POSITIVELY CHARGED HUMIDITY
Scientists work to harness lightning for electricity
by Candace Lombardi / August 26, 2010
Nikola Tesla would be jealous. A group of chemists from the University of Campinas in Brazil presented research on Wednesday claiming they’ve figured out how electricity is formed and released in the atmosphere. Based on this knowledge, the team said it believes a device could be developed for extracting electrical charges from the atmosphere and using it for electricity. The team, led by Fernando Galembeck, says they discovered the process by simulating water vapor reactions in a laboratory with dust particles common to the atmosphere.
They found that silica becomes more negatively charged when high levels of water vapor are present in the air, in other words during high humidity. They also found that aluminum phosphate becomes more positively charged in high humidity. “This was clear evidence that water in the atmosphere can accumulate electrical charges and transfer them to other materials it comes into contact with. We are calling this ‘hygroelectricity,’ meaning ‘humidity electricity,'” Galembeck said in a statement. But the discovery, if true, goes against the commonly held theory among scientists such as the International Union of Pure and Applied Chemistry, that water is electroneutral–that it cannot store a charge. Galembeck, who is a member of the IUPAC, told New Scientist that he does not dispute the principle of electroneutrality in theory, but that he believes real-life substances like water have ion imbalances that can allow it to produce a charge.
The hygroelectricity discovery could lead to the invention of a device that is able to tap into all that energy. Akin to a solar panel, a hygroelectrical panel on a roof would capture atmospheric electricity that could then be transferred for a building’s energy use, according to the University of Capinas team. In addition to capturing electricity, such a device could also be used to drain the area around a building of its electrical charge, preventing the atmospheric discharge of electricity during storms–aka lightning. “We certainly have a long way to go. But the benefits in the long range of harnessing hygroelectricity could be substantial,” Galembeck said. The research was presented in Boston at the 240th National Meeting of the American Chemical Society.
Harness lightning for energy, thanks to high humidity?
by David Biello / Aug 26, 2010
Why do the roiling, black clouds of a thunderstorm produce lightning? Ben Franklin and others helped prove that such lightning was discharged electricity, but what generates that electricity in such prodigious quantities? After all, storms generate millions of lightning bolts around the globe every year—even volcanoes can get in on the act as the recent eruption of Eyjafjallajökull did when photographs captured bolts of blue in the ash cloud.
Perhaps surprisingly, scientists still debate how exactly lightning forms; theories range from colliding slush and ice particles in convective clouds to, more speculatively, a rain of charged solar particles seeding the skies with electrical charge. Or perhaps the uncertainty about lightning formation is not surprising, given all that remains unknown about clouds and the perils of studying a storm—an electrical discharge can deliver millions of joules of energy in milliseconds.
But Brazilian researchers claim that their lab experiments imply that the water droplets that make up such storms can carry charge—an overturning of decades of scientific understanding that such water droplets must be electrically neutral. Specifically, chemists led by Fernando Galembeck of the University of Campinas found that when electrically isolated metals were exposed to high humidity—lots and lots of tiny water droplets known as vapor—the metals gained a small negative charge.
The same holds true for many other metals, according to Galembeck’s presentation at the American Chemical Society meeting in Boston on August 25—a phenomenon they’ve dubbed hygroelectricity, or humid electricity. “My colleagues and I found that common metals—aluminum, stainless steel and others—acquire charge when they are electrically isolated and exposed to humid air,” he says. “This is an extension to previously published results showing that insulators acquire charge under humid air. Thus, air is a charge reservoir.” The finding would seem to confirm anecdotes from the 19th century of workers literally shocked—rather than scalded—by steam. And it might explain how enough charge builds up for lightning, Galembeck argues.
The scientists envision devices to harness this charge out of thick (with water vapor) air—a metal piece, like a lightning rod, connected to one pole of a capacitor, a device for separating and storing electric charge. The other pole of the capacitor is grounded. Expose the metal to high humidity (perhaps within a shielded box) and harvest voltage. “If this could be done safely, it would allow us to have better control of thunderstorms,” Galembeck says, envisioning a renewable energy source from the humid air of the tropics and mid-latitudes.
Unfortunately, the finding violates the principle of electric neutrality, in which the differently charged molecules of an electrolyte like water cancel out. And although geophysicists and other atmospheric scientists may not know all the details of how lightning forms, they do have a general sense, and hygroelectricity seems to ignore what is largely understood. “It is utter nonsense,” says atmospheric physicist William Beasley of the University of Oklahoma, a lightning researcher. “All seriously considered mechanisms for electrification of thunderstorms that can lead to the kind of electric fields that are required for lightning involve convection and rebounding collisions between graupel [a slush ball] and ice particles in convective storms.”
