Posts belonging to Category green power

Electric Car: More Silicon To Enhance Batteries

Silicon – the second most abundant element in the earth’s crust – shows great promise in Li-ion batteries, according to new research from the University of Eastern Finland. By replacing graphite anodes with silicon, it is possible to quadruple anode capacity.

In a climate-neutral society, renewable and emission-free sources of energy, such as wind and solar power, will become increasingly widespread. The supply of energy from these sources, however, is intermittent, and technological solutions are needed to safeguard the availability of energy also when it’s not sunny or windy. Furthermore, the transition to emission-free energy forms in transportation requires specific solutions for energy storage, and lithium-ion batteries are considered to have the best potential.

Researchers from the University of Eastern Finland introduced new technology to Li-ion batteries by replacing graphite used in anodes by silicon. The study analysed the suitability of electrochemically produced nanoporous silicon for Li-ion batteries. It is generally understood that in order for silicon to work in batteries, nanoparticles are required, and this brings its own challenges to the production, price and safety of the material. However, one of the main findings of the study was that particles sized between 10 and 20 micrometres and with the right porosity were in fact the most suitable ones to be used in batteries. The discovery is significant, as micrometre-sized particles are easier and safer to process than nanoparticles. This is also important from the viewpoint of battery material recyclability, among other things.

In our research, we were able to combine the best of nano– and micro-technologies: nano-level functionality combined with micro-level processability, and all this without compromising performance,” Researcher Timo Ikonen from the University of Eastern Finland says. “Small amounts of silicon are already used in Tesla’s batteries to increase their energy density, but it’s very challenging to further increase the amount,” he continues.

Next, researchers will combine silicon with small amounts of carbon nanotubes in order to further enhance the electrical conductivity and mechanical durability of the material.

The findings were published in Scientific Reports .


How To Convert 90% Of Water Into Hydrogen

Researchers from North Carolina State University (NC State) have significantly boosted the efficiency of two techniques, for splitting water to create hydrogen gas and splitting carbon dioxide (CO2) to create carbon monoxide (CO). The products are valuable feedstock for clean energy and chemical manufacturing applications. The water-splitting process successfully converts 90 percent of water into hydrogen gas, while the CO2-splitting process converts more than 98 percent of the CO2 into CO. In addition, the process also uses the resulting oxygen to convert methane into syngas, which is itself a feedstock used to make fuels and other products.

These advances are made possible by materials that we specifically designed to have the desired thermodynamic properties for each process,” says Fanxing Li, an associate professor of chemical and biomolecular engineering at NC State who is corresponding author of two papers on the work. “These properties had not been reported before unless you used rare earth materials.”

For the CO2-splitting process, researchers developed a nanocomposite of strontium ferrite dispersed in a chemically inert matrix of calcium oxide or manganese oxide. As CO2 is run over a packed bed of particles composed of the nanocomposite, the nanocomposite material splits the CO2 and captures one of the oxygen atoms. This reduces the CO2, leaving only CO behind.

Previous CO2 conversion techniques have not been very efficient, converting well below 90 percent of the CO2 into CO,” Li says. “We reached conversion rates as high as 99 percent. “And CO is valuable because it can be used to make a variety of chemical products, including everything from polymers to acetic acid,” Li adds.

Meanwhile, the oxygen captured during the CO2-splitting process is combined with methane and converted into syngas using solar energy.


Three-Wheeled Electric Vehicle

This three-wheeled vehicle is the culmination of 10 years of work For Mark Frohnmayer. It’s the Arcimoto SRK — an all-electric commuter vehicle retailing at a base price of $12,000 — and Frohnmayer hopes his first customers will have them in their driveways by the end of summer.


“I thought, you know, if we can build something that was much closer to the motorcycle in terms of efficiency and fun factor and, you know, footprint on the road but was close to the car in terms of capabilities and enclosable and carries groceries and stable, that we’d have a real product opportunity that the world has been missing for a long time,” says Mark Frohnmayer, Founder and President of Arcimoto SRK.

