Powering the Future: A Scientist's Guide to Energy Independence

by Daniel B. Botkin

  And finally, there are microturbines, which generate less than 1 kilowatt but do so where it is otherwise difficult or impossible to generate electricity, and these are used to charge batteries on boats and to pump water on farms and for individual houses.30

  Downsides: wind power and the environment

  No energy source is without any drawbacks whatsoever. Wind power has only a couple: Some people don’t like the way the machines look—especially the large wind turbines, and most especially when the turbines are smack in the middle of a scenic vista—and sometimes birds fly into them and are killed. These two negatives can cause a lot of controversy.

  In August 2009, North Carolina’s state senate approved a bill that bans windmills larger than 100 feet from windy ridges in the state’s scenic western mountains. (At the time of this writing, the bill has still to go to the state House of Representatives.) According to the New York Times, “Advocates of wind energy say that if the ban becomes law, it could put as much as two thirds of North Carolina’s onshore wind resource offlimits.”31

  Not in my backyard

  The Cape Wind project, proposed by Cape Wind Associates, involves placing 130 horizontal-axis wind turbines, each higher than the Statue of Liberty, on floating offshore platforms distributed over 24 square miles (therefore not very close together) in Nantucket Sound. The turbines are expected to generate enough electricity for 420,000 homes, but although originally proposed in 2001, work on the $1-billion project has yet to begin. The federal government has received more than 40,000 comments about it, the greatest number ever about an alternative-energy project,32 and in response has held 50 public hearings. Fishermen have expressed concern about possible effects on fish habitats, including spawning grounds. Shippers have expressed concern about possible dangers for commercial shipping. And some residents of Cape Cod, Martha’s Vineyard, and Nantucket have opposed the project on aesthetic grounds—that the wind turbines will spoil the scenery.33 The late Senator Edward M. Kennedy, Democrat of Massachusetts, was one of the leaders in the fight against it, as is his nephew, Robert Kennedy Jr.34

  It is worth noting that in the meantime, a Dutch company, Blue H, USA LLC, announced plans in March 2008 to put 120 turbines on floats 23 miles south of Martha’s Vineyard and 45 miles west of New Bedford, farther away from the view of residents.35

  Further complicating matters, the National Park Service says that Nantucket Sound is eligible for listing on the National Register of Historic Places. And two tribes—the Mashpee Wampanoag of Cape Cod and the Aquinnah Wampanoag of Martha’s Vineyard—make two claims against the development: that it might be built over ancestral burial grounds and might interfere with a ritual that requires an unobstructed view of the sunrise.36

  The aesthetic concerns about wind turbines are legitimate and pose a dilemma for environmentalists, who need to choose between the national advantage of wind power and the local effects of wind turbines on landscape beauty. Proponents of other sources of energy, such as nuclear power advocate Senator Lamar Alexander, use this aesthetic argument as a reason to oppose wind energy and support nuclear energy.37

  Birds and wind turbines

  Wind turbines can usually be placed where they won’t interfere with spectacular scenery, but no matter where you put them, you can’t stop birds from flying into them. You can, however, put the wind turbines in places that birds do not use very much, or you can make a mistake and put the turbines right in the middle of a bird species’ nesting grounds or flyway.

  The 5,000 wind turbines in Altamont Pass, California, famous among wind-power enthusiasts as one of the places that started it all in recent times, killed about 1,000 birds in one year. Half of these were birds of prey, including 24 golden eagles, a species protected under the Endangered Species Act.38 This works out to about 1 bird killed a year for every 10 of the large windmills running. The California Center for Biological Diversity filed a lawsuit in 2004 against the operators of the Altamont Pass wind turbines, who in response agreed to remove 100 turbines that appeared to be in problem locations and to shut down half the turbines in winter months, when birds are most likely to fly into them. In addition, five Audubon chapters, including Golden Gate Audubon, filed another lawsuit against the county, claiming that there had been inadequate environmental review.

  Despite the problems at Altamont Pass, the National Audubon Society has endorsed wind power, arguing that on balance its environmental benefits outweigh its disadvantages, and that it has much less effect on bird mortality in other locations, partly because of the terrain and topography of Altamont Pass and because small mammals that are the primary prey of large raptors are especially abundant there. According to the National Audubon Society, “Farms and ranches of the West and Midwest are now favored homes for wind turbines, and so far they seem to be relatively safe for both raptors and songbirds. ‘The bird mortality we’re seeing is lower than what’s been seen at Altamont,’” says Tim Cullinan, director of science and bird conservation for Audubon Washington and a wildlife biologist.”39

  He went on to say, “We can’t lose sight of the larger benefits of wind....The direct environmental impacts of wind get a lot of attention, because there are dead bodies on the ground. But nobody ever finds the bodies of the birds killed by global warming, or by oil drilling on the North Slope of Alaska. They’re out there, but we don’t see them.”40

  The most notorious problem with wind turbines killing birds is at the Norwegian wind farm at Smola, a set of islands six miles off the northwest coast of Norway. In 1989 Birdlife International listed these islands as an important area for conservation of birds because they had one of the world’s highest densities of white-tailed eagles, close relatives of the North American bald eagle. Ignoring this listing and other warnings from conservation organizations, Norway allowed the construction there of Europe’s largest land-based wind-generating facility. It produces 450 million kilowatt-hours of electricity a year, but in doing so has killed 20 of the 21 local white-tailed eagles, according to the British Royal Society for the Protection of Birds (RSPB).

