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Supercomputer Network Simulates Material That Might Not Melt in a Sunspot

Computer simulations can save time and money when investigating new technical designs but also when looking for new materials. Some serious supercomputing helped two scientists at Brown University in Providence, RI, to—virtually—break a melting-point record.

The current record is held by a mixture of hafnium, tantalum, and carbon (Ta4HfC5), which melts at 4,215 K (3942 oC).  The Brown scientists predicted that a material made up from a mixture of hafnium, nitrogen, and carbon, could have an even higher melting point, 4,400 K (4127 oC), which is about two thirds the temperature at the sun's surface. (Sunspots range from 3000 – 4500 K, so such a material would probably stay solid in one.) At that temperature, the theoretical material would emit light with an intensity about one third of the sun’s surface. The researchers, Axel van de Walle and Qi-Jun Hong, published the results of the computer simulations of this compound in the journal Physical Review B on in June.

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Renewables to Overtake King Coal Under Obama Carbon Regs

At the White House on Monday, President Obama announced final rules intended to cut carbon emissions from the electric power sector by nearly one-third by 2030. The rules, part of Obama's Clean Power Plan, are projected to turn the tables on today’s power supply mix, putting King Coal one rung below renewable power sources. 

The U.S. Environmental Protection Agency (EPA) projects that full compliance with the rules will drive down the portion of the nation’s power supply that comes from burning coal to 27 percent by 2030—a major slip from its 39 percent share in 2013. Renewables will more than double their share of U.S. power generation over the same period, rising from 13 percent to 28 percent, projects the EPA.

Natural gas–fired generation is expected to maintain its current role of roughly 27 percent, rather than grow substatially as predicted when EPA released its draft plan in June 2014.

Timelines for initial compliance, meanwhile, have slipped back two years to 2022. This is mainly the result of the power industry’s complaint that a compliance regime beginning in 2020 would spur a rushed shuttering of coal-fired power plants and increase the risk of power grid blackouts

Despite the delay, however, the final rule is actually projected to achieve greater carbon reductions. By 2030, the EPA projects, carbon emissions from the power sector will be 32 percent lower than their 2005 level, an improvement on the 30 percent goal in the EPA’s 2014 proposal. This reflects, to a large extent, the carry-forward effect of strong recent growth in installations of renewable generation such as solar panels.

Obama said the pledged action by the United States sets the stage for an international deal at the Paris climate change negotiations to take place later this year. “In December, with America leading the way, we have the chance to put together one of the most ambitious international climate agreements in history,” said Obama.

The North American Electric Reliability Corporation (NERC), which sets grid standards, issued a statement yesterday saying it was pleased that “the final rule addresses several topics identified as needing attention” in its evaluations of EPA’s proposal. “NERC’s principal finding recommended additional time in order to allow for extensive planning and significant investments in new energy infrastructure that will be needed to achieve emission reduction goals,” said NERC in its statement. 

The Washington, D.C.-based Edison Electric Institute, a trade group representing investor-owned utilities, struck an equally conciliatory tone. In a statement issued yesterday, EEI president Tom Kuhn welcomed the flexibility offered by the final rules and said they would “work with the states” as they develop plans to comply with the rules. “Today utilities are focused on the transition to a cleaner generating fleet,” said Kuhn.

Many leaders in the Republican party continue to express serious doubts as to the existence of climate change, or of its human origins, and adjusting the deadlines did not shake their opposition to Obama’s Clean Power Plan. However, Obama’s plan may pencil out even without its climate benefits. EPA Administrator Gina McCarthy has estimated that, thanks largely to the health benefits from reduced smog and soot emissions under the plan, its economic benefit will be 4 to 7 times larger than the $8.4 billion in costs that the EPA is projecting through 2030. 

At yesterday’s White House ceremony, Obama recalled an early personal experience with air pollution, and drew a lesson about critics of air pollution controls. Obama said his lungs constricted when he went running on his first day in Los Angeles in 1979, fresh off an airplane from Hawaii to attend Occidental College. “After about 5 minutes I had this weird feeling like I couldn’t breathe,” recalled the President. 

Obama predicted that, just as ingenuity triumphed over pessimism to clean up LA’s air, innovation and determination could deliver a lower-carbon power system in the years ahead without bankrupting the U.S. or global economies. “Because we pushed through despite those scaremongering tactics, you can actually run in LA without choking. We’ve got to learn lessons and know our history. We can figure this stuff out. We can upend old ways of thinking,” said Obama.

One such innovation is highlighted in the pages of this month’s issue of Spectrum: repurposing old power plant generators to function as voltage stabilizers, thus facilitating the importation of power from more distant power plants or intermittent renewable energy sources. Turning aging coal, gas and nuclear plants into synchronous condensers is a new spin on a rather old idea -- one that’s likely to have even more relevance thanks to the Clean Power Plan. 