Frohnmayer built seven generations of prototypes with regular car steering wheels. His breakthrough moment came when he replaced the steering wheel with motorcycle handlebars.

By switching to handlebar steering, we were able to move the passengers into a more upright seating position like you’d have on a city scooter and that let us shorten the vehicle by almost two feet and drop hundreds of pounds — almost 600 pounds — of weight between generations 6 or generation 7 and generation 8 and that moved us way beyond our actual weight target and let us drop the cost to a point where it was actually going to be in the sweet spot that we were aiming for”, explains Frohnmayer.

The SRK can reach 85 mph (137 km/h) and has a range of 70 miles (113 km). It has an equivalent fuel consumption of 230 MPG”, the company says.
Arcimoto has already taken 1,500 reservations and hopes it’s just the beginning. Frohnmayer believes his small cars will soon have a big impact in the fight against climate change – offering commuters a sustainable and eco-friendly option to get to work.


Green Solar Panels And Other Colors

Researchers from AMOLF, the University of Amsterdam (UvA) and the Energy Research Centre of the Netherlands (ECN) have developed a technology to create efficient bright green colored solar panels. Arrays of silicon nanoparticles integrated in the front module glass of a silicon heterojunction solar cell scatter a narrow band of the solar spectrum and create a green appearance for a wide range of angles. The remainder of the solar spectrum is efficiently coupled into the solar cell. The current generated by the solar panel is only  reduced by 10%. The realization of efficient colorful solar panels is an important step for the integration of solar panels into the built environment and landscape.
research has much focused on maximizing the electricity yield obtained from solar panels: nowadays, commercial panels have a maximum conversion efficiency from sunlight into electricity of around 22%. To reach such high efficiency, silicon solar cells have been equipped with a textured surface with an antireflection layer to absorb as much light as possible. This creates a dark blue or black appearance of the solar panels.

To create the colored solar panels the researchers have used the effect of Mie scattering, the resonant backscattering of light with a particular color by nanoparticles. They integrated dense arrays of silicon nanocylinders with a diameter of 100 nm in the top module cover slide of a high-efficiency silicon heterojunction solar cell. Due to the resonant nature of the light scattering effect, only the green part of the spectrum is reflected; the other colors are fully coupled into the solar cell. The current generated by the mini solar panel (0,7 x 0,7 cm2)  is only reduced by 10%. The solar panel appears green over a broad range of angles up to 75 degrees. The nanoparticles are fabricated using soft-imprint lithography, a technique that can readily be scaled up to large-area fabrication.
The light scattering effect due to Mie resonances is easily controllable: by changing the size of the nanoparticles the wavelength of the resonant light scattering can be tuned. Following this principle the researchers are now working to realize solar cells in other colors, and on a combination of different colors to create solar panels with a white appearance. For the large-scale application of solar panels, it is essential that their color can be tailored.

The new design was published online in the journal Applied Physics Letters.


Biodegradable Car

TU/Ecomotive (Netherlands) says ‘Lina‘ is the world’s first car with a fully biocomposite body structure. The 4-seat e-car‘s chassis uses a combination of bio-composite and bio-plastic made from sugarbeet.


It’s made of flax, the outside is made of flax fibres, together with polypropylene. It’s pressed and heated to make flat panels. In the middle you can see polylactic acid, the honeycomb structure of that material, which adds to the strength and weight savings of the sandwich panel. All structural parts of the car are made of this material,” says Yanic Van Riel, TU/Ecomotive.

The biocomposite has a similar strength-weight ratio to fibreglass, making the car light, greatly reducing battery size.

The car weighs only 310 kilograms which is really light for a car. That’s why we only need 30 kilograms of batteries. And on those 30 kilograms of battery packs we can drive around 100 kilometres, which is about four times more efficient than a BMW i3 right now and that’s in real city driving, so braking, stopping, accelerating, not just like the most optimal driving,” explains Yanic Van Riel.

