- Laser Guidance Adds Power to Wind Turbines
- Chemical Fingerprints Could Finger Weapons Makers
- As Temperature Rises, Earth Breathes Faster — and Maybe Harder
- Female Chimpanzees Drive the Culture
Posted: 25 Mar 2010 11:45 AM PDT
The wind industry may soon be dependent on a different kind of environmental awareness that has more to do with lasers than ecology.
A new laser system that can be mounted on wind turbines allows them to prepare for the wind rushing toward their blades.
The lasers act like sonar for the wind, bouncing off microscopically small particulates and back to a fiber optic detector. That data is fed to an on-board processor that generates a three-dimensional view of the wind speed and direction. Subtle adjustments in the turbine blade's angle to the window allows it to capture more energy and protect itself in case of strong gusts.
The startup company that developed the Vindicator system, Catch the Wind, recently deployed a wind unit on a Nebraska Public Power District turbine. It increased the production of the unit (.pdf) by more than 10 percent, according to the company's white paper. If those numbers held across the nations' 35 gigawatts of installed wind capacity, the LIDAR (Light Detection and Ranging) sensors could add more than 3.5 gigawatts of wind capacity without adding a single additional turbine.
"This is what they call disruptive technology," said William Fetzer, vice president of business development for Catch the Wind. "There are roughly 80,000 to 90,000 wind turbines out in the world, and they don't have this technology."
Wind farms are only as good as their data. There have been revolutions in assessing wind resources over long time-scales, but the short-term gustiness of the wind has remained a problem.
Current wind turbines rely on wind-measuring instruments known as anemometers that are mounted to the back of the turbine's gear-housing unit, called a nacelle. The data from the wind is fed to a computer that optimizes the blades' configuration to capture the most energy from the wind.
In many cases, cup anemometers, which took their current form in the 1930s, are still used. They work well enough, but have to be positioned behind the blades, which subjects them to turbulence. And, importantly, they can only tell you how fast the wind was blowing after it passed. That doesn't help you with a freak gust of wind or any of the odd behavior that renewable energy developers have caught the wind exhibiting.
Fort Felker, director of the National Renewable Energy Laboratory's National Wind Technology Center, said he saw great potential in LIDAR and similar sound-wave-based systems generally.
"Once you have a detailed knowledge of the coming wind, there are a lot of opportunities," said Felker told Wired.com.
While he estimates the amount of energy that could be captured is below Catch the Wind's 10 percent, he said the systems could really help reduce the wear-and-tear on machines caused by strong winds hitting improperly positioned blades.
"Researchers have already demonstrated that substantial reduction of loads is certainly possible," Felker said.
LIDAR, despite first being demonstrated for wind measurement in the 1970s, has been slow to catch on. The systems have been too expensive.
"Widespread deployment of the technique has so far been hampered by the expense and complexity of LIDAR systems," (.pdf) a 2005 NREL research report found. "However, the recent development of LIDAR systems based on optical fiber and components from the telecommunications industry promises large improvements in cost, compactness, and reliability so that it becomes viable to consider the deployment of such systems on large wind turbines."
Now, even the most venerable R&D testing group in the world, the Danish National Laboratory for Sustainable Energy's Risøe wind outfit, is working on a turbine-mounted LIDAR system, though they only claim a 5 percent increase in electricity production.
Catch the Wind grew out of a small-business grant that the company's predecessor, Optical Air Data Systems, received from the U.S. military. They developed a LIDAR system for helicopters working in the dusty Iraq and Afghanistan terrain. The company developed their rugged and relatively lightweight LIDAR systems by marrying aerospace knowledge with emerging telecommunications tech like better fiber optic cables and laser diodes.
Still, Catch the Wind may have a tough road ahead. The energy industry is notoriously risk averse. Besides, wind electricity in many places is already cheaper than wholesale electricity prices.
Erin Edholm, a representative for National Wind, a wind-farm developer that's put in more than 4,000 megawatts of turbines, said that the company's wind resource assessment team "has not used [LIDAR] or considered using it to date."
But that doesn't dim the hopes of Catch the Wind's Fetzer for the company's ultimate success.
"When you do disruptive technologies, it takes time," Fetzer said. "People don't believe that things are as bad as they are until they can see what we can do."
It helps that they don't need the wind turbine manufacturers to incorporate their technology to jump start their business. They've got what's known as a "bolt-on" solution, meaning it can be attached to existing turbines. They don't need manufacturers to incorporate their product to sell it to wind farms.
Still, some wind farmers may worry that the warranties they have on their turbines would be voided by adding a LIDAR system. Fetzer said Catch the Wind is working out the warranty issues.
General Electric, which is the largest wind turbine manufacturer in the United States, is not using or developing LIDAR specifically, either. Catch the Wind did recently sell one of their machines to a large, unnamed turbine manufacturer.