Solar Cells Could Capture Infrared Rays for More Power

Solar cell efficiencies could increase by 30 percent or more with new hybrid materials that make use of the infrared portion of the solar spectrum, researchers say.

Visible light accounts for under half of the solar energy that reaches Earth's surface. Nearly all of the rest comes from infrared radiation. However, solar infrared rays normally passes right through the photovoltaic materials that make up today's solar cells.

Now scientists at the University of California, Riverside, have created hybrid materials that can make use of solar infrared rays. The energy from every two infrared rays they capture is combined or “upconverted” into a higher-energy photon that is readily absorbed by photovoltaic cells, generating electricity from light that would normally be wasted.

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Boosting the Transfer Efficiency of Wireless Power Transfer Systems

The wireless transfer of electric current that charges your electric toothbrush is highly efficient: The receiver coil in the handle of the toothbrush fits tightly around the transmitter coil in the charger, making the process about as lossless the operation of the ubiquitous transformer. 

However, using wireless power transfer for electric cars by charging them with transmitter coils embedded in the pavement is more problematic.  The receiver coil in the car has to be placed as close as possible to the ground; still, only a part of the transmitted energy reaches the receiver coil. 

Now researchers from North Carolina State University and Carnegie Mellon University say they have hit upon a way to boost the efficiency of the energy transfer in that situation. They reported, in a paper published in the online edition of the journal IEEE Antennas and Wireless Propagation Letters, that by placing a magnetic resonance field enhancer (MRFE)—a loop of copper wire resonating at the same frequency as the AC current feeding the transmitter coil—between the transmitter and receiver coil, they could boost the transmission efficiency by at least 100 percent. “Our experimental results show double the efficiency using the MRFE in comparison to air alone,” David Ricketts of NC State, said in a press release. The MRFE increases the strength of the magnetic field that reaches the receiver coil, resulting in an increase of the transmission efficiency.

Previously, the team had investigated the use of metamaterials to enhance the magnetic field. “We performed a comprehensive analysis using computer models of wireless power systems and found that MRFE could ultimately be five times as efficient as using metamaterials and offer 50 times the efficiency of transmitting through air alone,” Ricketts says.  

For their experimental setup, the team used two coils of 4.25-centimeter- diameter copper wire with six turns for the transmitter and receiver coils.  The coils were separated by 12.2 cm and the transmitter coil was powered with a 2.94-megahertz signal. They measured the transmission efficiency by placing a metamaterial between the transmitter and receiver coil and comparing it with a setup where a single, 12-cm-diameter copper-wire loop replaced the metamaterial. They found that the copper wire version improved the efficiency by a factor of almost two.

These laboratory experiments, though much smaller systems than would be used in the future applications the researchers envision, clearly indicate how transmission efficiency could be tweaked. “This [research] could help advance efforts to develop wireless power transfer technologies for use with electric vehicles, in buildings, or in any other application where enhanced efficiency or greater distances are important considerations,” Ricketts says.


Digging for Geothermal Energy with Hypersonic Projectiles

Geothermal energy might be the most appealing of all renewables. Unlike wind, solar, or even wave or tidal energy, it produces constant and reliable long-term power. Iceland has got this all figured out, but they have it easy. The entire country is (luckily) perched on top of an active volcano. For the rest of us, tapping into geothermal power is harder, because you have to dig for it: About 5 kilometers down, you can find rock hot enough to turn water into steam.

The average depth of an oil well is only about a kilometer and a half, and drilling down to 5 km (especially through hard rock) using conventional technology isn’t trivial and definitely not worth the cost. A company called HyperSciences thinks it has a better way. It wants to harness geothermal energy with a new kind of drilling technology that does away with the “drill” bit completely, using projectiles fired into the ground instead.

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Porous Silicon Battery Electrodes from Reeds

Natural structures in reed leaves could find use in advanced lithium-ion batteries, which could lead to a more sustainable way to create sophisticated energy-storage devices, scientists in China and Germany say.

Silicon-based materials can theoretically store more than 10 times charge than the carbon-based materials most commonly used in the anodes of commercial lithium-ion batteries, making them promising next-generation anode materials. However, silicon’s big problem is that it can swell by more than 300 percent when filled with lithium. The constant swelling and shrinking as the battery charges and discharges, causes the anode to crack. One way to overcome this problem is to make silicon porous enough to accommodate the expansion. But synthesizing these structures is commonly a complex, energy-intensive, and costly process.

Now scientists have developed 3-D porous silicon-based anode materials using the kind of reed leaves that are abundant in temperate wetlands. Reeds naturally absorb silica from the soil, which accumulates in sheet-like structures around micro-compartments in the plants.

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Micrograph of nanowires protruding vertically from a surface.

Nanowires Boost Hydrogen Production from Sunlight Tenfold

Using the energy of the sun to split water into hydrogen and oxygen gives you access to a completely carbon-free energy source for transportation. But so far, the efficiency of the process has been a bit disappointing, even when using systems called solar-fuel cells—a solar cells immersed in the water it’s splitting.

