This is a guest post by Josephine Ferorelli, originally published at Occupy.com. There is not enough room in the national headlines for all the battles between fossil fuel expansion projects and climate activists occurring right now. But the Keystone XL proposal’s public comment period ends on April…
But there are limits that could hold wind back from growing
A new study from Harvard University’s School of Engineering and Applied Sciences says that the generating capacity of large-scale wind farms isn’t quite as high as scientists previously thought.
The study was led by Harvard applied physicist David Keith, who showed that we may not have access to as much wind power as once thought. Keith is an internationally renowned expert on climate science.
According to Keith’s study, individual wind turbines each create a “wind shadow,” which is where air is slowed by the drag on the turbine’s blades. Wind farms with as many turbines packed into an area as possible but with just the right amount of spacing in between them are optimal for decreasing this drag.
However, the larger these wind farms are, the more they communicate and regional-scale wind patterns are even more important. Keith said previous generating capacity of large-scale wind farms ignored the drags and these wind patterns.
Keith’s study said that the generating capacity of large-scale wind farms that are larger than 100 square kilometers could peak anywhere from 0.5 and 1 watts per square meter. Prior estimates put these figures at 2 to 7 watts per square meter.
“If wind power’s going to make a contribution to global energy requirements that’s serious, 10 or 20 percent or more, then it really has to contribute on the scale of terawatts in the next half-century or less,” said Keith.
But there are limits that could hold wind back from growing. Keith said that if wind were to exceed 100 terawatts, it would have a huge impact on global winds and eventually climate — which could negatively affect climate more than doubling CO2.
“Our findings don’t mean that we shouldn’t pursue wind power—wind is much better for the environment than conventional coal—but these geophysical limits may be meaningful if we really want to scale wind power up to supply a third, let’s say, of our primary energy,” said Keith.
“It’s clear the theoretical upper limit to wind power is huge, if you don’t care about the impacts of covering the whole world with wind turbines . What’s not clear—and this is a topic for future research—is what the practical limit to wind power would be if you consider all of the real-world constraints. You’d have to assume that wind turbines need to be located relatively close to where people actually live and where there’s a fairly constant wind supply, and that they have to deal with environmental constraints. You can’t just put them everywhere.”
Keith concluded that we’ll need to find sources for tens of terawatts of carbon-free power “within a human lifetime” in order to stabilize the Earth’s climate.
“It’s worth asking about the scalability of each potential energy source—whether it can supply, say, 3 terawatts, which would be 10 percent of our global energy need, or whether it’s more like 0.3 terawatts and 1 percent,” said Keith.
Source: Harvard University
Feb. 24, 2013 — A new method of harvesting the Sun’s energy is emerging, thanks to scientists at UC Santa Barbara’s Departments of Chemistry, Chemical Engineering, and Materials. Though still in its infancy, the research promises to convert sunlight into energy using a process based on metals that are more robust than many of the semiconductors used in conventional methods.
The researchers’ findings are published in the latest issue of the journal Nature Nanotechnology.
“It is the first radically new and potentially workable alternative to semiconductor-based solar conversion devices to be developed in the past 70 years or so,” said Martin Moskovits, professor of chemistry at UCSB.
In conventional photoprocesses, a technology developed and used over the last century, sunlight hits the surface of semiconductor material, one side of which is electron-rich, while the other side is not. The photon, or light particle, excites the electrons, causing them to leave their postions, and create positively-charged “holes.” The result is a current of charged particles that can be captured and delivered for various uses, including powering lightbulbs, charging batteries, or facilitating chemical reactions.
“For example, the electrons might cause hydrogen ions in water to be converted into hydrogen, a fuel, while the holes produce oxygen,” said Moskovits.
In the technology developed by Moskovits and his team, it is not semiconductor materials that provide the electrons and venue for the conversion of solar energy, but nanostructured metals — a “forest” of gold nanorods, to be specific.
For this experiment, gold nanorods were capped with a layer of crystalline titanium dioxide decorated with platinum nanoparticles, and set in water. A cobalt-based oxidation catalyst was deposited on the lower portion of the array.
“When nanostructures, such as nanorods, of certain metals are exposed to visible light, the conduction electrons of the metal can be caused to oscillate collectively, absorbing a great deal of the light,” said Moskovits. “This excitation is called a surface plasmon.”
