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Wind turbines at Altamont Pass Ca.

CHANGE IN THE WIND Scientific American Oct 97

Utilities are starting to offer renewable energy-for a price

Most utilities offer as much choice in how your electricity is created as Henry Ford offered to those buying his Model T. You can have any color you want, as long as it is bIack. But as power companies face dereguIation and the prospect of competing for customers, many are beginning to sell a second, distinctly greener stream of energy. The juice flowing from solar cells, windmills and biomass furnaces is still a mere trickle running into an ocean of fossil and nuclear-fueled power. But pilot projects are revealing just how many people will pay more for electricity that pollutes less. The tiny, ciry-owned utility that serves Traverse City, Mich., gambled that many of its customers would pay a 23 percent premium (typically about $7.50 a month) to light their lamps with wind rather than coal. With a grant from the state and a subsidy from the U.S. Department of Energy, the electric company erected a giant, 600-kilowatt windmill with blades 44 meters (144 feet) in diameter-the largest such turbine in North America.

Wind turbine in transverse city provides premium-priced energy for 145 homes.

Some 145 residents and 10 businesses signed up; another 75 filled a waiting list. "That amounts to 3 percent of our 8,000 customers," says Steve, Smiley, who managed the project. Love of Mother Earth was not the only incentive for these people, he notes. "We also promised 'green' customers that we would not increase their rates in the future, since the fuel is free." Several years ago the Sacramento Municipal Utility District began installing small photovoltaic panels on the roofs of those willing to pay an extra $4 a month. Thousands applied, but the panels cost about $20,000 apiece, so the company has so fir set up only 420, enough to generate 1.7 megawatts. In May the utility signed contracts to add 10 megawatts' worth of solar cells over the next five years. The company also kicked off a new green pricing program similar to Traverse City's: for an extra cent per kilowatt-hour, subscribers will get all their electricity from new renewable sourc es. (Not literally: green cus tomers still draw power from every oil and gas-fired dynamo on the grid. But their checks pay for cleaner generators.) Some 23 other companies have followed suit. Public Service Company of Colorado has begun enlisting buyers for a 10-megawatt wind farm. Wisconsin Electric signed up more than 7,000 volunteers for hydro-electric and biomass power. The trend is encouraging, says Blair G. Swezey of the National Renewable Energy Lab, but should not be mistaken for a resurgence in renewables. In fact, utili ties are adding renewable capacity at just one fifth the rate they did a decade ago. Nonpolluting energy is closing in on the cost of coal and oil, but it is not there yet. How close is close enough? In surveys, 40 to 60 percent say they would pay more for cleaner power. "But the story changes wherl people get their checkbooks out," observes Terry Peterson of the Electric Power Research Institute in Palo Alto, Calif. Few green-power programs have enrolled more than 5 percent of ratepayers. To be sure, most were poorly advertised and asked for premiums of 20 perceni'or more. But an exception may prove to be the rule. When Massachusetts let homeowners in four cities choose among nine power vendors last summer, 16 percent chose Working Assets Green Power, which buys no electricity from nuclear or coal plants. Although Working Assets's rates were the highest of the nine competitors, they were still cheaper than the monopoly that customers were leaving. "For green pricing to make a real difference, you need to charge less than what people pay today," says Laura Scher, who managed the project. That will be difficult, Swezey argues, as long as utilities can bill customers separately for failed investments, such as prematurely closed nuclear reactors. If those costs were instead factored into the price of electricity, then wind and dam power would look like more of a bargain. Because they are not, Swezey wagers it will take several years of healthy competition before the renewable power industry starts seeing green. -W Wayt Gibbs in San Francisco


SOLAR PANEL, featuring low cost and high efficiency, is displayed by its inventor, Subhendu Guha of United Solar Systems in Troy, MiciL Guha's design uses special deposition techniques to maximize the capturing of light.

Hot Property Solar cells make a leap in cost-effectiveness Scientific American 94/5

