Tomorrow's utility technology may be revolutionized at the molecular level.
Revolutionary changes have swept through the utility industry more than once. Although the industry often receives criticism for being slow to adapt, the fact is that utilities are continually building and rebuilding their systems and strategies around changing conditions. AAAAA AASuccess in utility planning often hinges on big things-like market restructuring or an upheaval on Wall Street. It can also depend on little things-like a piece of software or a metering device. And sometimes it depends on tiny things-in the case of nanotechnology, things that didn't exist yesterday, but that just might spawn a revolution tomorrow.
The science of nanotechnology is no longer restricted to ivory-tower research labs. Nanostructures have already entered the marketplace, on electronics store shelves and even in the fabric of stain-resistant khakis. And now, nanotechnology is poised to bring radical new products to the utility industry-products that could revolutionize the way power is generated and delivered.
If the term "revolution" seems like hype, consider how the transmission system might change if power lines a centimeter in diameter could conduct a terawatt of power with virtually no resistance. Consider how the economics of distributed generation might change if fuel cell prices fell by an order of magnitude, and hydrogen could be produced cheaply on site?
Or what if the cost of solar cells fell by 98 percent? How might that affect power demand in the sun belt?
While most nanotechnology concepts are still in the lab, many are moving quickly toward commercialization. Solar-cell manufacturers, for example, are already designing factories that could begin spinning out next-generation photovoltaic (PV) materials within just a few years.
Given the technology's rapid progress, utilities should carefully consider its implications for their future business strategies. In that context, Fortnightly presents a brief tutorial on nanotechnology and the promise it holds for the industry.
Small Science
"Nanotechnology is the art and science of making stuff that does stuff on a nanometer scale," says Dr. Richard Smalley, whose discovery of the "buckyball," a new form of carbon (carbon-60), earned him the 1996 Nobel Prize in chemistry. That work led to the development of carbon nanotubes, cylindrical molecules with mechanical and electrical properties that would challenge the imagination of even the buckyball's namesake genius, the late Buckminster Fuller. These buckytubes boast a tensile strength far greater than steel and surpass the electrical conductivity of copper or silicon, but at one-sixth copper's weight.
Such facts attract plenty of headlines-not to mention hype. But Smalley says nanotechnology isn't really a new science; rather, it's an increasing ability on the part of chemists, physicists, and others in the hard sciences to manipulate materials at an atomic level.
He cites as one example modern engineered polymers like polypropylene, Kevlar, and block polymers. "These are highly engineered to do what they do. They are what they are because of putting atoms exactly where you want them to be," he says.
Closer to home, Smalley says high-temperature superconductors are an example of nanotechnology. "The supercurrent does what it does because of precise layering of atoms and composition. If you change it very much, it doesn't work as well."
Recall that just a few years ago high-temperature superconductors were the stuff of science fiction, along with cold fusion and the space elevator. While nanotechnology doesn't offer much in terms of cold fusion (or does it?), it just might revolutionize the world's energy industries in the 21st century-beginning today.
A Tiny Wire Into A Big Future
Carbon as a conductor? Engineers normally wouldn't consider it a candidate. Indeed, graphite, a common form of carbon, conducts electricity roughly 10100 times worse than copper. But Dr. Richard Smalley, who shared the 1996 Nobel Prize in Chemistry, believes his discovery of carbon-60 will eventually lead to carbon wires that can conduct electricity without meaningful resistance-and weigh less than half of traditional metal conductors.
If he can figure out how to spin a long wire composed of a particular type of the carbon nanotube he now produces, Smalley could have an impact on the electricity business that would be profound, to put it mildly.
A Light Pipe for Electrons
In essence, what Smalley hopes to do is spin a wire composed of a particular type of buckytube. A buckytube, which is a single carbon atom with a long, cylindrical shape, comes by its odd name from Smalley's initial discovery of carbon-60, which under a scanning tunneling microscope looks like the geodesic dome invented by Richard Buckminster Fuller. Smalley called this new carbon atom a buckyball, in honor of Fuller.
