Power Hungry (9 page)

Now let's consider energy density. An easy way to understand energy density is to consider the amount of energy contained in a 5-gallon bucket that is filled with gasoline. Now consider that same bucket filled with dried leaves. Obviously, the energy density in the bucket filled with gasoline is far greater than the energy density in the one filled with leaves. Or consider corn ethanol. Although farm-state politicians and agribusiness promoters have been able to foist their fuel on motorists in non-farm states, ethanol contains just two-thirds of the heat energy of gasoline, meaning that motorists who use ethanol-blended gasoline must refill their tanks more often.

Our quest for power density provides another argument against a return to renewable energy sources. The kinetic energy of the wind and the solar radiation from the sun are diffused. Some companies, such as General Electric and Vestas, manufacture huge turbines to turn the diffused kinetic energy of the wind into highly concentrated energy in the form of electricity. Photovoltaic cells capture diffused light energy and concentrate it into electricity, which is then fed into wires. Concentrated thermal solar-energy systems employ huge arrays of mirrors to concentrate sunlight so that it can be used to heat a fluid that can then be used to run a generator. But with both wind and solar, and with corn ethanol and other biofuels, engineers are constantly fighting an uphill battle, one that requires using lots of land, as well as resources such as steel, concrete, and glass, in their effort to overcome the low power density of those sources.

For millennia, humans relied almost completely on renewable energy. Solar energy provided the forage needed for animals, which could then be used to provide food, transportation, and mechanical power. Traveling
on lakes, oceans, or canals was made possible by the wind, human muscle, or animal muscle. And though today's wind turbines are viewed as the latest in technological achievement, land-based systems that captured the power of the wind have been recorded through much of human history. About 1,000 years ago, a visitor to Seistan, a region of eastern Iran, wrote that the wind “drives mills and raises water from streams, whereby gardens are irrigated. There is in the world (and God alone knows it) nowhere where more frequent use is made of the winds.”
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The use of hydropower, likewise, goes way back. The ancient Greeks used waterwheels; so did the Romans, who recorded the use of waterwheels in the first century B.C.
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The use of mechanical power from water continued to the beginning of the Industrial Revolution. And while solar, wind, and water power all provided critical quantities of useful energy, they were no match for coal, oil, and natural gas. Hydrocarbons provided huge increases in power availability, allowing humans to go from diffused and geographically dispersed power sources to ones that were concentrated and free of specific geographic requirements. Hydrocarbons were cheap, could be transported, and most important, had greater energy density and power density.

That increasing availability of power has allowed us to do ever-greater amounts of work in less time. And because we need power for many different applications, we have lots and lots of engines, turbines, and motors. In fact, the engines of our economy are, in fact, just that: engines. And some of those engines are enormous.

At its most basic level, the $5-trillion-per-year global energy sector—the world's biggest single business—exists primarily to feed the engines that permeate our towns and cities. Big Oil, Big Coal, and the Big Utilities are servants of the world's engines. Whether those engines are fueled with oil, coal, natural gas, or enriched uranium doesn't really matter to consumers. What matters to them is that they continue to have a plentiful supply of fuel that can be fed into those engines so that the engines can continue to turn the heat energy in the various fuels into motion.

In the process of turning that heat energy into motion, engines now generally lose about two-thirds of the heat content in the various fuels. But once again, that matters little to consumers, who are primarily interested in power that is cheap, abundant, always available, and as clean
as possible. For someone living in midtown Manhattan or central Tokyo, the idea of using coal or firewood to cook dinner is absurd. The only fuels that meet the clean air standards of those urban settings are natural gas and electricity. Furthermore, the more cheap, abundant, clean power those consumers get, the more they use. The result: Over the past few decades, energy consumption among city dwellers has increased, a fact that can be proven by peeking inside the average apartment. Three decades ago, that apartment might have had the standard kitchen appliances—toaster, stove, refrigerator, and mixer. Today, that same kitchen will almost certainly have all of those appliances as well as a microwave oven, bread maker, coffeemaker, juicer, convection oven, dishwasher, and food processor. And a few steps away, where there once was only a small black-and-white television, there is now a giant-screen TV, a DVD player, and digital video recorder, as well as a laptop computer and ink-jet printer. In 1980, the average U.S. household had just three consumer electronic products. Today, it has about twenty-five of those devices.
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PHOTO 2
This massive diesel engine, designed by Finland-based Wärtsilä, is used on large ships (see
www.wartsila.com
). Each cylinder has a diameter of about 1 meter and displaces about 1,800 liters. The Wärtsilä engines, which can turn about 50 percent of the thermal energy in diesel fuel into useful power, are among the most efficient engines ever produced.