Lina has a top speed of around 50 miles per hour. Electronic features include NFCnearfield communication technology.  “We can open our doors with NFC technology and a car will immediately recognise who is driving it. So if I’m opening it, it will save all the data from me and if someone else opens it, it will save his data. In that way we can use this car for carsharing apps, which other companies are creating. Also we have a hood system which projects the speed and all the information of the car into the front window, so we can see it through the window and still see the road, so it’s more safe,” adds Noud Van De Gevel, TU/Ecomotive.

The team hopes the prototype will soon be declared roadworthy, allowing it to be tested on Eindhoven city streets.


No More Batteries For Cellphones

University of Washington (UW) researchers have invented a cellphone that requires no batteries — a major leap forward in moving beyond chargers, cords and dying phones. Instead, the phone harvests the few microwatts of power it requires from either ambient radio signals or light.

The team also made Skype calls using its battery-free phone, demonstrating that the prototype made of commercial, off-the-shelf components can receive and transmit speech and communicate with a base station.


We’ve built what we believe is the first functioning cellphone that consumes almost zero power,” said co-author Shyam Gollakota, an associate professor in the Paul G. Allen School of Computer Science & Engineering at the UW. “To achieve the really, really low power consumption that you need to run a phone by harvesting energy from the environment, we had to fundamentally rethink how these devices are designed.”

The team of UW computer scientists and electrical engineers eliminated a power-hungry step in most modern cellular transmissionsconverting analog signals that convey sound into digital data that a phone can understand. This process consumes so much energy that it’s been impossible to design a phone that can rely on ambient power sources. Instead, the battery-free cellphone takes advantage of tiny vibrations in a phone’s microphone or speaker that occur when a person is talking into a phone or listening to a call.

An antenna connected to those components converts that motion into changes in standard analog radio signal emitted by a cellular base station. This process essentially encodes speech patterns in reflected radio signals in a way that uses almost no power. To transmit speech, the phone uses vibrations from the device’s microphone to encode speech patterns in the reflected signals. To receive speech, it converts encoded radio signals into sound vibrations that that are picked up by the phone’s speaker. In the prototype device, the user presses a button to switch between these two “transmitting” and “listening” modes.

The new technology is detailed in a paper published July 1 in the Proceedings of the Association for Computing Machinery on Interactive, Mobile, Wearable and Ubiquitous Technologies.


Hyperloop, Train Of The Future, Nearly Hits 200 mph

After announcing “the successful completion of the world’s first full systems Hyperloop test in a vacuum environment” last month, Hyperloop One is now releasing the details of a new test with their actual pod in their vacuum test tube.

They achieved a new top speed of 192 mph (310 km an hour).

Shervin Pishevar, Executive Chairman and Co-founder of Hyperloop One, made the announcement

This is the beginning, and the dawn of a new era of transportation. We’ve reached historic speeds of 310 km an hour, and we’re excited to finally show the world the XP-1 going into the Hyperloop One tube. When you hear the sound of the Hyperloop One, you hear the sound of the future.”

It’s still not on par with the ~700 mph speed that they originally planned the system to enable, but the full-scale 500-meter test track is shorter than the previously announced 1-mile long tube and it is still early in their development process.

They achieved the new top speed on just 300 meters of propulsion ramp, which is impressive, and they increased the speed by 2.7x over last month’s first test. The company disclosed that “all components of the system were successfully tested, including the highly efficient electric motor, advanced controls and power electronics, custom magnetic levitation and guidance, pod suspension and vacuum system.”


By 2025 Renewables Will Power 67 Percent Of South Australia

Declining renewables and energy storage costs will increasingly squeeze out gas-fired generation in South Australia as early as 2025, a joint research report conducted by Wood Mackenzie and GTM Research shows. The South Australia experience is noteworthy in a global power mix set to increasingly shift to renewable energy. South Australia retired its last coal plant in 2016 and is projected to have installed renewable energy capacity exceed its peak demand by 2020.