Photovoltaic solar cells, which convert free sunshine directly into valuable electricity, are so obviously a smart idea that one wonders why the people who sell them are not rich yet. The reason is that power generated by burning coal or oil is still usually cheaper. The dismal science trumps physical science: if power lines are nearby, solar cells are too expensive and too low powered to pay for themselves over their 20 years of life. An increase in the power per unit cost could tip the economic balance, making solar energy a good investment in many more places. That is exactly what United Solar Systems in Troy, Mich, says it has now achieved. United Solar, a joint venture of Canon and Energy Conversion Devices, has developed a panel that uses low-cost, thin-fihn amorphous silicon to capture sunlight with an efficiency of 10.2 percent. That is high enough-and the panels are potentially cheap enough-to be competitive as an adjunct power source in homes, where the panels might be used as rooftng shingle. Two years ago 6 percent was the best efficiency that could be obtained with this form of silicon. Fasting photovoltaic cells that can beat the canonical 10 percent figure are made either from single crystals of silicon or from the polycrystalline form of the material. But single crystals have to be made to high precision at high temperatures and conunand cortespondingly Wgh prices. Even polycrystamne silicon is much more expensive than the amorphous form The new United Solar design, the work of Subhendu Guha, is a triple sandwich that consists of a layer of silicon combined with layers of two different silicon-germanium alloys. The layers, deposited at 300 degrees Celsius from a mixture of the gases germane, disflane and hydrogen, vary in composition across their thicknesses. That tecimological trick goes a long way toward explammg how the panels maximize light absorption, each capturing photons of a different energy. Silver electrodes carry the charge away. The sandwich is deposited on a ribbon of 12-inch-wide stainless steel, which suggests another potential advantage over existing panels: it can be bent. Energy Conversion Devices, which owns half of United Solar, has long experience with solar power: the company is the creation of Stanford R. Ovshinsky, one of the pioneers of photovoltaics. The new solar panel was developed in a three-year, $6.26-million project carried out on a cost-shared basis with the Department of Energy. Guha says the successful outcome is an argument in favor of strong government support of technology development: "This is an example of how by spending very little government can help build new industries and create high-quality jobs," he declares. United Solar is now building a plant in Newport News, Va., where starting in 1995 it plans to produce about a million square feet of solar panel per year. That is enough to produce 10 megawatts of power, or one sixth of current world demand for photovoltaics. "The Japanese are investing enormous amounts in this sort of technology," Guha warns. "It's a nice result," says Frank J. Kampas, chief of research at Advanced Photovoltaic Systems in Princeton, N.J., which is also gearing up to mass-produce amorphous silicon cans. "But I don't think they're going to put us out of besmess." Kampas's company builds its solar cells on glass, so they lack the flexibility that Guha can claim. On the other hand, Advanced Photovoltaic's panels are substantially bigger than those that United Solar will make. Neither company can yet match the cost of the cheapest electricity from fossil fuels. But even before the new development, photovoltaics was starting to make inroads. Norway has 50,000 photovoltaic-powered country homes, for example, and Paciftc Gas and Electric last year installed a 500-kilowatt plant at a substation in Cahfomia's San joaquin VaRey. Also in 1993 a coalition of U.S. utilities announced plans to introduce 50 megawatts of photovoltaic power over the next six years. The DOE predicts that the United Solar panels could bring the cost of photovoltaic power down to 12 to 16 cents per kilowatt-hour, less than half its current cost. Power companies usually now charge between six and 20 cents per kilowatt-hour for fossil fuel-generated electricity. If mass-produced panels perform as well as the United Solar prototypes, solar power might be ready to take its place as a standard auxiliary source-assuming the dismal science can be believed. -Tim Beardsley

Incredible shrinking solar panels NS 13 Jun 98 16

A DUTCH team has worked out how to make films of metal ions or semiconducting particles just one molecule thick. Such films hold out the prospect of one day making ultra-thin charged surfaces for photovoltaic solar cells or light sensors. In the 1930s, Irving Langmuir and Katharine Blodgeft of the General Electric Laboratories in Schenectady, New York, discovered that amphiphiles-molecules that are water-soluble at one end but not at the othercan be made to fan out over the surface of water in a layer one molecule thick. The molecules they used were electrically charged at the water-soluble end. Positively charged metal ions in the water bound to the film and made it electrically neutral. Arend Jan Schouten and colleagues at the University of Groningen in the Netherlands have now made a similar film with molecules whose water-soluble ends are ligands - groups of atoms that bind to metals but which are not charged. As a result, metal ions form a charged layer when bound to the film. The team has also made thin films of semiconducting particles. The film can be lifted onto a glass plate, and sandwiched against another film, made out of a different ligand. "The ion or particle then experiences a different electromagnetic environment on one side compared to the other," says Schouten. A semiconductor film could act as a photovoltaic cell. Thin films might also make good sensors, says Schouten. A single molecule of a gas, for example, could deform the optical or electrical properties of the film enough to be readily detectable. Debora Mackenzie, Brussels


Vortec wind turbine design can boost wind energy at the turbine by 175%

Vortec wind generator could cut the cost of wind power generation by half using light pre-stressed concrete cowlings to boost wind velocities through the turbine and could increasing power production for a given rotor size by a factor of four or five, by generating in a broader spectrum of wind conditions.