Now researchers from Eindhoven University of Technology in The Netherlands and the Dutch Foundation for  Fundamental Research on Matter (FOM) report in the 17 July issue of Nature Communications  that they have improved tenfold the hydrogen producing capacity of a solar fuel cell. The key was to use a photocathode—the electrode that supplies electrons when illuminated by sunlight—made from an array of gallium phosphide nanowires.

Previously, researchers used flat surfaces of the semiconductor gallium phosphide as the photocathode, but light absorption was low.  The GaP nanowires, about 500 nm long and 90 nm thick, increased enormously the surface of the photocathode exposed to light.  By adding platinum particles, its catalytic properties improved hydrogen production even more, report the researchers.

At the same time, the nanowires allowed a drastic reduction in the use of GaP material. “For the nanowires we needed ten thousand times less precious GaP material than in cells with a flat surface. That makes these kinds of cells potentially a great deal cheaper,” said Erik Bakkers of Eindhoven University of Technology, as quoted in a press release.

“In addition, GaP is also able to extract oxygen from the water—so you then actually have a fuel cell in which you can temporarily store your solar energy. In short, for a solar fuels future we cannot ignore gallium phosphide any longer,” he added.


Diesel-Powered Fuel Cell Produces Clean Electricity

Although several options to store hydrogen as a fuel for cars have been investigated, a practical and affordable way to store and distribute hydrogen is still the biggest hurdle to the wide deployment of green, CO2-emission-free cars. Now researchers in Europe have built a demonstration system that might be a first step in circumventing the limitations on hydrogen distribution and storage; they simply extract hydrogen from diesel fuel on the go.  

The research group, "Fuel Cell Based Power Generation (FCGEN)," which includes researchers from Volvo Technology (Sweden), Johnson-Matthey (United Kingdom), Modelon AB (Sweden), PowerCell AB (Sweden), Jožef Stefan Institute (Ljubljana, Slovenia), Forschungszentrum Jülich (Germany) and Fraunhofer ICT-IMM (Mainz, Germany) announced in a recent press release the creation of a prototype 3-kilowatt, diesel-fueled fuel cell system that has operated flawlessly for 10,000 hours. 

The extraction of the hydrogen from the diesel fuel happens through autothermal reforming, a catalytic reaction in which the diesel fuel is decomposed into hydrogen, steam, carbon dioxide, and carbon monoxide.  The CO is then converted to CO2 and water, explains Boštjan Pregelj of the Jožef Stefan Institute, and who is the Principal Investigator of the FCGEN project.

It didn’t escape their notice that the extraction of hydrogen from the diesel fuel releases CO2 directly into the atmosphere.  “Actually all carbon in the diesel is converted to CO2, but since the efficiency [of the overall process] is about five times [that of a diesel] engine idling, fuel consumption is 80 percent lower, and consequently, the produced amount of CO2 is decreased by 80 percent,” says Pregelj. That is why the “green” label was given."

The researchers say that the system could generate between 3 and 10 kW of power in trucks; on small aircraft, it would power air conditioners and refrigeration systems. In addition to lowering CO2 emission, the units produce little noise, making them suitable as mobile electricity generators in places, like field hospitals, where quiet is appreciated. 


Transactive Energy Controls Survive First Test in Pacific Northwest

For the past five years, a consortium of researchers, technology companies, and power utilities have been testing a novel power delivery system in the Pacific Northwest of the United States.

The Pacific Northwest Smart Grid Demonstration project was far reaching and had more than 50 experiments, but the most cutting edge was testing transactive controls for the power grid. The project was led by Battelle and funded by the U.S. Department of Energy. 

Transactive control involves an automated communication and control system connecting energy providers and users, who constantly exchange information about price and availability of power. When an energy provider predicts a surge in power demand, and therefore also higher prices, for example, it sends out this information as “transactive signals” to the rest of the network, including users. Based on these signals, smart grid technologies can react, reducing power use at the right time. The goal is improving reliability and efficiency, allowing for more dynamic balancing of resources, especially in regions that rely on high levels of renewables.

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Antineutrino Detectors Could Be Key to Monitoring Iran's Nuclear Program

President Obama has made it clear in a statement that the Iran nuclear deal signed yesterday was “built on verification.” Technology built to detect an elusive subatomic particle called the antineutrino could help.

The International Atomic Energy Agency wants a reactor-monitoring tool that is portable, safe, inexpensive, and remotely controllable. Antineutrino detectors, which give a peek into how much uranium and plutonium are in a reactor core, promise all of that.

The technology, which has been in the works since the early 2000s, has improved tremendously in the past five years, and it is now almost ready for practical use, says Patrick Huber, a physics professor at the Center of Neutrino Physics at Virginia Tech in Blacksburg. “Less than two years from now, you should have at least one maybe several types of antineutrino detector technologies that would work as nuclear safeguard detectors.”

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