Updates on Alternative Energy Sources, Part 5: Wind
March 17, 2010
This is the fifth in a series of posts on alternative energy sources using as a starting point an article by Michael Totty [“The Long Road to an Alternative-Energy Future,” Wall Street Journal, 22 February 2010]. The topic to which Totty turns next is wind [“The Long Road: Wind,” Wall Street Journal, 22 February 2010]. Totty writes:
“THE TECHNOLOGY: Wind power is one of the fastest-growing alternative energy sources in the world—a low-carbon, renewable source of electricity that can deliver millions of watts of relatively low-cost power.
CURRENT STATUS: In the U.S., wind produced about 73 billion kilowatt-hours of electricity last year, about 2% of total generation and enough to power about 13 million homes. Industry capacity rose nearly 10,000 megawatts, or 39%, last year to a total of about 35,000 megawatts.”
Up to this point, Totty has gone to great lengths to explain that widespread implementation of the alternative energy sources he has discussed is over the horizon, if not over the rainbow. He’s a lot more optimistic about wind. He concludes:
“WHY IT’S GOING TO TAKE SO LONG: It may not. The U.S. Energy Department laid out a scenario for how wind could meet 20% of total electricity demand by 2030—about 300 gigawatts—displacing half of natural gas-powered and 18% of coal-fired generation. But a recent report by the National Renewable Energy Laboratory, or NREL, found that the Eastern U.S., which isn’t blessed with substantial onshore wind resources, could hit the 20% target by 2024. Still, reaching that goal is going to take significant investments in new transmission lines, especially in a transmission ‘superhighway’ to carry electricity from parts of the country with lots of wind to places where demand is highest. The NREL study estimates the price tag could be as high as $93 billion. Local opposition to transmission lines can also present a challenge, especially when lines have to cross states to carry power to a neighbor. It also may require significant additions of offshore wind power, which the Energy Department predicts could deliver about 17% of its projected 2030 total. Offshore wind generation promises more reliable power, and because it’s closer to East Coast population centers, less transmission is needed. But offshore generation is about twice as expensive as onshore wind power and faces opposition from coastal property owners. Power from the first of a handful of proposed offshore wind projects is expected by 2012.”
Upgrading transmission lines, especially in America, is perhaps the greatest challenge for proponents of wind power. Transmission lines are a kind of common good that utility companies need but are hesitant to invest in because other companies may gain access to those lines without having contributed to their construction. For that reason, “The U.S. Energy Dept., among others, would like to build the equivalent of an interstate highway system for transporting electricity around the country—if it could only find a budget for it. The part of the project targeting wind alone would cost about $20 billion” [“Wind: The Power. The Promise. The Business,” by Steve Hamm, BusinessWeek, 7 July 08 print issue]. Hamm continues: “Another hang-up: Major new transmission projects take up to four years to get approval from municipalities and state utility authorities.” The lack of transmission lines is one of the primary reasons that oil magnet T. Boone Pickens abandoned his plans last year to build the world’s largest wind farm in the Texas panhandle. Another challenge that Totty didn’t mention is the rise of NIMBYs (not in my backyard protestors). NIMBYs have been particularly active in protesting offshore wind farms like the one proposed off of Nantucket Island in Massachusetts.
