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

by Daniel B. Botkin

  Gas hydrates are frozen forms of organic gases, mainly methane, and are often referred to simply as methane hydrates. In a kind of water-ice matrix, they are buried in the ocean below 3,000 feet, where the temperature and pressure are sufficient to freeze the gas, and also in organic material in permafrost, where their emissions in small amounts are called marsh gas. Ocean deposits of methane hydrates were discovered only about 30 years ago, and only rough estimates of their quantity are available, but these suggest that methane hydrates might double, or even more than double, the total amount of energy available in all other known fossil fuel deposits—coal, oil, and natural gas (Figure 2.9). The problem is that methane hydrates are difficult to release from their ice matrix and make usable. A start has been made, but mining this gas is still in the experimental stage, with several test wells in Canada in development by the government of Japan.8

  Figure 2.9 Methane hydrates may be the largest source of organic carbon in the Earth. (U.S. Geological Survey, Gas [Methane] Hydrates—A New Frontier, Dr. William Dillon, Keith Kvenvolden, USGS)

  Coal-bed methane

  We discuss coal in detail in Chapter 3. In brief, coal is formed when woody plants—trees and shrubs—die, are buried in wet ground, which limits the kinds of decay, and are later buried deep by new deposits above them. Heat and pressure from the newer deposits above convert the dead wood first to peat, then to lignite, and then to coal. Each step increases the amount of fuel and decreases impurities, including water. During this process, a lot of methane is produced, largely by the activity of certain kinds of bacteria that live only in the oxygenless environments of material soaked in water. This methane is released naturally in relatively small amounts by the heat and pressure, bubbling to the surface as swamp gas. But this natural gas can also be mined, and estimates are that there may be a lot of it available. According to one estimate, more than 20 trillion cubic meters of coal-bed methane may exist in the United States, of which about 3 trillion cubic meters could be mined economically today—about a 5-year supply at current rates of use of natural gas.9 One drawback is that mining this gas will no doubt cause environmental damage similar to some forms of coal mining (discussed in the next chapter).

  Natural gas from shale

  Shale is one of the most common kinds of rock in the United States, readily found in 23 states (Figure 2.10). It forms the reddish earth common on the coastal plains of New Jersey and other states that front the Appalachian Mountains, and also out west in such states as Oklahoma and Texas. Like methane hydrate, gas from shale has captured a lot of attention and interest. One of the first areas of focus is Barnett Shale near Fort Worth, Texas. In mid-2008, 7% of U.S. natural gas production was said to be coming from this one formation.

  Figure 2.10 Potential locations of natural gas to be obtained from shale. (Source: Energy Information Administration, May 28, 2009)

  In April 2008, the Wall Street Journal reported that estimates of the amount of gas that might be obtained from shale varied widely: “In 2002, the U.S. Geological Survey estimated there may be 1.9 trillion cubic feet,” the article said, but “earlier this year, Terry Engelder, a Pennsylvania State University geosciences professor, made what he called a conservative estimate of 168 trillion cubic feet. His estimate has yet to be confirmed. By comparison, the U.S. consumed 23.05 trillion cubic feet last year, according to the Energy Information Administration.”10

  Four months later, in August, 2008, estimates had increased to “842 trillion cubic feet of retrievable gas in shales around the country, enough to supply about 40 years’ worth of natural gas, at today’s consumption rate,” according to an article in the New York Times.11

  Although it has been known that shale contains natural gas, until recently the technology was not available to retrieve it. The new technology to get at this gas involves drilling very long wells that lie horizontally within the rock, rather than descending vertically through it. Hot water is then pumped into the horizontal wells, and this fractures the rock, releasing the gas.12 The reality is that this is a new form of strip mining, with all the environmental problems that result from that method, which I will discuss in more detail in the chapter on coal.

  In all the excitement about natural gas as the solution to our energy problem, such consequences seem to be overlooked. However, Kate Sinding, a lawyer for the Natural Resources Defense Council, was quoted in the New York Times warning that intensive use of water in recovering gas from shale could pose an environmental threat, especially to local and regional water supplies. And an article in the Wall Street Journal showed a sinkhole the size of a football stadium (see this chapter’s opening photograph) that was created in Texas by drilling for oil and injecting water into the ground to obtain natural gas from shale. That article stated that in 2006 alone more than 280 billion gallons of liquids, mostly water, had been injected into the ground as part of mining.13 That’s as much water as 7.8 million Americans use on average in a year.

  According to another article in the Wall Street Journal, “federal regulators, environmentalists, and community groups worry that lax oversight is allowing some of the water—which can be ten times as salty as seawater and often contains oil, heavy metals, and even radioactive material—to escape from underground reservoirs. That could lead to the contamination of underground drinking-water supplies, the pollution of soil and surface water, and more sinkholes as underground structures are eroded.”14

  In short: If we are going to go the route of gas from shale, we had better expect a lot of pollution, similar to the effects of strip-mining coal.