Similar efforts to capture the electricity in a lightning bolt have failed, most recently, Alternate Energy Holdings’s would-be lightning capture tower outside Houston. The wired tower never worked. “This concept has been disproven many times over,” Beasley notes. What’s more, the amount of energy in a lightning bolt—never mind its crackling electric grandeur—is but a fraction of the amount of energy required to run even one 100-watt lightbulb, which uses 100 joules every second, for a day. But taming lightning is a prospect that has tempted experimenters since at least the Olympian thunderbolts of Zeus. Of course, the vast majority of the energy is in the storm itself—hurricanes, for example, have the heat energy of 10,000 nuclear bombs. Capturing that energy might prove frazzling.
Can we grab electricity from muggy ai?
by Colin Barras / 26 August 2010
Every cloud has a silver lining: wet weather could soon be harnessed as a power source, if a team of chemists in Brazil is to be believed. In 1840, workers in Newcastle upon Tyne, UK, reported painful electric shocks when they came into close contact with steam leaking from factory boilers. Both Michael Faraday and Alessandro Volta puzzled over the mysterious phenomenon, dubbed steam electricity, but it was ultimately forgotten without being fully understood.
Fernando Galembeck at the University of Campinas in São Paulo, Brazil, is one of a small number of researchers who thinks there is a simple explanation, but it involves accepting that water can store charge – a controversial idea that violates the principle of electroneutrality. This principle – which states that the negatively and positively charged particles in an electrolyte cancel each other out – is widely accepted by chemists, including the International Union of Pure and Applied Chemistry (IUPAC). “I don’t dispute the IUPAC statement for the principle of electroneutrality,” says Galembeck. “But it is seldom applicable to real substances,” he says, because they frequently show ion imbalances, which produce a measurable charge.
His team electrically isolated chrome-plated brass tubes and then increased the humidity of the surrounding atmosphere. Once the relative humidity reached 90 per cent, the uncharged tube gained a small but detectable negative charge of 300 microcoulombs per square metre – equating to a capacity millions of times smaller than that of an AA battery.
The Victorian workers would have had to have been particularly sensitive souls to complain of such a shock, but Galembeck thinks his study shows steam electricity may be a credible phenomenon. He thinks the charge builds up because of a reaction between the chrome oxide layer that forms on the surface of the tube and the water in the atmosphere. As the relative humidity rises, more water condenses onto the tube’s surface. Hydrogen ions in the water react with the chrome oxide, leading to an ion imbalance that imparts excess charge onto the isolated metal.
The work finds favour with Gerald Pollack at the University of Washington in Seattle. Last year he suggested that pure water could store charge and behave much like a battery, after finding that passing a current between two submerged electrodes created a pH gradient in the water that persisted for an hour once the current had been switched off. He says this is evidence that the water stores areas of positive and negative charge, but the experiment led to a lively debate in the pages of the journal Langmuir over whether the results really violated the principle of electroneutrality or whether there were salt impurities in the water that led it to behave like a conventional electrochemical cell. Pollack calls the Campinas team’s work “interesting”. “It opens the door to many new possibilities,” he says.
Power from air
Galembeck thinks those possibilities include harnessing atmospheric humidity as a renewable power source, as light is converted to electricity in solar panels. “My work is currently targeted to verify this possibility and to explore it,” he says. However, he acknowledges that most researchers remain to be convinced that what he calls “hygroelectricity” will ever get off the ground.
Allen Bard at the University of Texas falls within that majority. “In general I think that it is true that our understanding of electrostatic phenomena and charging at solid/gas interfaces is incomplete,” he says. “I am, however, very sceptical about these phenomena being harnessed as a power source. The amounts of charge and power involved are very small.”
References: Galembeck presents his work at a national meeting of the American Chemical Society in Boston this week; it was previously published in Langmuir, DOI: 10.1021/la102494k. Pollack’s work was published in Langmuir, DOI: 10.1021/la802430k; the resulting debate in the journal can be followed here, here, and here.