Both buckyballs and buckytubes are one nanometer wide-a billionth of a meter. That's just a little smaller than the diameter of a DNA double helix strand. What Smalley and others have discovered is that size really does matter; as physical materials approach a few nanometers in width, they start to behave very differently than they do in their larger, typical forms.
For example, carbon is normally a terrible conductor of electricity. But in nanoscale, that truism changes radically. "These little carbon tubes have an unparalleled ability to conduct electricity," Smalley says. "Plus, they have this really tricky, sexy aspect that normal mechanisms of resistance are just gone." He says electrons traveling down an armchair tube, a particular type and shape of buckytube, have only one way they can proceed, and those electrons encounter almost no mechanisms of resistance.
In contrast, copper and aluminum, two of the more common electrical conductors, do produce resistance. Electrons travel a few nanometers along copper or aluminum wire, meet the end of their path, and consequently "get kicked," as Smalley puts it, to the next available pathway. Of course, this deflection causes energy loss, thereby producing vibrations, i.e., heat. So the electrons traveling along a typical conducting material lose momentum to heat.
In an armchair buckytube, Smalley says, deflection is gone-the only thing electrons can do is move along the path of the tube. While not a superconductor, a strand of armchair tube wire would lack most types of resistance seen in metal conductors. Smalley calls this wire, which only exists in theory right now, a quantum wire. As he describes it, "This is a light pipe for electrons."
Smalley and other scientists have demonstrated in the lab the amount of current that can be pushed down one armchair tube: up to 20 microamps. Smalley believes that a cable of armchair tubes measuring one centimeter in diameter would have 1014 tubes in it. He calculates that centimeter-wide cable would conduct 10 terawatts of electricity. "It is just a huge, just incredible amount" of power, he says.
Spinning a Powerful Future
The only problem is, no one has been able to make such a cable. Yet.
But Smalley is hopeful. In his lab right now, he can spin a continuous fiber over a meter long-in fact, as many meters as he wants-of buckytubes. To make his fiber, he uses a method similar to that used in spinning Kevlar. But the fiber isn't composed solely, or even mostly, of the unique, highly conductive, armchair tubes. As a result, Smalley says current must hop from one tube to another, trillions of time, to traverse the fiber. The fiber's conductivity isn't very good, and that's putting it mildly.
Smalley predicts that if he and other scientists push hard in the next five years, an all-armchair tube nanowire will be produced. Considering that nanotubes were discovered only in 1991, his prediction may not be that far-fetched.
Even at his most optimistic, though, Smalley doesn't foresee the creation of nanowire hundreds of miles long. But the wire he hopes to make doesn't need to be all that long, he says.
To understand why, imagine that an electron is akin to a passenger on a train from Houston to Dallas, and the train and track it travels on is the equivalent of a buckytube. No one track goes all the way to Dallas, but trains on adjacent tracks will get the passenger to Dallas. Under normal circumstances, using copper as the train and track, the electron passenger would have to disembark and switch trains and tracks numerous times, possibly miss connections and have to wait, all of which would slow down the overall trip. An electron traveling along a buckytube, on the other hand, would simply disappear from one train and, in a blink, find itself traveling on another, at the same velocity. "This is what electrons and quantum particles really do in our universe," Smalley points out.
This phenomenon, which Smalley refers to as resonant quantum tunneling, would occur because the adjacent buckytube would be precisely identical atomically. As a result, the buckytubes seek out contact with each other, for tens of microns-which, in a nanoscale world, means 10,000 diameters of an armchair tube, and therefore plenty of opportunity for quantum tunneling by electrons.
Smalley's resonant quantum tunneling, like the power load limits of nanowire, is still theoretical. He freely admits that no one has verified the tunneling effect in even two adjacent tubes, let alone six or more in a fiber.
But if he or other scientists can pull it off, the implications are stunning for the grid.