  Nevertheless, like the U.S. Audubon Society, the British RSPB supports wind power. Speaking for that society, Dr. Mark Avery said, “The RSPB supports increased renewable-energy generation as part of a balanced approach towards tackling climate change, which we see as the greatest threat to the world’s wildlife. However, we will object to any wind farms that seriously threaten important populations of birds and their habitats.”

  Both the U.S. Audubon Society and the British Royal Society for the Protection of Birds believe that the solution lies in adequate site assessment. They have created guidelines for wind-power installation that include several years of monitoring bird abundance, along with statewide planning so that wind turbines can be placed in locations favorable for both energy production and the birds. Their approach to wind energy is a model that we should keep in mind as we search for new ways to meet our energy needs. The best solution will be one that makes use of a variety of sources, each used to its best advantages.

  The bottom line

  • Wind-energy technology has matured rapidly in recent decades and is no longer simply experimental but a cost-effective energy source providing electricity today for distribution on the grid in the United States and other nations.

  • Wind energy is playing an important role in rural areas and in poor nations, where other sources of energy are limited and expensive.

  • Wind is cost-competitive with coal and is the least expensive of all alternative energy sources. For the cost of the Iraq War, the United States could have installed enough wind turbines to generate all its electrical energy needs.

  • Environmental concerns about wind energy focus mainly on landscape beauty and bird mortality. The Audubon Society and other environmental organizations believe that these problems are greatly outweighed by its environmental benefits.

  • Without question, wind will be a major part of the solution to our energy problem.


  7. Solar power

  Figure 7.1 Solar race car designed and built by students at the University of Minnesota passes by a wind farm near Lake Benton, Minnesota. (DOE photo)

  Key facts

  • Solar is the fastest-growing energy source.

  • It presently provides a tiny fraction of the world’s energy, considerably less than 1%, but if just 1% of Earth’s land area had photoelectric devices, all the world’s current energy needs would be met.

  • And in about 20 years the solar energy generated on 1% of Earth’s surface would equal the amount of energy in all known fossil-fuel reserves.

  • The same is true for the United States—1% of the land area would provide all of the nation’s energy needs, not just electricity.

  • But at present, solar energy is the most expensive source of on-the-grid electricity, costing about twice the average price of electricity.

  • However, solar energy can also be produced locally and in small amounts, and small solar-electric facilities are rapidly becoming more important in developing nations.

  • In Kenya, some 10,000 women have been trained to use $10 solar cookers and show others how to use them. Hundreds of thousands of these solar cookers are also in use in India.

  • In the 1990s, in Kenya alone, 120,000 photovoltaic units were sold to provide electricity for lighting, radio, television, and so on.

  Crossing Australia at almost 60 miles an hour

  Every other October since 1987, solar-powered cars have raced from Darwin to Adelaide, Australia, an 1,800-mile route that puts the latest alternative-energy technology to the test. The cars can run only on sunlight that their solar cells capture and convert to electricity. Electric motors that are at least 90% efficient are necessary. More than 50 teams—usually of college students, often backed by major aerospace and high-tech corporations—compete in the race, which takes a week.

  In 2007, among the entrants was an all-women’s team from Annesley College in Adelaide; the team designed, built, and raced their car. Only 18 cars finished. The winning 2007 team, from the Netherlands, completed the race in 33 hours at an average speed of 57 mph. A car from the United States, designed, built, and raced by students from the University of Michigan, made it in just under 45 hours at an average speed of 42 mph. The only other U.S. entrants did not even finish the race: The Equinox from Stanford University reached 1,158 miles, more than halfway, and Houston’s Sundancer made it only 89 miles down the road from Darwin.1 (Was this a sign that the United States might be losing its place as No. 1 in high-technology inventions, research, and development?)

  As I write this in the summer of 2008, a website announces the next challenge in this race from the Swiss team, which promises more and more advances. Solar-powered car races aren’t all that frequent, but devices powered by the sun are becoming familiar, even ordinary. In the United States, if you look carefully you are likely to find solar-electric devices near home. A drive along a major highway reveals emergency telephones and emergency highway signs powered by solar-electric panels. Some wristwatches are solar-powered, and you can buy a little solar electrical generator to recharge your iPod and your Blackberry.