As the “hot” electrons in these plasmonic waves are excited by light particles, some travel up the nanorod, through a filter layer of crystalline titanium dioxide, and are captured by platinum particles. This causes the reaction that splits hydrogen ions from the bond that forms water. Meanwhile, the holes left behind by the excited electrons head toward the cobalt-based catalyst on the lower part of the rod to form oxygen.
According to the study, hydrogen production was clearly observable after about two hours. Additionally, the nanorods were not subject to the photocorrosion that often causes traditional semiconductor material to fail in minutes.
“The device operated with no hint of failure for many weeks,” Moskovits said.
The plasmonic method of splitting water is currently less efficient and more costly than conventional photoprocesses, but if the last century of photovoltaic technology has shown anything, it is that continued research will improve on the cost and efficiency of this new method — and likely in far less time than it took for the semiconductor-based technology, said Moskovits.
“Despite the recentness of the discovery, we have already attained ‘respectable’ efficiencies. More importantly, we can imagine achievable strategies for improving the efficiencies radically,” he said.
Research in this study was also performed by postdoctoral researchers Syed Mubeen and Joun Lee; grad student Nirala Singh; materials engineer Stephan Kraemer; and chemistry professor Galen Stucky.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Posted February 23, 2013 – 18:39 by David Konow
With the advent of The Walking Dead, zombies are more popular now than ever before.
Interestingly enough, GiantFreakinRobot and the Huffington Post recently ran a story about biologists developing zombie cells.
No, this is not something out of I Am Legend where a virus gets out and created zombies everywhere, don’t panic, this was an experiment developed in Sandia National Laboratories and the University of New Mexico biology labs where they developed “zombie-like” cells.
As the Post tells us, mammalian cells are coated with silica, and it makes replicas that are nearly perfect to the original. The silica protects the cells, and they can keep living at higher temperatures and pressures than the first living cells. At 400 degrees, the protein of the cell evaporates, but a three-dimensional replica of the “formerly living being” is left behind, thanks to the silica.
The head researcher said, “Our zombie cells bridge chemistry and biology to create forms that not only near-perfectly resemble their past selves, but can do future work.” But as Robot tells us, this is not for the development of creating zombies, thankfully. This is to try and create fossils that we can create fuels from.
“That’s right,” writes Rudie Obias. “Zombie gasoline for cars, boats, and airplanes.” Could this eventually end all energy crises and we’ll never have to go to war with the Middle East over oil again? That would be cool, no? And we thought electric cars and going solar were going to save us.
In other undead news, you read our report on TG about hackers pulling a zombie prank in Montana. The pranksters got onto the local station KRTV, and played an emergency warning that the undead were attacking. This thankfully did not result in wide-spread panic, the TV viewers who saw the warning apparently got the joke, but the FCC didn’t find this very amusing.
In fact, according to Media Bistro, the Federal Communications Commission has been telling TV stations to “take immediate action” and make sure their Emergency Alert Systems are more secure after this zombie hacker prank.”
Again, people got the joke, but you never know. Without a disclaimer that the whole thing’s in fun, maybe there could be an undead panic down the road, especially if The Walking Dead stays on top in the ratings, and zombie cells becomes the energy source of the future.
An array on nano energy harvesters in what the researchers call a “swiss cheese” arrangement. (Credit: Image courtesy of University of Rochester)
Feb. 14, 2013 — A new type of nanoscale engine has been proposed that would use quantum dots to generate electricity from waste heat, potentially making microcircuits more efficient.
“The system is really a simple one, which exploits certain properties of quantum dots to harvest heat,” Professor Andrew Jordan of the University of Rochester said. “Despite this simplicity, the power it could generate is still larger than any other nanoengine that has been considered until now.”
The engines would be microscopic in size, and have no moving parts. Each would only produce a tiny amount of power — a millionth or less of what a light bulb uses. But by combining millions of the engines in a layered structure, Jordan says a device that was a square inch in area could produce about a watt of power for every one degree difference in temperature. Enough of them could make a notable difference in the energy consumption of a computer.
A paper describing the new work is being published in Physical Review B by Jordan, a theoretical physics professor, and his collaborators, Björn Sothmann and Markus Buttiker from the University of Geneva, and Rafael Sánchez from the Material Sciences Institute in Madrid.