As the NIMBYs are happy to explain, wind turbines used to generate electricity are big and noisy. In order to create large amounts of electricity, they have to be big. Researchers, however, are trying to make them quieter [“Rubber trailing edge flaps could result in quieter, more productive wind farms,” by Ben Coxworth, Gizmag, 28 February 2010]. Coxworth reports:
“If you’ve ever seen a commercial-scale wind turbine in real life, then you’ll know that they’re huge – a single blade can be as long as 60 meters (197 feet). Researchers from Denmark’s Risoe DTU National Laboratory for Sustainable Energy tell us that such blades can flex by up to six meters (20 feet) when subjected to strong wind gusts. Worse yet, that load is often not evenly distributed along the length of the blade, so it doesn’t flex evenly. Fortunately, the researchers are working on addressing this problem, by attaching flexible flaps to the trailing edges of the blades. These flaps come in the form of silicone rubber strips, which run the length of the entire blade. The result, we’re told, will be quieter, higher-output turbines. … Wind tunnel tests showed that different curvatures of the flaps could compensate for different intensities and directions of wind, but how do you continuously adjust those curvatures? The Risoe team put two sensors on the front of their blade section, which measured wind speed and direction. The data from those sensors was fed into a pneumatic system inside the blade, which changed the shape of the flap by pumping air in or out of it. Presumably on an entire blade, there would be sensors all the way down the forward edge, and the trailing edge strip would be divided into cells that could each assume different curvatures as dictated.”
Research on wind turbine blades has motivated scientists to look to nature for answers. For example, Dr. Emile H. Ishida, a professor at Tohoku University’s Graduate School of Environmental Studies, has created a design for fan-blades based on the uneven shape of dragonfly wings [“Scientists raid mother nature’s cupboard,” by Jonathan Soble, Financial Times, 10 December 2009]. Soble explains:
“A cross-section of a dragonfly’s wing shows its paper-thin surface to be saw-tooth shaped like a ruffled potato crisp. This structure, Mr Ishida says, produces tiny whirling vortexes in the creases, which push air back, generate lift and give the wings ‘virtual’ volume without adding bulk or weight. Mr Ishida has incorporated the shape in wings he has designed for small, agile gliders – potential forerunners of ultra-lightweight aircraft. But the design may be even more useful in wind turbines, an increasingly popular yet fallible means of generating electricity. Prototype turbines built by Mr Ishida, using dragonfly-wing blades, keep on spinning even when winds drop to near-undetectable levels. ‘With this kind of efficiency it becomes feasible for every household to generate part of its own electricity with a small wind turbine,’ Mr Ishida says. ‘It changes the basic dynamics of power distribution.'”
Another researcher that has drawn from nature to develop better turbine blades is Dr. Frank E. Fish [“Bumpy whale fins set to spark a revolution in aerodynamics,” by Loz Blain, Gizmag, 20 March 2008]. Blain explains:
“The random-looking bumps on the humpback whale’s flippers have just inspired a breakthrough in aerodynamic design that seems likely to dramatically increase the efficiency and performance of wind turbines, fans, flippers and even wings and airfoils. WhalePower’s tubercle technology seems like nothing less than a revolution in fluid dynamics. … Current theory would state that the leading edge of a fin, fan or turbine blade should be absolutely straight and smooth for best effect – a ‘fact’ that has been taken for granted for decades. But the more Fish studied the odd leading-edge bumps, or Tubercles, the more it became apparent that evolution’s work on the fin was far ahead of man’s best efforts. Airfoils fitted with tubercle bumps showed much higher lift efficiency and greater stall resistance than identical airfoils without them. Turbines fitted with tubercles to the leading edges of each blade are able to produce more power at low fluid speeds, are quieter, and perform much better in turbulent fluid streams. … Wind power generation turbines stand to gain greatly from the discovery; because they can be used at a greater pitch angle with much less drag and much less tendency to stall, they allow turbines to continue generating power at wind speeds that are much too slow for traditionally shaped turbines to operate safely in. Importantly for the turbine market, tubercles can be retrofitted to the leading edge of conventional blades. Real world performance is proving very impressive, leading several major wind farm manufacturers to seek retrofit kits for their existing designs.”