  At a much larger industrial scale, solar energy parks, large facilities that generate electricity that goes onto an electric grid, are rapidly increasing in number, and at this point it’s hard to know at any time which is actually the world’s biggest working facility (Figures 7.2 A, B). At this writing, the prize goes to two locations in Spain, both with a 20-megawatt capacity—one in Jumilla, Murcia, and the other in Beneixama. Both are said to provide enough electricity for 20,000 houses, and both are where you would expect to find solar energy installations—in a warm sunny climate. (These sites average 300 sunny days a year.)

  Figure 7.2 (A) Largest solar photovoltaic installation in the Western Hemisphere, near Orlando, Florida. (Photo courtesy of SunPower Corporation)

  Figure 7.2 (B) Obama at that Western Hemisphere’s largest solar park. (Photo courtesy of SunPower Corporation)

  The kinds of solar energy

  Two kinds of solar energy are in use: active and passive. Passive solar energy is at work in buildings designed to absorb and reflect sunlight in ways that reduce the need to burn fuels for heating or cooling. No motors are used to move air or water or any material storing the energy. The way an automobile heats up when parked in the sun is an example of passive solar energy. Passive solar energy is often discussed as part of energy conservation, and we discuss it in Chapter 10, “Transporting Energy: The Grid, Hydrogen, Batteries, and More.” Right now we’ll talk about active solar energy.

  Active solar energy uses electrical, electronic, or mechanical technologies to store, collect, and distribute solar energy for heating and cooling; to generate electricity; or (much more rarely) to do mechanical work directly. This chapter focuses on active solar energy technologies as sources of energy, primarily to generate electricity, but also, once the electricity is available, to use that energy to make chemical fuels.

  Active solar energy, in turn, divides into two major technologies: those that convert sunlight directly into electricity, and those that use sunlight to heat (and boil) water, which is then used to run a conventional electrical generator or to provide hot water and space heating in a system that involves mechanical pumps and various control devices, including computers. (The pumps and controls distinguish active solar energy from passive solar heating of buildings.)

  Solar thermal generators: sunlight to steam to electricity and big bright lights

  The first large-scale test of using sunlight to heat water and using that to run an electric generator was Solar One, funded by the U.S. Department of Energy, built in 1981 by Southern California Edison and operated by that company along with the Los Angeles Department of Water & Power and the California Energy Commission. Here’s the way it worked: Sunlight was focused and concentrated onto the top of a tower by 1,818 large mirrors (each about 20 feet in diameter) that were mechanically linked to each other and tracked the sun. It is a system that would have delighted Archimedes, who is said to have used mirrors to focus sunlight on enemy ships and burn them, probably the first military use of solar energy.

  Solar One became famous to those of us in Southern California interested in the environment. I was teaching at the time at the University of California, Santa Barbara, and I drove on I-40 to Barstow to see this remarkable new device. It was impressive, especially when viewed in late afternoon among the long shadows of the surrounding desert. The mirrors reflected so much sunlight onto the tower that its top seemed aglow, as if it were a miniature sun emitting its own, not reflected, light. In fact, it was so bright that you couldn’t look at it directly for long, as the accompanying photograph shows somewhat (Figure 7.3).

  Figure 7.3 Solar One, the first major solar thermal tower, was built in the Mojave Desert near Barstow, California, several hundred miles east of Los Angeles. Originally it was an experiment funded by the Department of Energy and built and operated by Southern California Edison. (Photo by Daniel B. Botkin)

  Solar One, still at the same location in the California desert, was improved in the mid-1990s and called Solar Two. Its mirrors and everything else necessary to run the system took up 126 acres—the mirrors alone had an area of 20 1/2 acres of reflecting surface!—and it operated with a capacity of 10 megawatts until it was shut down in 1999. Even today, it stands out in my memory as the most impressive view of the use of solar energy, almost magical in its brightness.

  More recently, solar devices that heat a liquid and produce electricity from steam have used many mirrors without a tower, each mirror concentrating sunlight onto a pipe containing the liquid (Figure 7.4). This is a simpler system and has been considered cheaper and more reliable.

  Figure 7.4 Researchers analyze the efficiency of using parabolic troughs for solar thermal systems. (DOE photo)

  Solar electric generators: using very large, smooth surfaces to convert sunlight to electricity

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nbsp; The other major active solar energy technology uses solid-state devices that generate an electric current when exposed to light. If they weren’t so common today, they would seem quite magical, like the solar energy flashlight I bought recently—you just lay it on the windowsill, and whenever you need light to use in the dark, you have it. These devices are called photovoltaic cells, and the most common of them is a silicon wafer, which is made of crystals of silicon. These make up 60% of the devices sold.2 This is the same kind of material used to make computer integrated circuits. In fact, one photovoltaic company, Astropower, now out of business, used rejected materials from the manufacturing of computer chips. Silicon, by the way, combined with oxygen makes up most of the sand on beaches and is a very common material.