Though Catch the Wind is not discussing pricing for their products, Fetzer maintains that their customers will make their money back in the three-to-five year range that he says wind developers are looking for. The 2005 NREL report calculated a preliminary cost for a generic LIDAR system of less than $95,000, once production was up and running.
The development of controls for capturing the most energy from the wind has been a constant theme in wind energy research. But it's not always the company that develops the technology that reaps the rewards from its commercialization. Wind turbines in the 1980s struggled mightily to convert the wind's gusty capriciousness into steady rotary power.
At the time, the turbine's rotor had to turn at a constant rate. Researchers realized that their machines could operate over a larger range of speeds if the rotor could speed up or slow down in response to the wind, but they would need power electronics to translate the power into electricity suitable for the grid.
A multimillion dollar R&D program launched by U.S. Windpower and the Electric Power Research Institute to commercialize a variable-speed rotor resulted in a mostly defective turbine design that helped push U.S. Windpower out of business. The variable-speed rotor went on to become a standard part of wind turbine designs.
Catch the Wind obviously is hoping not to suffer the same fate. They are exploring a variety of business models including sharing the revenue from the extra power they say their systems can generate. If they don't generate any more electricity, the wind turbine owner doesn't pay anything. If they do, Catch the Wind gets half the take.
"It's a good value proposition," Fetzer concluded.
Images: 1. A Vindicator installed in Nebraska/Catch the Wind. 2. American Memory Collection.
Posted: 25 Mar 2010 10:47 AM PDT
SAN FRANCISCO — Finding out whodunit in chemical warfare cases may be aided by scientists focused on the howdunit.
Researchers have developed a technique to ascertain the chemical fingerprint of compounds such as mustard gas, rat poison and nerve agents such as VX. Figuring out the details of how these compounds were created in the first place could provide vital clues to law enforcement agencies aiming to catch chemical warfare criminals and help guide first responders as they gather evidence.
Chemical forensics typically focuses on identifying the compound in question, but chemist Audrey Martin and her colleagues at Lawrence Livermore National Laboratory in California wanted to take these analyses a step further. "If we already know this was a chemical attack using mustard gas, now we want to know who made it," said Martin, who presented the research March 22 in a poster session at a meeting of the American Chemical Society held in San Francisco. "We're looking at the next step — where did this come from?"
The technique relies on the fact that there are often many routes to the same chemical — for example there are 12 different ways of making sulfur mustard gas. Depending on the route and the ingredients, there are various chemical by-products, impurities and unreacted ingredients in the final product. The presence and proportions of these molecules can provide clues to how the compound was made, said Martin. In some cases, such as with the rat poison tetramine, one synthetic route might be ruled out entirely by the presence of a particular ingredient. Signatures of the reaction conditions, such as temperature and pressure, may also be hidden in the final product.
So far, the Lawrence Livermore team has determined these various chemical signatures for a handful of compounds, including Sarin gas and the toxic nerve agent VX. The team is also documenting how these chemicals evolve over time, so scientists can tell if something has been sitting around for five minutes, 20 minutes or a week.
Martin has developed a computer application that she can feed these signatures into, minimizing time spent manually comparing chemical profiles. The researchers are also investigating how such agents interact with food and surfaces such as tile, plastic and metal. This information could help guide first responders charged with sampling a contaminated area, said Martin.
"It's not a smoking gun," she cautions. But if a suspect was seen purchasing a particular ingredient, or has a telltale residue on a shirtsleeve, the method might help clinch a case.
Posted: 25 Mar 2010 10:18 AM PDT
As planetary temperatures rise, Earth's soils release steadily larger amounts of carbon dioxide, according to massive data crunching from hundreds of soil respiration studies published since 1989.
The critical question is whether soils release more CO2 because faster-growing plants pump more in, or if soils release CO2 that would have stayed in the ground at lower temperatures.
If the latter, the fresh influx of CO2 could produce a self-reinforcing cycle, producing higher temperatures that cause even more CO2 to be released.
"That's the $50,000 question: Is there a feedback effect?" said Ben Bond-Lamberty, a University of Maryland, College Park biogeochemist and co-author of the review, in the March 24 Nature. "The data we have implies a feedback. It doesn't prove it, but it's consistent with the possibility."
Carbon dioxide enters the soil through the roots of living plants and from the decaying bodies of dead plants, and is processed by microbes, fungi and insects. Over time, some of that CO2 releases back into the atmosphere. At any given time, there's about twice as much CO2 in Earth's soils as in its atmosphere.
Because more heat means more energy and faster chemical reactions, Earth scientists have suspected that rising global temperatures would increase the rate of soil respiration. The last review of soil respiration studies (.pdf) took place in 1992, however, and though it found a link between temperature and respiration rates, data was relatively sparse.
In the Nature paper, Bond-Lamberty and fellow UMCP geoscientist Allison Thomson combed the scientific literature for every controlled study of soil respiration published since 1960. They found 439 studies altogether, three-quarters of which were published after the 1992 review. When they analyzed the cumulative data, Bond-Lamberty and Thomson found that soil respiration increased by about 0.1 percent every year since 1989, and was tightly tied to temperature.
