2. Natural gas

Natural gas is capturing the public’s imagination, especially since many well-known people, from T. Boone Pickens to Nancy Pelosi, have praised it as the cheap, clean, and abundant fuel for the future. But new technologies for drilling for natural gas will have large environmental effects, like this sinkhole in Texas (Figure 2.1) where large amounts of water were pumped into the ground to release gas from the rocks below.

Figure 2.1 A large tank, center, falls into a sinkhole near Daisetta, Texas. The sinkhole was caused by mining beneath the surface for natural gas. (Source: © AP Photo/KHOU-TV, Bobby Bracken)¹

Key facts

• Almost a quarter of all energy used in the world and in the United States is provided by natural gas.

• At current rates of use, the world’s known reserves of natural gas will last about 60–65 years, to about 2070—longer than petroleum.

• But if the United States seeks energy independence and obtains natural gas only from within U.S. borders, our reserves will be exhausted in just 16–17 years, even at the 2006 rate of use.

• In contrast to petroleum, natural gas has played a small role in powering vehicles. In the United States, about 20% of it is used to heat homes and about one-quarter of it to generate electricity (some of which, of course, may be used to power vehicles, especially trains). Most of the rest is used for office buildings and manufacturing.

Is Utah leading the way to the future fueling of cars and trucks?

It may seem surprising, but until recently natural gas was considered an unusable waste and was burned off at oil wells and refineries since it was difficult and dangerous to transport. That problem was solved by long-distance pipelines and by transporting liquefied natural gas by ship, train, and truck. Utah was the first of the 50 states to make a major push to use natural gas for automobiles, and by the end of August 2008, when gasoline was surging above $4 a gallon, the idea was a big hit. Unusual everywhere else at the time, compressed natural gas was said to be widely available for automobiles in Utah, and it was cheap, about 87 cents for enough to run a car the same distance as a gallon of gasoline.

The idea had a lot of support—“Utah shows that the technology is here and the fuel works and the fuel is better than foreign oil,” said T. Boone Pickens, who has been promoting natural gas and pushing for a big transition from petroleum to alternative energy by using natural gas as the major intermediary. When Jon M. Huntsman Jr. was governor of Utah (he’s now the American ambassador to China), he spent $12,000 of his own money to convert the state SUVs he drove so they could run on natural gas. “We can create a model that others can look to,” he said. “Every state in America can make this a reality.”² T. Boone Pickens’s energy plan, available on his website, states that “natural gas is our country’s second largest energy resource and a vital component of our energy supply. Ninety-eight percent of the natural gas used in the United States is from North America. But 70% of our oil is purchased from foreign nations.” It goes on to say that “domestic natural gas reserves are twice that of petroleum. And new discoveries of natural gas and ongoing development of renewable biogas are continually adding to existing reserves.”³ Congress got into the act as well, with Nancy Pelosi, Speaker of the House, saying on “Meet the Press” that “you can have a transition with natural gas that is cheap, abundant, and clean.”

It sounded like a good idea. But at the same time in Utah there were hints that natural gas might not be the easy panacea that Pickens, Pelosi, and Governor Huntsman were suggesting. At rush hour, stations selling the gas were finding that the pressure was running low, and sometimes people couldn’t find enough to fill more than half a tank. The supply couldn’t meet the demand—and that was when only 6,000 of the 2.7 million vehicles registered in Utah were running on natural gas. Not only was there a shortage of filling stations selling natural gas in the state, but also a car’s tank could hold only enough compressed gas to take you about half as far as a tank of gasoline.

Still, natural gas was promoted across the country, and plans were developing rapidly to increase the number of natural-gas-powered cars through government subsidies. The New York Times reported in August 2008 that “a proposal on the ballot in California this fall would allow the state to sell $5 billion in bonds to finance rebates of $2,000 and more to buyers of natural gas vehicles. Legislation has been introduced in Congress to offer more tax credits to producers and consumers and mandate the installation of gas pumps in certain service stations, with the goal of making natural gas cars 10 percent of the nation’s vehicle fleet over the next decade.”⁴

How much energy does and could natural gas provide?

At present, natural gas provides 22% of the energy used in the United States, which makes us one of the world’s heaviest users of this form of energy. About 20% of the natural gas we use is for heating homes, and about one-quarter generates electricity (Figure 2.2). Transportation uses 28% of America’s energy, and of that 28%, hardly any—one-tenth of a percent—comes from natural gas. (Although, to make things more complicated, some of the electricity generated from natural gas powers vehicles, especially trains.)

Figure 2.2 U.S. uses of natural gas in 2008. Vehicle use was only 0.1%. (Source: Energy Information Administration, Natural Gas Annual 2008 [August 2009])

Could natural gas really power as many as 10% of all U.S. vehicles within ten years? Or could the beginning of problems with the natural gas supply for automobiles in Utah be a hint as to what the future might bring for all of us? I began to look into the numbers about natural gas, as I had done for all other forms of energy, and here’s what I found.