By 2025, wind, solar and battery costs will fall by 15 percent, 25 percent and 50 percent respectively. By then, renewables and batteries could offer a lower cost alternative to combined-cycle gas turbine plants, which are commonly used to manage base load power generation in South Australia. Meanwhile by 2035, renewables and batteries will provide a commercial solution for both base loads and peak loads. As a consequence, gas will increasingly be used just for emergency back-up.

One determining factor is the rate with which battery charging costs declines. By 2025, we expect battery charging cost to decrease as off-peak prices will gradually be set by excess wind generation. Battery storage then becomes a potential solution for managing peak loads,” said Bikal Pokharel, principal analyst for Wood Mackenzie‘s Asia-Pacific power and renewables .
By 2025 it’s expected that 67 percent of South Australia’s power capacity will come from renewables. Gas demand in the power sector will then decline by 70 percent.

Currently, South Australia’s peak loads are managed by open-cycle gas turbine (OCGT) plants. But by 2025, battery storage would be cheaper than OCGTs in managing peak loads even at gas price of A$7/mmbtu. OCGTs would then be relegated as emergency back-ups.”


Cheap, Robust Catalyst Splits Water Into Hydrogen And Oxygen

Splitting water into hydrogen and oxygen to produce clean energy can be simplified with a single catalyst developed by scientists at Rice University and the University of Houston. The electrolytic film produced at Rice and tested at Houston is a three-layer structure of nickel, graphene and a compound of iron, manganese and phosphorus. The foamy nickel gives the film a large surface, the conductive graphene protects the nickel from degrading and the metal phosphide carries out the reactionRice chemist Kenton Whitmire and Houston electrical and computer engineer Jiming Bao and their labs developed the film to overcome barriers that usually make a catalyst good for producing either oxygen or hydrogen, but not both simultaneously.

A catalyst developed by Rice University and the University of Houston splits water into hydrogen and oxygen without the need for expensive metals like platinum. This electron microscope image shows nickel foam coated with graphene and then the catalytic surface of iron, manganese and phosphorus

Regular metals sometimes oxidize during catalysis,” Whitmire said. “Normally, a hydrogen evolution reaction is done in acid and an oxygen evolution reaction is done in base. We have one material that is stable whether it’s in an acidic or basic solution.

The discovery builds upon the researchers’ creation of a simple oxygen-evolution catalyst revealed earlier this year. In that work, the team grew a catalyst directly on a semiconducting nanorod array that turned sunlight into energy for solar water splittingElectrocatalysis requires two catalysts, a cathode and an anode. When placed in water and charged, hydrogen will form at one electrode and oxygen at the other, and these gases are captured. But the process generally requires costly metals to operate as efficiently as the Rice team’s catalyst.

The standard for hydrogen evolution is platinum,” Whitmire explained. “We’re using Earth-abundant materials — iron, manganese and phosphorus — as opposed to noble metals that are much more expensive.

The robust material is the subject of a paper in Nano Energy.


New Solar System Produces 50 Percent More Energy

A concentrating photovoltaic system (CPV) with embedded microtracking can produce over 50 percent more energy per day than standard silicon solar cells in a head-to-head competition, according to a team of engineers who field tested a prototype unit over two sunny days last fall.

Solar cells used to be expensive, but now they’re getting really cheap,” said Chris Giebink, Charles K. Etner Assistant Professor of Electrical Engineering, Penn State. “As a result, the solar cell is no longer the dominant cost of the energy it produces. The majority of the cost increasingly lies in everything else — the inverter, installation labor, permitting fees, etc. — all the stuff we used to neglect.