ENERGY in the AIR
Electricity collected from the air could become the newest alternative energy source
Aug. 25, 2010
Imagine devices that capture electricity from the air ― much like solar cells capture sunlight ― and using them to light a house or recharge an electric car. Imagine using similar panels on the rooftops of buildings to prevent lightning before it forms. Strange as it may sound, scientists already are in the early stages of developing such devices, according to a report presented here today at the 240th National Meeting of the American Chemical Society (ACS). “Our research could pave the way for turning electricity from the atmosphere into an alternative energy source for the future,” said study leader Fernando Galembeck, Ph.D. His research may help explain a 200-year-old scientific riddle about how electricity is produced and discharged in the atmosphere. “Just as solar energy could free some households from paying electric bills, this promising new energy source could have a similar effect,” he maintained. “If we know how electricity builds up and spreads in the atmosphere, we can also prevent death and damage caused by lightning strikes,” Galembeck said, noting that lightning causes thousands of deaths and injuries worldwide and millions of dollars in property damage.
The notion of harnessing the power of electricity formed naturally has tantalized scientists for centuries. They noticed that sparks of static electricity formed as steam escaped from boilers. Workers who touched the steam even got painful electrical shocks. Famed inventor Nikola Tesla, for example, was among those who dreamed of capturing and using electricity from the air. It’s the electricity formed, for instance, when water vapor collects on microscopic particles of dust and other material in the air. But until now, scientists lacked adequate knowledge about the processes involved in formation and release of electricity from water in the atmosphere, Galembeck said. He is with the University of Campinas in Campinas, SP, Brazil.
Scientists once believed that water droplets in the atmosphere were electrically neutral, and remained so even after coming into contact with the electrical charges on dust particles and droplets of other liquids. But new evidence suggested that water in the atmosphere really does pick up an electrical charge. Galembeck and colleagues confirmed that idea, using laboratory experiments that simulated water’s contact with dust particles in the air. They used tiny particles of silica and aluminum phosphate, both common airborne substances, showing that silica became more negatively charged in the presence of high humidity and aluminum phosphate became more positively charged. High humidity means high levels of water vapor in the air ― the vapor that condenses and becomes visible as “fog” on windows of air-conditioned cars and buildings on steamy summer days. “This was clear evidence that water in the atmosphere can accumulate electrical charges and transfer them to other materials it comes into contact with,” Galembeck explained. “We are calling this ‘hygroelectricity’, meaning ‘humidity electricity’.”
In the future, he added, it may be possible to develop collectors, similar to the solar cells that collect the sun to produce electricity, to capture hygroelectricity and route it to homes and businesses. Just as solar cells work best in sunny areas of the world, hygroelectrical panels would work more efficiently in areas with high humidity, such as the northeastern and southeastern United States and the humid tropics. Galembeck said that a similar approach might help prevent lightening from forming and striking. He envisioned placing hygroelectrical panels on top of buildings in regions that experience frequent thunderstorms. The panels would drain electricity out of the air, and prevent the building of electrical charge that is released in lightning. His research group already is testing metals to identify those with the greatest potential for use in capturing atmospheric electricity and preventing lightning strikes. “These are fascinating ideas that new studies by ourselves and by other scientific teams suggest are now possible,” Galembeck said. “We certainly have a long way to go. But the benefits in the long range of harnessing hygroelectricity could be substantial.”
email : fernagal [at] igm.unicamp [dot] br
email : ghp [at] u.washington [dot] edu
SEE ALSO : POLYWATER BATTERIES
Dr. Gerald Pollack’s views on water have been called revolutionary. He attests that, despite what Mr. Wizard may have taught you, there are actually four phases of water: solid, liquid, vapor and gel. This fourth phase, Pollack says, may in fact be the most important of all. “If you want to understand what happens in any system – be it biological, or physical, or chemical, or oceanographic, or atmospheric, or whatever – it doesn’t matter, anything involving water, you really have to know the behavior of this special kind of gel-like water, which dominates.”
Pollack’s water studies have led to amazing possibilities: that water acts as a battery, that this battery may recharge in a way resembling photosynthesis, that these water batteries could be harnessed to produce electricity. He discusses these ideas in a lecture now playing on UWTV: “Water, Energy and Life: Fresh Views From the Water’s Edge.” Yet the search for these fresh views has not been without struggle. “Before I became controversial, I almost never had a problem; I had large amounts of funding,” Pollack, a UW professor of bioengineering, explained. “The more controversial I became, the more difficult it’s been to get money. There were several really dry years. “And now it’s gotten better because I think people are beginning to recognize the importance of the work on water. So it’s improving, but it’s still not easy.”