Efforts to help turbines create electricity, even in low wind conditions, could significantly increase the number of places where wind turbines could be constructed. Some new designs for wind turbines are marked departures from traditional designs [“A Juiced-Up Wind Turbine,” by Adam Aston, BusinessWeek, 9 November 2009 print issue]. Aston reports:
“Using features from jet engines, FloDesign Wind Turbine created a compact prototype three times more efficient at turning wind into electricity than today’s three-bladed windmills. Two concentric hoops channel air into patterns that create spinning vortexes—like miniature tornadoes—as air exits past the blades. This dramatically boosts air flow. Proponents say the design could transform the wind business in several respects. For example, today’s towering turbines require a caravan of tractor trailers to transport them. FloDesign’s model fits on a single rig. What’s more, the new design can produce energy at lower wind speeds and in more volatile gusts, making it a natural for spots—such as cities and beaches—that are inhospitable to bigger rigs.”
Although wind farms are likely to be the largest source of electricity produced by air currents, one of my favorite innovations is a wind turbine that fits atop a house’s chimney and produces electricity for household use [“Secret Energy Turbine: rooftop wind power in stealth mode,” by Ben Coxworth, Gizmag, 23 February 2010]. Coxworth describes the system:
“Few people would argue that having a rooftop wind turbine could help offset your power bills. Your neighbors, however, might not appreciate the sight of a windmill on your roof, nor would they like the sound of its blades whistling through the air. Don’t give up on the idea yet, though, because British inventor Rupert Sweet-Escott has come up with a product that he claims addresses those problems. His Secret Energy Turbine (SET) looks like an ordinary chimney stack and is boasts almost completely silent operation. The SET has vertically-mounted blades, and two opposing magnets to help keep it spinning. As the blades catch the wind and start to spin, they form an airfoil by means of boundary layers. These boundary layers are the same as the layer of air that moves over an airplane’s wings, and the result is a faster-turning turbine. The uneven current it generates gets organized by an electronic load controller, then fed into one or more battery packs for storage. From there, a sine wave inverter converts it to a regular household voltage, and you can use it for whatever you want.”
Coxworth reports that the system comes in several sizes which produce various amounts of electricity depending on available winds. The system doesn’t produce enough electricity to run everything day and night in a modern wired household, but it produces enough to significantly reduce the amount of electricity that needs to be drawn from the grid. The chimney wind turbine doesn’t come cheap, however. According to Coxworth, “Prices range from the equivalent of $US1,145 for the 300mm model, to $1,716 for the 500mm. You will also need a load controller, one or more batteries, and the services of an electrician. Of course with something like this, it isn’t just about saving money. If the figures are to be believed, a SET could definitely lower your carbon footprint.”
The most recent challenge to wind power comes from Congress where four democratic senators want subsidies to wind farms and alternative energy projects to be halted. The reason, they say, is that too much of the money is heading out of the country [“Four Democratic senators aim to halt stimulus wind project,” by Dan Eggen, Washington Post, 4 March 2010]. Eggen reports that supporters of wind power were quick to react:
“The American Wind Energy Association said that for the first $1 billion spent on the program, 53 percent of the value of wind turbines — and 63 percent of other equipment on wind farms — came from the United States. The trade group also estimated that 50,000 jobs would be lost if the grants were halted. Energy Department spokeswoman Stephanie Mueller said a moratorium ‘would cause immediate layoffs of American workers’ at U.S. manufacturing plants, including some in the home states of the complaining senators.”
Over the long haul, subsidies are not the answer to energy security. To be sustainable alternative energy sources must prove themselves to be competitive and profitable on their own. The best thing that government can do is build the transmission lines that will be needed to take advantage of new sources of electricity. Obviously, wind is not the ultimate solution to weaning countries off of fossil fuel-powered plants. But wind power is poised to play a significant role in meeting power generation requirements in the future. Despite the challenges discussed above and reduced investment funds due to the Great Recession, wind power capacity in the United States increased by 39% in 2009 [“Wind Power Grows 39% for the Year,” by Jad Mouawad, New York Times, 26 January 2010]. However, much of that capacity increase, Mouawad reports, was actually the result of projects begun before the recession hit in 2008. Most analysts predict that the wind power sector will continue to have a bright future.