A Reason to Re-String the Grid
Smalley thinks there is a high likelihood that when an armchair nanowire is made, it will have conductivity similar to copper. Even if the fiber is only half as conductive as carbon, he says, the one thing he knows for sure is what it will weigh: one-sixth the density of copper.
"If we can make [such a fiber] cheaply, it would be the logical replacement for every high-voltage transmission line in the world," Smalley says. He points out that most high-volatage lines now are aluminum, not because it's cheaper or more conductive than copper, but because of its lighter weight.
With an armchair nanowire, Smalley says, transmission lines could be much bigger in diameter and could take a larger amount of current through the same right-of-way. "That would be enough to make you re-string your cables," he notes in a bit of understatement. In addition, he thinks that his armchair nanowire would probably be good enough for use in AC settings. The cable could be insulated and grounded, and still have plenty of strength/weight ratio. And there would be no hum in such a wire, since there would be little resistance. "You wouldn't have hum, corona, RF losses, or worries about radiation fields in power lines," Smalley says.
Yet even if the technology can be proven in the lab, there remains the necessity to make the process work commercially. Smalley believes the cost cannot exceed $5/lb. for armchair nanowire, if it is to work commercially. He believes that goal is possible. Some types of nanofibers are being produced now commercially, at a cost of $1,000 to $100/lb. Those tubes come in a range of diameters, types, and lengths, but as Smalley points out, "it a start."
While Smalley is confident that an economical process for producing armchair tubes will be developed, he isn't yet chasing industry money. "Until we can get the first length made, it's premature for industry to invest," he says bluntly.
Yet if and when he does make a length of armchair nanowire, don't be surprised to see the world beating a path to Richard Smalley's door.
Cheap PVs for All
Historically, solar-electric cells, a.k.a. photovoltaics (PV), have played a diminutive role in supplying the world's electricity. The reason, of course, is cost. A watt of PV capacity costs about $90, compared with $5 for a kilowatt of diesel-engine capacity.
Nanotechnology, however, might be changing all of that.
"Our goal is to produce PV materials for less than $1 per watt," says Russell Gaudiana, Ph.D., vice president of research and development for Konarka Inc. in Lowell, Mass. "We have demonstrated every part of the process, and we have the technology in our hands to do it."
Nanotechnology is on the verge of revolutionizing the way PV materials are manufactured-eliminating the need for slow and costly vacuum deposition, and reducing costs by an order of magnitude or more.
"What nanotechnology provides is processability," says Stephen Empedocles, Ph.D., vice president of business development for Nanosys Inc. in Palo Alto, Calif. "We've changed the form factor of the inorganic material so it can be processed like a liquid."
The concepts and techniques vary from company to company, but essentially the idea is to produce photo-reactive materials-made of either organic or inorganic elements-that can be essentially "painted" onto a substrate. This should make it possible to produce long sheets of PV material in a roll-to-roll manufacturing process, running at high speeds in a normal atmosphere. This would not only boost the efficiency of production, but it would also dramatically reduce the cost of building PV-manufacturing factories-another barrier to today's PV technology.
Finally, these new PV materials are expected to be more flexible and durable than the rigid, breakable glass substrates of today's PV cells. This and other design factors might open up a whole new world for PV applications-from residential roofing systems to military uniforms.
These ideas might seem like the stuff of science fiction, but major companies expect to see real profit flowing from them in the not-too-distant future. For example:
- In late 2002, Matsushita Electric Works and Nanosys signed a contract to jointly develop building materials with integrated nano-PV cells. Matsushita-parent company of Panasonic-expects to begin selling such products in 2007.
- Both Nanosys and Konarka have formed relationships with defense contractor SAIC to develop military and other applications for their PV technologies. Moreover, this summer the U.S. Army provided funding support for Konarka's development of flexible, field-ready PV systems-possibly even uniforms with PV nanofibers woven into the fabric.