  As you read throughout this book, I believe that the solution to our energy problem will involve a variety of sources. Natural gas is the best and cleanest of the fossil fuels and, therefore, the one fossil fuel that we should emphasize. But to what extent and for what uses? Before making any decisions about that, we have to explore the other sources of energy, and that is what we do in the next chapters.

  The bottom line

  • Of the fossil fuels, natural gas has become the darling, with famous businessmen and politicians promoting it as the clean, cheap, and abundant fuel of the future.

  • Natural gas is the cleanest to burn of the fossil fuels and is especially valuable for such uses as urban transportation, where it is important to minimize local chemical and particulate pollution of the air, and for running small turbines for peak power production.

  • U.S. natural gas reserves cannot provide energy-independence for very long, because natural gas from traditional wells is limited within the United States. The largest potential sources of natural gas are in the deep sea, in coal beds, and in shale, and obtaining natural gas from these new sources is challenging and can create large-scale environmental problems.

  • Natural gas will continue to be important for cooking and space heating, but despite what you may hear, obtaining enough of it for transportation and other uses for America’s growing population and for the world in general will not be easy or cheap.

  • Even if the kinds and rates of use remain at 2006 levels, readily available natural gas from wells that pollute little would last less than a decade. And if it becomes a major fuel for cars and light trucks, U.S. natural gas from minimally polluting wells will run out even sooner.

  3. Coal

  Key facts

  • Coal provides nearly 60% of electricity and 25% of total energy in the United States today.

  • There are 476 coal-fired power plants in the United States. Advocates propose about 150 more, some of which are in construction; others have been approved by the government.

  • Coal use is increasing rapidly around the world and reaches a new record high each year in the United States.

  • China is rapidly building more coal-fired power plants and may soon catch up with the United States in both the amount of electric power produced from coal and the amount of CO2 released in the process.

  • At current and projected rates of use, coal reserves will last anot
her 150 to 300 years.

  • Coal, along with nuclear power, is the dirtiest form of energy, and coal mining and burning have a long history of causing damage to the environment and to human health. Coal mining has destroyed towns, landscapes, mountaintops, rivers, and streams. Coal burning releases toxic elements such as lead, mercury, and arsenic and is a leading cause of air pollution and acid rain.

  This coal comes with laundering instructions

  Just before Christmas 2007, a consortium of some of the world’s major electric utilities and coal mining companies—American Electric Power, Peabody Energy, Rio Tinto Energy America, and Southern Company, along with Australian, British, and Chinese companies—announced that a new kind of coal-fired electric power plant would be built in Mattoon, Illinois, which would provide the cleanest power in the world. The planned new power plant was part of the U.S. federal FutureGen program, announced in 2003 by President George W. Bush. The claim was that its power generation would be clean because instead of burning coal directly, the energy in the coal would be converted to hydrogen gas, and the carbon dioxide released from the burning coal would be buried deep in the ground rather than released into the atmosphere. The Illinois plant was planned to generate 275 million watts and cost $1.4 billion; $1 billion of which would come from the federal government. It was supposed to begin operating in 2015.2

  Transferring the energy in solid coal to a gas is not new—it was invented in the 18th century. In the early 1800s, before the invention of the electric light, coal gas fueled streetlamps in London (the first to have this kind of lighting) and Philadelphia (America’s first coal gas stree-tlights), Boston, Washington, D.C., and New York (Figure 3.1). At that time, street lighting from coal gas was new and considered a great advance. Coal gas began to light homes by 1830.3

  Figure 3.1 A coal-gas streetlamp in 19th-century Washington, DC.1 The crossbar just below the glass lamp is a place for the lamp lighter to rest his ladder. (Source: Library of Congress, the Brady Collection, LC-DIG-cwpb-03640)

  Although coal gas technology has been around for almost two centuries, the FutureGen power plant in Illinois was to be new in two ways: It would be the first operational plant to bury carbon dioxide produced from burning coal, and it would combine this with the latest method to make coal gas, called an integrated gasification combined cycle (IGCC). The IGCC method of coal gas production is used in only four power plants around the world: Puertollano, Spain; Buggenum, the Netherlands; Terre Haute, Indiana; and Polk County, Florida.4

  “There is no project in the world that can move near-zero-emission power and CCS (carbon capture and storage) further or faster than FutureGen at Mattoon,” Senator Dale Righter, Republican of Illinois, said. “Today I could not be more proud.... I look forward to the next step where we make this promise of economic evolution a reality.” However, FutureGen’s electricity is estimated to cost three times as much as energy from a conventional coal-fired power plant. As we will see in later chapters, this raises the cost beyond electricity from wind power and approaches that from solar power.5

  And will it work? And even if it does work, will it be worth $1 billion of the taxpayers’ money? And is it the best way to get cleaner, more secure, sustainable energy? This chapter can help you to make a decision about FutureGen and the future of coal in general.

  What exactly is coal?