To learn about natural gas’s potential, I contacted Ray Boswell, manager of Methane Hydrate R&D Programs, U.S. Department of Energy, National Energy Technology Laboratory, in Morgantown, West Virginia.⁵ He provided the basic information shown in Figure 2.3, which in turn enabled me to make the calculations in Figure 2.4. The shocking result is that with U.S. natural gas independence—that is, using only natural gas obtained within U.S. borders—even at the 2006 rate of use, the readily available gas within the United States would be exhausted in one year; that plus what is called “technically recoverable” would be gone in less than a decade; and what is termed “unknown but probable” would last about a century.

Figure 2.3 America’s natural gas resources, in trillions of cubic feet. (Source: Ray Boswell, U. S. Department of Energy)

Figure 2.4 How long would U.S. natural gas last? This graph shows projected years remaining for “readily available,” “technically recoverable,” and “unknown but probable” natural gas reserves and resources at 2006 rates of use. (Source: Ray Boswell, U. S. Department of Energy)

Suppose we went all the way with the suggestion by T. Boone Pickens, Nancy Pelosi, and Governor Huntsman, and suddenly, tomorrow, all automobiles and light trucks were able to run on natural gas. As we discuss later (see the chapter on transporting ourselves and our stuff), of all transportation methods, cars and light trucks are the biggest petroleum guzzlers, using 63% of transportation energy in the U.S. This change would increase the total percentage of energy provided by natural gas to just under 40%, our nation’s “readily recoverable” plus “technically feasible” supplies would last less than 6 years, and the “unknown but probable” resources alone would get us another 8 years. Note that this continues to assume that all other use will remain at 2006 levels. (Use will most likely rise with the growth of America’s population, but could in fact decline with increased efficiency of cars and light trucks and an increasing number of electric vehicles whose energy comes from sources other than natural gas.)

In July 2009, the Department of Energy announced that the estimated U.S. gas reserves in the category “marginal gas: targets for accelerated technology” were 35% larger than previously estimated.⁶

Also in 2009, the Potential Gas Committee issued a report that categorized natural gas somewhat differently and did not include the Department of Energy’s “unknown but probable” (Figure 2.5).

Figure 2.5 Another estimate of U.S. natural gas reserves, 2008.

We can also calculate how many years U.S. natural gas reserves would last based on the Potential Gas Committee’s estimates and the use at 2006 rates with the addition of providing fuel for all cars and light trucks (Figure 2.6). The result is a total of 11 years before the U.S. runs out of natural gas.

Figure 2.6 Years remaining of U.S. natural gas, using PGC 2008 estimates and assuming that use is at 2006 rates and that all cars and light trucks use only natural gas.

The take-home story is that an energy-independent America could fuel its cars and trucks only with natural gas for less than 20 years, unless we consider the most speculative and environmentally destructive natural gas sources. I am not a petroleum geologist, or a geologist of any kind, so I cannot tell you how good the chances are that the “unknown but probable” is actually out there. My correspondence with Ray Boswell and others suggests, however, that the chances are good, and that if we are willing to take a risk, we might enjoy natural-gas energy independence for as long as a century. This would require sizable upscaling of exploration for this fuel, and the question is not simply whether we want to take this risk for 80–100 years of energy independence but whether we have to take this risk. What about the environmental effects of natural gas? It is the cleanest fossil fuel, but is it the completely clean fuel that is being suggested?

World use of natural gas

Worldwide use and availability of natural gas are much the same as in the United States. Natural gas provides 26% of the energy used worldwide, slightly more than the 24% provided by coal but only about two-thirds the amount provided by oil. And at present rates of use around the world, recoverable natural gas will last about 60–65 years, according to the U.S. Energy Information Agency (see Figures 2.7 and 2.8).

Figure 2.7 Worldwide per-capita consumption of natural gas in tons per person. The U.S. and Canada are among the greatest per-capita users of natural gas. (U.S. EIA. International Energy Annual 2006)

Figure 2.8 World reserves of natural gas as of January 1, 2009. (Source: U.S. Energy Information Agency. Redrawn by DBB 31 Jan 10.)⁷

Global use of natural gas equals about 30 trillion kilowatt-hours a year. By comparison, Hoover Dam generates 4 billion kilowatt-hours a year, so the total world use of natural gas equals the energy produced by 7,500 Hoover Dams. The United States uses 6,463 billion kilowatt-hours per year from natural gas, which equals the energy from 1,615 Hoover Dams. (This is also equal to the energy in 5 billion tons of coal, which we discuss in the next chapter.)

Hope in the deep seas

In addition to the conventional sources of natural gas, several unconventional sources may provide large amounts of gas fuels. These sources are gas hydrates, coal-bed methane, and shale-bed methane. As I understand it, these possible sources are part of the “unknown but probable” resources but may even exceed those estimates.

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.