"The global soil-respiration flux is changing," said Bond-Lamberty.
The data did contain an anomaly. While respiration tracked with temperature in temperate and tropical regions, there was a negative correlation in the Arctic, where sensitivity to warming is thought to be especially pronounced.
According to Bond-Lamberty, researchers might have a flawed understanding of how carbon cycling works in Arctic soil. Those studies might also have been technically flawed. Because there were many fewer studies conducted in the Arctic than elsewhere, the results may be prone to statistical aberrations.
Whatever the anomaly's explanation, that data was still included when global soil-respiration rates were calculated and the rise identified.
What's not clear from the analysis is whether soil-respiration rates have increased without actually affecting atmospheric balances of CO2, or if CO2 that would have remained earthbound is now being released.
Both possibilities may be true, wrote University of Aberdeen biologist Pete Smith and Fudan University ecologist Changming Fang in a commentary accompanying the analysis.
"Assessing the balance between increased soil carbon inputs through greater plant growth due to climate warming, and increased carbon losses through higher decomposition rates, should be a research priority," they wrote.
A small subset of studies in the review did try to answer that question by experimentally manipulating how much carbon entered test plots of soil. "That dataset is more tentative, but it does imply a feedback," said Bond-Lamberty.
The database used in the study is described in a paper published in February in Biogeosciences. All the data is publicly available.
Images: 1) Nicholas_T/Flickr. 2) Annual global soil respiration, total petagrams/Nature.
Citations: "Temperature-associated increases in the global soil respiration record." By Ben Bond-Lamberty & Allison Thomson. Nature, Vol. 464, No. 7288, March 25, 2010.
"A warm response by soils." By Pete Smith and Changming Fang. Nature, Vol. 464, No. 7288, March 25, 2010.
Posted: 25 Mar 2010 09:32 AM PDT
Chimpanzee culture is driven by its females, suggests a new analysis of six long-term chimp studies.
The number of cultural traits in each colony is linked to the number of females. How many males there are makes no difference.
"Our results suggest that females are the carriers of chimpanzee culture," wrote study co-authors Johan Lind and Patrik Lindenfors, both evolutionary biologists at Stockholm University's Center for the Study of Cultural Evolution.
Lind and Lindenfors' paper, published March 24 in Public Library of Science ONE, was prompted by two sets of observations. First, as becomes more evident with each passing month, chimpanzees possess complex learned behaviors that vary between colony and region. They have culture.
Second, the culture resides in the females. They use tools more frequently than males, and spend more time teaching tricks to their young. And while male chimpanzees tend to stay in the same colony, females will sometimes transfer. Culture would travel with them.
From this, Lind and Lindenfors reasoned that the driving force behind chimpanzee culture ought to be females. They pulled together data from six decades-long studies of chimpanzee colonies in the jungles of Central and West Africa. The data supported their hypothesis.
"The reported number of cultural traits in chimpanzee communities correlates with the number of females in chimpanzee communities, but not with the number of males," they wrote.
That's a different dynamic of cultural transmission than appears to have existed in early humans, where computer models suggest that population density was key. Once there were enough people, cultural evolution accelerated rapidly. After a 2 million-year-long Stone Age, civilization flourished in a comparative handful of millennia.
When trying to understand how chimpanzee culture works, "Some of the general theory behind human cultural evolution cannot strictly be applied to chimpanzees," said Lind. Neither should chimpanzee dynamics be seen as an automatic window into our own past.
"The variation in sociality in now-living apes is phenomenal. We have monogamous gibbons, and then gorillas who live in harems. We have two species of chimpanzees, and their social structures are completely different," said Lind. "According to the best data, we're just as closely related to the bonobo. We could look at them and ask, why don't we have sex rather than kissing on the cheek? There's nothing default about chimpanzees."
An open question is how cumulative chimpanzee culture is, said Lind. Whereas human cultural innovations are "stacked," with innovations building on each other to produce ever-more-complex tools and behaviors, that doesn't seem to be the case with chimpanzees, at least not to a comparable degree way.
Maybe chimpanzees aren't capable of that, or haven't reached their own cultural tipping point, said Lind. Or perhaps we've started to study them too late, with human development having left only isolated pockets of chimpanzee culture.
"When we watch chimpanzees, we look at some scattered remains from previous, much larger populations," said Lind. "I just hope that those remaining spots where chimps can live today will remain."
Images: 1) Mark Fosh/Flickr. 2) Graph of female group size and cultural traits observed in six chimpanzee studies/PLoS ONE
Citation: "The Number of Cultural Traits Is Correlated with Female Group Size but Not with Male Group Size in Chimpanzee Communities." By Johan Lind and Patrik Lindenfors. PLoS ONE, Vol. 5 No. 3, March 24, 2010.
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