll out the new lighting system across the whole city. It’s part of their drive to achieve energy self-sufficiency in the next 40 years. Eolgreen intends to ramp up production to 700 streetlights by the end of the year. While the sustainable energy developers continue to improve efficiency, they hope their system will soon be brightening streets all over Spain.


Black Silicon Solar Cells Efficiency Jump

Researchers from Aalto University (Finland) together with colleagues from Universitat Politècnica de Catalunya (Spain) have obtained the record-breaking efficiency of 22.1% on nanostructured silicon solar cells as certified by Fraunhofer ISE CalLab. An almost 4% absolute increase to their previous record is achieved by applying a thin passivating film on the nanostructures by Atomic Layer Deposition, and by integrating all metal contacts on the back side of the cell.black_silicon_solar_cell_hele_savin_aalto_university_en

The surface recombination has long been the bottleneck of black silicon solar cells and has so far limited the cell efficiencies to only modest values. The new record cells consists of a thick back-contacted structure that is known to be highly sensitive to the front surface recombination. The certified external quantum efficiency of 96% at 300nm wavelength demonstrates that the increased surface recombination problem no longer exists and for the first time the black silicon is not limiting the final energy conversion efficiency. The energy conversion efficiency is not the only parameter that we should look at, explains Professor Hele Savin from Aalto University, who coordinated the study. Due to the ability of black cells to capture solar radiation from low angles, they generate more electricity already over the duration of one day as compared to the traditional cells.

The results were published online 18.5.2015 in Nature Nanotechnology.