The study of water has a long history of unpopularity, Pollack said. “Six or seven decades ago, water was a really interesting subject. A lot of people thought that water had a particular chemistry – that it interacted with other molecules and was really an important feature of any system that contained water. Then, research almost stopped 40 years ago. There were two scientific debacles that took place that made everybody highly skeptical of any kind of research on water.” The first of these concerned polywater. “Some findings seemed to imply that water acted as though it was a polymer; in other words, all the molecules would somehow join together into a polymer and create some really weird kinds of effects,” Pollack described. Eventually, these results – first presented by a Russian chemist – were discredited. “The nails were driven into the coffin of water research by another debacle that took place 20 years later, and that was the idea of water memory,” Pollack said. “The idea was that water molecules could have memory of other substances into which it had been in contact.”
A debate in the science journal Nature eventually moved public opinion against this theory as well. “So because of these two incidents, scientists absolutely stayed away from water because water research was treacherous,” Pollack said. “You could drown in your own water.” Yet, these murky waters were not enough to deter Pollack from the subject. He first broached the topic in his 2001 book “Cells, Gels and the Engines of Life.” “The book asserts, contrary to the textbook view, that water is the most important and central protagonist in all of life,” Pollack said. “There are so many realms of science where water is central. In order to understand how everything works, you need to know the properties of water.” As Pollack sought to understand water, his focus turned to a particular phase near hydrophilic surfaces that didn’t quite fit in. “The three phases of water that everybody knows about in the textbook just don’t do it. In fact, it’s a 100-year-old idea that there’s a fourth phase of water. This is not an original idea.” Though the concept of a liquid crystalline, or gel-like, phase of water has been around for some time, the generally accepted view is that this kind of water is only two or three molecular layers thick. “And what we found in our experiments is that it’s not two or three layers, but two or three million layers. In other words, it’s the dominant feature,” Pollack said.
With this revelation in hand, Pollack focused his attention on this mostly unstudied phase of water. He has since discovered much about its underestimated thickness, its capacity to create a charge, its connections to photosynthesis and its practical applications. The thickness of this gel-like water may explain why items of higher density than water – such as a coin – can float. Surface tension is at work, but it arises from this thick, gel-like surface layer. “Turns out that the thickness depends on the pH,” Pollack said. “If you increase the pH, we found that this region gets thicker. It also gets thicker with time. So if you wait long enough, and if you have the right conditions, and maybe enough light beating down on it, you could conceivably get a very thick layer. “If we come up with the right conditions, maybe it’s true that we can walk on water – if this region can be made thick enough.”
Biblical aspirations aside, the energy carried within this water and the water near it may be even more impressive. Dr. Pollack works in his lab to demonstrate some of the unusual properties of water. “This kind of water is negative, and the water beyond is positive. Negative, positive – you have a battery,” Pollack explained. “The question is, how is it used and might we capitalize on this kind of battery?” The key to understanding how this water battery works is learning how it is recharged. “You can’t just get something for nothing – there has to be energy that charges it,” Pollack said. “This puzzled us for several years, and finally we found the answer: it’s light. It was a real surprise. So if you take one of these surfaces next to water, and you see the battery right next to it, and you shine light on it, the battery gets stronger. It’s a very powerful effect.” This effect takes on entirely new possibilities when considered in terms of the water within our bodies. “I’m suggesting that you – inside your body – actually have these little batteries, and, remember, the batteries are fueled by light,” Pollack said. “Why don’t we photosynthesize? And the answer is, probably we do. It may not be the main mechanism for getting energy, but it certainly could be one of them. In some ways, we may be more like plants and bacteria than we really think.”
All of these innovative ideas may have practical applications as well. Water in its gel-like phase excludes solutes. “It’s actually pretty pure,” Pollack explained. “If you could collect this water right near the surface, it should be free of bacteria, for example, and maybe also viruses. So we’ve constructed a prototype device in the laboratory that shows excellent separation, on the order of 200 to 1. And we’re now trying to scale this up to practical quantities of water that could be filtered.” A second possibility is extracting electrical energy from this natural water battery. “We’ve so far been able to get only small amounts of electrical energy out, but we just started the project,” Pollack said. “If this process that we found is the same as photosynthesis, or the same principle, and I do think it may be, then it’s a pretty efficient system.”