This changing economic landscape has put a premium on high efficiency. In contrast to silicon solar panels, which currently dominate the market at 15 to 20 percent efficiency, concentrating photovoltaics focus sunlight onto smaller, but much more efficient solar cells like those used on satellites, to enable overall efficiencies of 35 to 40 percent. Current CPV systems are large — the size of billboards — and have to rotate to track the sun during the day. These systems work well in open fields with abundant space and lots of direct sun.

What we’re trying to do is create a high-efficiency CPV system in the form factor of a traditional silicon solar panel,” said Giebink.


Move And Produce Electricity To Power Your Phone

Imagine slipping into a jacket, shirt or skirt that powers your cell phone, fitness tracker and other personal electronic devices as you walk, wave and even when you are sitting down. A new, ultrathin energy harvesting system developed at Vanderbilt University’s Nanomaterials and Energy Devices Laboratory has the potential to do just that. Based on battery technology and made from layers of black phosphorus that are only a few atoms thick, the new device generates small amounts of electricity when it is bent or pressed even at the extremely low frequencies characteristic of human motion.


In the future, I expect that we will all become charging depots for our personal devices by pulling energy directly from our motions and the environment,” said Assistant Professor of Mechanical Engineering Cary Pint, who directed the research.
This is timely and exciting research given the growth of wearable devices such as exoskeletons and smart clothing, which could potentially benefit from Dr. Pint’s advances in materials and energy harvesting,” observed Karl Zelik, assistant professor of mechanical and biomedical engineering at Vanderbilt, an expert on the biomechanics of locomotion who did not participate in the device’s development.

Doctoral students Nitin Muralidharan and Mengya Lic o-led the effort to make and test the devices. When you look at Usain Bolt, you see the fastest man on Earth. When I look at him, I see a machine working at 5 Hertz, said Muralidharan.

The new energy harvesting system is described in a paper titled “Ultralow Frequency Electrochemical Mechanical Strain Energy Harvester using 2D Black Phosphorus Nanosheets” published  by the journal ACS Energy Letters.


How To Power The U.S. With Solar

Speaking recently at the National Governors Association Summer Meeting in Rhode Island, Elon Musk told his audience — including 30 United States governors — that it’s possible to power the nation with solar energy.

If you wanted to power the entire U.S. with solar panels, it would take a fairly small corner of Nevada or Texas or Utah; you only need about 100 miles by 100 miles of solar panels to power the entire United States,” Musk said. “The batteries you need to store the energy, to make sure you have 24/7 power, is 1 mile by 1 mile. One square-mile. That’s it.”

Why solar? Well, as Musk explained, as far as energy sources go, we can count on solar to come through for us: “People talk about fusion and all that, but the sun is a giant fusion reactor in the sky. It’s really reliable. It comes up every day. If it doesn’t we’ve got bigger problems.”

At present, about 10 percent of the U.S. is powered by renewable energy sources. To achieve a complete renewable energy power, Musk thinks solar is the way to go.

To start, he suggested combining rooftop solar and utility-scale solar plants. The former would be on the rooftops of houses in the suburbs, while the latter could power other areas. As we’ve seen with Tesla’s new rooftop solar unit, and efforts in other countries, like Australia, to build large-scale solar plants, this is a goal well within reach.

Next, while in transition from fossil fuel to solar, it’d be necessary to rely on other renewables. “We’ll need to be a combination of utility-scale solar and rooftop solar, combined with wind, geothermal, hydro, probably some nuclear for a while, in order to transition to a sustainable situation,” Musk explained.

Finally, the U.S. has to build more localized power sources, like the rooftop solar setups. “People do not like transmission lines going through their neighborhood, they really don’t like that, and I agree,” Musk said. “Rooftop solar, utility solar; that’s really going to be a solution from the physics standpoint. I can really see another way to really do it.”

When this happens, the U.S. would eliminate about 1,821 million metric tons of carbon dioxide (CO2) emissions generated by the country’s current electric power sector — 35 percent of the overall CO2 energy-related emissions in the U.S.