Jordan explained that each of the proposed nanoengines is based on two adjacent quantum dots, with current flowing through one and then the other. Quantum dots are manufactured systems that due to their small size act as quantum mechanical objects, or artificial atoms.
The path the electrons have to take across both quantum dots can be adjusted to have an uphill slope. To make it up this (electrical) hill, electrons need energy. They take the energy from the middle of the region, which is kept hot, and use this energy to come out the other side, higher up the hill. This removes heat from where it is being generated and converts it into electrical power with a high efficiency.
To do this, the system makes use of a quantum mechanical effect called resonant tunneling, which means the quantum dots act as perfect energy filters. When the system is in the resonant tunneling mode, electrons can only pass through the quantum dots when they have a specific energy that can be adjusted. All other electrons that do not have this energy are blocked.
Quantum dots can be grown in a self-assembling way out of semiconductor materials. This allows for a practical way to produce many of these tiny engines as part of a larger array, and in multiple layers, which the authors refer to as the Swiss Cheese Sandwich configuration (see image).
How much electrical power is produced depends on the temperature difference across the energy harvester — the higher the temperature difference, the higher the power that will be generated. This requires good insulation between the hot and cold regions, Jordan says.
Share this story on Facebook, Twitter, and Google:
Other social bookmarking and sharing tools:
Posted February 13, 2013 – 06:45 by Emma Woollacott
Korean engineers have developed a new wireless power transfer technology for railways, harbor freight and airport.
The Korea Advanced Institute of Science and Technology (KAIST) and the Korea Railroad Research Institute (KRRI) today successfully tested it out on railroad tracks at Osong Station.
The technology supplies 60 kHz and 180 kW of power remotely to transport vehicles at a stable, constant rate, they say. It was developed originally as part of an electric vehicle system introduced by KAIST in 2011 known as the On-line Electric Vehicle (OLEV).
The first models, a bus and a tram, tap 20 kHz and 100 kW power at an 85 percent transmission efficiency rate, while keeping a 20cm air gap between the underbody of the vehicle and the road surface.
Today’s demonstration of the technology in a train shows that OLEV can be used successfully in larger-scale systems.
“We have greatly improved the OLEV technology from the early development stage by increasing its power transmission density by more than three times. The size and weight of the power pickup modules have been reduced as well,” says Professor Dong-Ho Cho of KAIST.
“We were able to cut down the production costs for major OLEV components, the power supply, and the pickup system, and in turn, OLEV is one step closer to being commercialized.”
KAIST and KRRI plan to apply the wireless power transfer technology to trams in May and high speed trains in September.
Posted February 13, 2013 – 07:00 by Randy Woods, EarthTechling
The goal of many green designs for houses is to make them appear part of the landscape.
In the Netherlands, the firm 123DV has created a home that is far too linear to be called organic, but still manages to feel as it is part of the hill upon which it sits, especially since the hill itself is also man-made.
The “Bridge House,” as it is known, is located on a wide, grassy knoll in a park near the town of Achterhoek. Like most of the landscape in the Netherlands, it has been shaped by both new and ancient human forces. Though the house is utterly modern in shape and design, it uses the traditional Dutch “terp” method of building a low mound and partially embedding the cellar in the earth to harness the geothermal properties of the surrounding soil.
The simple box shape appears to sit lightly atop the hill, but it is truly part of the earthworks, with most of the lower floor buried in the terp mound. Only a small trapezoidal section of the foundation is revealed in a shallow trough that is cut into the gently sloping hillside, framing the house’s main entrance.
The original intent of the terp style of building was to protect houses and entire villages from incoming tides before the massive dike systems of Holland were constructed. Today, the terps are used more for temperature control. By harnessing the earth’s thermal storage properties, the half-buried house is kept cool in the summer and warm in winter without needing extra electricity.
In fact, the Bridge House has enough green design elements to be completely self-sufficient, should the need arise. In addition to the geothermal system in the roof and marble floors, drinking water is supplied by an on-site well, solar panels supply all the needed electricity, wastewater is treated in a septic field, and rainwater is collected for reuse on the landscaping, which includes wildflowers, 1,000 rhododendrons and 17,000 trees that were all planted on the property by hand.
Even the extensive use of floor-to-ceiling glass—always a thermal bane of modern design—is mitigated somewhat by the inclusion of “heat-mirror glass.” This double-paned glass includes a reflective coating that reflects part of the sun’s rays and blocks excess heat from entering.