Pollack and other researchers clearly have a long and complex challenge ahead as they seek to understand water in new ways. But you don’t have to know Pollack well to see that the challenge itself is part of the intrigue of pursuing such work. “I’m so compelled to continue our studies because they reveal so much and they answer so many questions – even already – questions that have remained unanswered for so long. For Pollack, finding answers is a way of life. “I dream this stuff,” he confessed. “It never leaves me. If I’m sitting on the plane, sitting on the toilet seat, standing in the shower, it’s on my mind always. “When I see something in nature that doesn’t seem right, or doesn’t seem explained yet, I just can’t stop thinking about it. Thinking about how it might work. I dwell on the problem. I never stop.”
email : nocera [at] mit [dot] edu
by David L. Chandler / May 14, 2010
Expanding on work published two years ago, MIT’s Daniel Nocera and his associates have found yet another formulation, based on inexpensive and widely available materials, that can efficiently catalyze the splitting of water molecules using electricity. This could ultimately form the basis for new storage systems that would allow buildings to be completely independent and self-sustaining in terms of energy: The systems would use energy from intermittent sources like sunlight or wind to create hydrogen fuel, which could then be used in fuel cells or other devices to produce electricity or transportation fuels as needed.
Nocera, the Henry Dreyfus Professor of Energy and Professor of Chemistry, says that solar energy is the only feasible long-term way of meeting the world’s ever-increasing needs for energy, and that storage technology will be the key enabling factor to make sunlight practical as a dominant source of energy. He has focused his research on the development of less-expensive, more-durable materials to use as the electrodes in devices that use electricity to separate the hydrogen and oxygen atoms in water molecules. By doing so, he aims to imitate the process of photosynthesis, by which plants harvest sunlight and convert the energy into chemical form.
Nocera pictures small-scale systems in which rooftop solar panels would provide electricity to a home, and any excess would go to an electrolyzer — a device for splitting water molecules — to produce hydrogen, which would be stored in tanks. When more energy was needed, the hydrogen would be fed to a fuel cell, where it would combine with oxygen from the air to form water, and generate electricity at the same time. An electrolyzer uses two different electrodes, one of which releases the oxygen atoms and the other the hydrogen atoms. Although it is the hydrogen that would provide a storable source of energy, it is the oxygen side that is more difficult, so that’s where he and many other research groups have concentrated their efforts. In a paper in Science in 2008, Nocera reported the discovery of a durable and low-cost material for the oxygen-producing electrode based on the element cobalt.
Now, in research being reported this week in the journal Proceedings of the National Academy of Science (PNAS), Nocera, along with postdoctoral researcher Mircea Dincă and graduate student Yogesh Surendranath, report the discovery of yet another material that can also efficiently and sustainably function as the oxygen-producing electrode. This time the material is nickel borate, made from materials that are even more abundant and inexpensive than the earlier find. Even more significantly, Nocera says, the new finding shows that the original compound was not a unique, anomalous material, and suggests that there may be a whole family of such compounds that researchers can study in search of one that has the best combination of characteristics to provide a widespread, long-term energy-storage technology. “Sometimes if you do one thing, and only do it once,” Nocera says, “you don’t know — is it extraordinary or unusual, or can it be commonplace?” In this case, the new material “keeps all the requirements of being cheap and easy to manufacture” that were found in the cobalt-based electrode, he says, but “with a different metal that’s even cheaper than cobalt.” The work was funded by the National Science Foundation and the Chesonis Family Foundation.
But the research is still in an early stage. “This is a door opener,” Nocera says. “Now, we know what works in terms of chemistry. One of the important next things will be to continue to tune the system, to make it go faster and better. This puts us on a fast technological path.” While the two compounds discovered so far work well, he says, he is convinced that as they carry out further research even better compounds will come to light. “I don’t think we’ve found the silver bullet yet,” he says. Already, as the research has continued, Nocera and his team have increased the rate of production from these catalysts a hundredfold from the level they initially reported two years ago.
John Turner, a research fellow at the National Renewable Energy Laboratory in Colorado, calls this a nice result, but says that commercial electrolyzers already exist that have better performance than these new laboratory versions. “The question then is under what circumstances would this system provide some advantage over the existing commercial systems,” he says. For large-scale deployment of solar fuel-producing systems, he says, “the big commercial electrolyzers use concentrated alkali for their electrolyte, which is OK in an industrial setting were engineers know how to handle the stuff safely; but when we are talking about thousands of square miles of solar water-splitting arrays, and individual homeowners, then an alternative electrolyte like this benign borate solution may be more viable.” The original discovery has already led to the creation of a company, called Sun Catalytix, that aims to commercialize the system in the next two years. And his research program was recently awarded a major grant from the U.S. Department of Energy’s Advanced Research Projects Agency.
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