- In late September 2003, Electricité de France signed a cooperation agreement with Konarka to develop and launch the company's PV products "in a variety of form factors for commercial, industrial, government and consumer applications."
These and other developments suggest that within a few years, mass-production facilities will begin spinning out miles and miles of inexpensive PV materials. If that happens, PV could assume a much bigger role in the power industry-possibly even becoming a viable option for distributed generation applications.
Getting to that point, however, requires companies to finish commercializing their technology. Demonstrating the durability of a PV system, for example, is a key step. Researchers in Europe have tested the technology on which Konarka's products are based, and they found it should deliver at least a 10-year service life in the field. Konarka is testing its own application of the technology, and so far the results are equally promising.
"The ultimate test is to put it up on the roof and let Mother Nature do her thing," Gaudiana says. "We haven't done that yet, but we are encouraged by the results so far."
Fuel Cell Future
Fuel cells are among the most promising technologies for the future of power generation. Today, however, fuel cells suffer from high capital costs, high operating costs and constraints on fuel supply and storage.
Nanotechnology researchers, however, are developing solutions to these nagging problems. Researchers at the Georgia Institute of Technology, for example, are focused on the fuel end of the fuel-cell challenge.
Scientists have long known that oxides of certain rare-earth elements (cerium, terbium and praseodymium, to be precise) can produce hydrogen from water vapor and methane in continuous inhale and exhale cycles-cycles that Georgia Tech researchers call "oxygen pumping." Theoretically, this principle could yield technology for small-scale hydrogen production, which would address the fuel transportation and storage issues that now constrain fuel cells' commercial viability.
The Georgia Tech studies are focused on improving the efficiency of the oxygen-pumping process. "Our progress shows surprising improvements," says Dr. Zhong L. Wang, professor and director of Georgia Tech's Center for Nanoscience and Nanotechnology. By doping iron atoms into the oxides, Georgia Tech researchers have lowered the temperatures at which the rare-earth oxides produce hydrogen, from about 1,700 C to about 400 C. Additionally, researchers have developed techniques that eliminate the need for catalysts in the process-catalysts that are expensive and that degrade with use.
"Our next steps are to try to reduce the temperature more and improve efficiency," Wang says. "For large-scale production, we have to improve the pumping speed by a factor of five." Although this represents a significant research challenge, if successful it could give fuel cells a major boost.
An even bigger boost, however, could come from developments within the fuel cell itself. Toward this end, PlugPower Inc. in Latham, N.Y., together with Albany NanoTech, an R&D arm of the State University of New York, began developing nanostructures and materials for polymer electrolyte membrane fuel cells. The five-year project is aimed at achieving three main goals:
First, nanotechnology could improve the initial and long-term performance of fuel cells by optimizing the nano-scale structure of the electrodes. "If you put the particles down in a predetermined, structured way, you will get higher current densities, and over time the structure would probably be more stable too," says Dr. John Elter, PlugPower's vice president of research and system architecture.
Indeed, durability is the focus of the second goal. Today's membranes degrade with time and use, making fuel cells more costly to operate. "Nanotechnology is one path to improving stack life," Elter says. Specifically, a nano-structured electrode surface might prevent platinum particles from agglomerating and degrading the electrode's performance. "I hope we'll get an order of magnitude of improvement," Elter says. "But even if we double the stack life, that would also be very good."
The third goal involves reducing manufacturing costs by minimizing the amount of costly platinum required in an electrode. One approach involves using carbon nanotubes. "If you can get these tubes to stand on end on the membrane, you would have a much greater effective surface area, and the platinum loading would go down," Elter says.
Some nanotechnology researchers have reported staggering reductions in platinum loading-up to 98 percent reductions in some cases. Elter warns, however, that isolated lab results can be misleading, and more development will be required to achieve consistent, commercial-scale results. Still, he is optimistic about the prospects.
"There is a lot of promise in the literature, and tremendous momentum now," he says. "We should see a line of sight to an end game after a couple of years of research."
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