Shell Intemational projects a renewable energy future Scientific American 1994

Redaction is always dangerous, and predicting the fortunes of energy sources is the riskiest form of this professional sport. Still, after many years in the field Shen has a better track record than most. The giant corporation's planning group is credited, for example, with alerting the company's management to the possibility of an oil crisis before the oil price hike of 1973. So when Shell talks (particularly when it talks to itself), everyone tries to listen. At the moment, knowledgeable ears are trained in the direction of the Shell International Petroleum Company in London, a service company for the Sheu group. And what they are hearing is definitely not orthodox stuff. Shell's business environment group, headed by Roger Rainbow, has sketched a future in which renewable sources wfll grow to dominate world energy production by the year 2050. That perspective contrasts sharply with conservative studies by the World Energy Council (WEC), an international energy industry organization, and the Intemational Energy Agency (IEA), an intergovernmental body. The WEC, for example, considers that "new" renewable sources, which include solar, wind, small hydroelectric, modem biomass and ocean sources, may account for only 5 percent of the world's energy output in 2020. hi this view, fossil fuels wffl provide most of global energy needs through the middle of the next century, while nuclear fission plays an important supporting role. The WEC's projections, the result of a three-year, $ 5-million study, were pubhshed last year. According to one of its niidrange projections, annual global energy production win increase by 80 percent by 2020, to the equivalent of 16 billion metric tons of oil. That output will be needed to meet the needs of a human population that wfll be on its way from 5.5 billion (the 1990 figure) to 8.1 billion in 2020. (The numbers come from estimates by the United Nations and the World Bank.) The WEC and IFA studies presume that the new technologies wffl simply not have matured enough to capture a large fraction of the markets for coal, oil and natural gas. But Rainbow and his colleagues, notably Georges DuPont-Roc, head of the planning group's energy division, disagree. Although the Shell exercise is not yet complete, Rainbow and DuPont-Roc have given officials at the World Bank and the U.S. Department of Energy a peek at the work in progress. And Peter Kessler of the Shell group has described some of the project's key aspects to the World Petroleum Council. Kessler describes two possible geopolitical scenarios for the next 25 years. In one, the global trend toward economic liberalization and democratic reform in the 1980s continues to roll forward. That leads to a large increase in energy demand in developing countries, especially China and India, the world's most populous nations. At the same time, however, energy efficiency improves because of increased competition. Energy taxes intemahze environmental costs, which help to stimulate the development of cleaner technologies. Renewables gain importance in the second scenario, too, but less so, and in a distinctly grim setting. Regional economic and political tensions dominate the globe. Demand for ofl increases, albeit slowly, but there is far less improvement in energy efficiency than in the first scheme. Protectionist policy and law weaken market forces. Oil price shocks exacerbate deteriorating international relations, and environmental [email protected] spur government control of energy industries to ever stricter levels. New markets for renewables are "largely in poor countries" or are developed locally and cheaply. Kessler points out that the protectionist option is bad news not orily for ofl companies but also for the environment. Under any plausible view, developing countries account for most of the growth in demand over the next 30 years. If they do not gain access to new, energy-efficient technologies, they wifl follow the energy-inefficient path taken by the developed countries. Under the more [email protected] view, Kassler speculates, renewable energy technologies may well "start to be compedtive with fossil fuels around 2020 or 2030." He points out that fossil fuel technologies wffl probably be unable to lower costs as quickly as wffl the younger upstarts. Then "potential uses of the new technologies would grow." Developing countries might leapfrog over the industrialized nations toward an energy-efficient future. Kessler foresees changes on the demand side, too. Virtual reality might, he coWectures, lead to a reduction in the demand for travel, thus breaking the long-standing exponential growth in personal mobility. In any event, fossil tiel use would start to decline around the middle of next century. En-Assions of carbon dio)dde, which most atmospheric scientists expect to lead to significant global warming, would start to fag. In the niidrange futures that the WEC considers, carbon dio)dde concentrations wffl continue to rise from the current level of about 3 5 8 parts per mfflion throughout next century, reaching about 600 parts per mflhon in 2 1 00, while stffl rising. Rainbow says he is convinced that, for the long term, business-as-usual scenarios are "fundamentally and deeply flawed." He believes it is "obvious" that "there won't be that much coal, ofl and gas being used in 1 00 years." Shell has considered "green" energy ftitures in the past, but they assumed stringent environinental regulation. The new work is remarkable because it envisions a sustainable future without draconian controls, says Christopher Flavin, an energy analyst at the Worldwatch Institute in Washington, D.C. Not everyone is convinced that Shell has got the future right. Lee Schipper, an energy researcher at Lawrence Berkeley Laboratory, notes that the company deliberately considers wide-ranging possibflities. Schipper, who was himself formerly in Shell's planning group, indicates that the new analysis is "not yet good enough to go on the record." Rainbow says he expects to air more details about his group's thinking later this year. Even in its embryonic state the DuPont-Roc/Rainbow vision is applauded by environmentalists such as Flavin. He suggests that Shell's conclusions "discredit" the conservative World Energy Council predictions. Flavin believes that hydrogen generated by electrolyzing water using power from photovoltaic plants will be the fuel of the second half of next century. Nobody will predict the unfolding reality closely. But when a major ofl company effectively projects the end of the fossil fuel age, it is a sure harbinger that we are moving into the future on fast-forward. -Tim Beardsley