  Coal is fossilized land plants that have been buried deep in the earth for millions of years. Although the intense heat and pressure at those depths have converted the vegetation into a hard, black material that is primarily pure carbon, you can still see the leaves and stems of plants in the fossils. Most coal was formed during the Carboniferous and Permian periods, 363–245 million years ago, and in the Cretaceous period, 146–45 million years ago, when wetlands were widespread.6 Dead vegetation that lay buried in large wetlands could not decay, because the water prevented oxygen in the air from reaching it.

  There are four kinds of coal, depending on how long the plant material has been underground, at how high a temperature, and under how much pressure. Anthracite (hard coal) is the hardest and best coal fuel because it is 86% to 98% carbon and has the fewest impurities. Bituminous (soft coal) is the most abundant but is softer than anthracite, has a lot of impurities, and is only 69% to 86% carbon. Subbituminous (medium-soft coal) is even softer and has more water and impurities. Lignite (brown coal) is the worst stuff, very soft, 70% water, and less than 30% carbon. Of the four, anthracite, the cleanest and with the least water, is the best for home heating. The others are used primarily to produce electricity, and bituminous coal is also used to make coke, which in turn is used with iron to make steel.7

  It is estimated that the Earth contains approximately 1 trillion tons of coal. The energy stored in this is somewhere between 4.76 and 7.64 million billion kilowatt-hours, a number hard to imagine. Here’s a try: Hoover Dam, as mentioned earlier, generates 4 billion kilowatt-hours a year, so the world’s total coal reserve contains the amount of energy that would be generated by 1 to 2 million Hoover Dams running at full capacity for one year, or, if you prefer, 1 Hoover Dam running for 1 to 2 million years, or about 100 Hoover Dams running for 10,000 years—about the length of time that human civilization has existed on Earth. No matter how you look at it, there is a lot of energy stored in coal, thanks to woody plants that over hundreds of millions of years did not decay but just lay quietly, buried and stored.

  Like oil and natural gas, coal is distributed unevenly around the world, but coal is found in more locations than the other fossil fuels—70 nations have recoverable coal, but 10 nations currently produce 95% of the world’s coal (Figure 3.2).

  Figure 3.2 Although there is a lot of coal around the world, these ten nations mine most of it.

  The United States has a lot of coal—it is the second-largest producer, behind only China in its mining. Coal in the United States is concentrated in the central and southern Appalachian Mountains of the East and in the western Great Plains, with some in the Midwest (Figure 3.3).

  Figure 3.3 Where coal is mined in the United States. Percentages are changes in production from 2005 to 2006. U.S. total production is approximately 1,170 million short tons. (Source: Energy Information Administration, Quarterly Coal Report, October-December 2008, DOE/EIA-0121)8

  How much coal does the world use?

  Coal was important to the beginning of the Industrial Revolution, providing abundant energy in the 19th century but also causing great human misery and environmental degradation. Because we don’t use it much anymore to heat our homes, and given that the picturesque coal-fired steam engines are long gone, you may think people are using less and less coal. But although it may not be very visible, worldwide use of coal is actually growing faster than the use of the other fossil fuels, increasing 9% between 2006 and 2007, and 92% in the last 25 years.9 The amount of coal mined in the United States is also increasing, reaching record levels in each year of the 21st century.10

  People of the world currently use 3.4 billion tons of coal a year, which provides 25% of the world’s total energy use and 40% of the electricity. Coal is the major fuel used to produce electricity. (Petroleum, you recall, leads in transportation and natural gas in home heating and manufacturing.) The United States gets about half of its electricity from coal, and some nations depend even more heavily on coal for electricity production. For example, Poland and South Africa get 93% of their electricity from coal, China 78%, Israel 71%, and India 69%.

  The United States, India, and China are expected to be the dominant users of energy in the next decades, and since these three depend heavily on coal for electricity, it’s going to be difficult to wean them off it.

  Coal is also essential to making steel, because it is the carbon in coal that turns iron into much harder steel. But only 2% of the coal used in the United States goes into steel production; 92% is used to produce electricity, and almost all the remaining 6% is used in other industrial processes. Today Americans use only a small fraction—o
ne-tenth of one percent—for home heating. This is a big change from a century or so ago, when many homes in the United States (and in Europe as well) were heated with coal.11 But the dirtiness of coal—its heavy, toxic smoke spewing from chimneys and leaving black dust over everything, as well as large quantities of ash that had to be shoveled out and disposed of—led people to speedily abandon it for home heating as soon as oil and then natural gas became readily available.

  Are we going to run out of coal?

  Eventually, yes, but since there’s more of it, coal won’t disappear as fast as oil and gas will. At current rates of use, coal should last between 150 and 300 years.12 But the key question is not the total amount in the ground, but the amount that can be recovered economically and energetically. As we mentioned earlier, economically recoverable means that a mining company can sell the coal it obtains for more than it cost to mine it. Energetically recoverable means that the amount of energy in coal at the point of use is greater than the energy expended to obtain it and transport it to that location, including the energy costs of all indirect activities, such as pollution control resulting from mining, other production costs, and transportation.