All those electronics have had a clear result: The amount of power that we are able to consume in our homes has dramatically increased. And that spike in power use is not just happening in Manhattan and Tokyo; it's happening all over the world, accelerated by the ongoing worldwide migration toward city living. In 2008, according to the International Energy Agency, about half of the world's population was living in cities. By 2030, that percentage is expected to rise to 60 percent.
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And that will mean a corresponding rise in demand for power, because city dwellers use more power than their rural counterparts.
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The inexorable quest for power—whether in the form of computing power, a bigger engine in a new car or a better vacuum cleaner—will continue apace. Why? Because consumers and entrepreneurs are always seeking better, more efficient technologies that allow them to do more things faster. Computer makers such as Apple or Lenovo wouldn't be in business for very long if they started selling computers that were slower and had less computing power than the ones they had built two years earlier. Or imagine what would happen if a carmaker such as BMW or Mercedes Benz announced that its newest convertible took longer to go from 0 to 60 miles per hour than the model it built the previous year. The company's market share would vanish faster than Dick Cheney's hunting partners.

Power is like sex and Internet bandwidth: The more we get, the more we want. And that's one of the biggest problems when it comes to energy transitions. We have invested trillions of dollars in the pipelines, wires, storage tanks, and electricity-generation plants that are providing us with the watts that we use to keep the economy afloat. The United States and the rest of the world cannot, and will not, simply jettison all of that investment in order to move to some other form of energy that is more politically appealing.

Yes, we will gradually begin moving toward other forms of energy. But that move will be just that: gradual. And for those who doubt just how lengthy energy transitions can be, history offers some illuminating examples.

Wood to Coal to Oil

 

 

 

 

G
IVEN OUR CURRENT OBSESSION with Big Oil and Big Coal, it's worth noting that the fuel source that has had the longest reign in the American energy business is plain old firewood. Wood's reign as the most important fuel in the United States lasted longer than any other. For 265 years after the Pilgrims founded the Plymouth Colony, and for 109 years after the signing of the Declaration of Independence, wood was the dominant source of energy in America. It wasn't until 1885—the year that Grover Cleveland was first sworn in as president—that coal finally surpassed wood as the largest source of primary energy in the United States.

For the next seventy-five years, coal was king. During the first two decades of the twentieth century, coal was supplying as much as 90 percent of all the primary energy in the United States, fueling factories, heating homes, and providing boiler fuel for essentially all of the nation's electric power plants. But coal's dominance was not to last. Thanks in large part to the booming demand for kerosene for lighting, and more particularly, for gasoline to fuel automobiles, oil began whittling away at coal's market share.

World War II was a turning point. The massive production of airplanes, ships, and motor vehicles during the war years accelerated the demand for oil. And prolific oil fields in Texas and Oklahoma were ready and able to provide nearly all the gasoline and diesel fuel that consumers and industry wanted. Between 1945 and 1950, the number of cars on
U.S. roads increased by 60 percent. Over the next ten years, the U.S. auto fleet grew by another 50 percent.
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The increasing mobility of the average American resulted in a huge increase in demand for oil. In 1949, coal accounted for about 37.4 percent of the U.S. primary energy market, with oil trailing close on its heels with a 37.1 percent share. But in 1950, oil hit the tipping point, surpassing coal as the biggest source of U.S. primary energy. And for the past sixty years, oil's primacy has not been challenged. In fact, in 2008, oil's share of the U.S. energy market was at the exact same level as it was back in 1950: 38.4 percent.
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Source
: Energy Information Administration, Annual Energy Review 2008,
Figure 5
, “Primary Energy Consumption by Source, 1635–2008,”
http://www.eia.doe.gov/emeu/aer/ep/ep_frame.html
.