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

by Daniel B. Botkin

  Although the preindustrial way to make use of this geothermal energy was to live in sod houses and caves, the modern way is to put long plastic or metal tubes or hoses down a few feet into the earth and spread them out, sometimes vertically, but more commonly horizontally, sometimes over quite long distances (Figure 12.6). During the winter, the temperature of the soils and rocks is a little warmer than the air; in summer it is slightly cooler. The density of the heat energy stored within the upper surface of the Earth is low, but if you bury long pipes and hoses deeply enough, you can gather a lot of energy.

  Figure 12.6 Heat and cooling right under your feet. How a geoexchange system works.24 (Reprinted from National Renewable Energy Laboratory Technical Report, NREL/TP-840-40665)

  Some condominium high-rises in Florida make use of this for air-conditioning. One that I know of uses the cool water a few feet below the surface that maintains a pretty steady temperature of about 67°F throughout the year. Instead of having to use a lot of fossil-fuel energy and standard refrigeration equipment to separate cooler air from warmer air, these systems provide air-conditioning simply by passing water or air through pipes cooled by the groundwater, then pumping this air or water through pipes into the apartments. Farther north, doing just the opposite—pumping colder air or water from a wintry surface down into the ground through pipes and hoses—warms the air and water, which then is circulated in a building to provide heat. The only energy we have to expend to get this heating and cooling is for pumping the air or liquid through the circuit of pipes and hoses, which requires much less energy than heating or cooling air or water with a fuel.

  Because Earth’s soils and rocks are so massive compared with us and our belongings and buildings, vast amounts of geothermal energy exist everywhere on the land (Figure 12.7). This energy is potentially available to us through geoexchange, and indeed an industry is developing to provide geoexchange devices. Proponents say these devices can reduce home heating and air-conditioning bills by as much as 70% and 40%, respectively, although installation costs currently may be about $3,000 more than for a standard air-conditioning and heating system.25

  Figure 12.7 Geothermal energy in the United States. This map shows the potential for the two kinds of geothermal energy: intense heat from volcanic and other earth activity (dark shaded areas) and geoexchange, which uses the solar energy stored in surface and near-surface rocks and soil (the lightest tone). The darker the color, the higher the temperature. (Source: National Renewable Energy Laboratory26)

  The U.S. National Renewable Energy Laboratory estimates that our country could obtain more than 1 million megawatts from geothermal energy, about ten times the amount of energy obtained today from all renewable energy and about 60% of the total energy used today in the U.S. (Figures 12.7 and 12.8).27 Remember, this would be a nonpolluting, nongreenhouse-gas-emitting energy source, whose only potential kinds of pollution would come from the manufacturing of the pipes, hoses, and pumps, whatever that might be. However, installing these systems over the entire land area of the United States would pose many problems, including disruption of parks, nature preserves, and cropland, so it is unlikely that their maximum energy potential will ever be realized.

  Figure 12.8 Wind, solar, and geothermal energy offer vastly greater potential for U.S. energy independence than do fossil fuels, conventional nuclear power, and waterpower. (Source: National Renewable Energy Laboratory28)

  According to the NREL, “Today’s U.S. geothermal industry is a $2-billion-per-year enterprise involving over 2,800 megawatts of electricity generation capacity, about 620 megawatts of thermal energy capacity in direct-use applications such as indoor heating, greenhouses, food drying, and aquaculture, and over 7,300 megawatts of thermal energy capacity from geothermal heat pumps.” The NREL also says that “U.S. geothermal generation annually offsets the emission of 22 million metric tons of carbon dioxide, 200,000 tons of nitrogen oxides, and 110,000 tons of particulate matter from conventional coal-fired plants.”

  About half of the energy used in a typical American home is for heating and cooling, so a transition to local geothermal could result in a significant reduction in energy use with no change in lifestyle or comfort (Figure 12.9). And of course, this would result in a great decrease in the production of carbon dioxide.

  Figure 12.9 U.S. energy use by type. (Source: Energy Information Administration, Annual Energy Review 2008)29

  The bottom line

  • Energy-efficient buildings and green building designs are major ways that we can reduce per-capita energy consumption and achieve energy independence without sacrificing the quality of our lives. In many cases, the quality of life will likely actually improve.

  • Geothermal energy is one of our best bets for energy independence and for inexpensive energy. Geoexchange systems can reduce heating bills as much as 70% and air-conditioning bills as much as 40%.

  • Because geothermal energy is locally produced, it also requires fewer expenditures for a national grid, pipelines, or other means of transporting fuels.

  • One estimate is that within the lower 48 states this local geothermal energy could provide an energy capacity of a million megawatts.

  13. Solutions

  All the previous chapters have been leading up to a consideration of what is possible in the future as we transition away from fossil fuels and, in the shorter term, away from petroleum. We’ve now looked at all the available information about potential energy sources and the advantages and disadvantages of each of them. The tendency has been to champion one source as the complete solution, but the answer is unlikely to be as simple as that. To find our way through the complexities, we look at three scenarios that bracket the possibilities and can help us sort through all of them.

  The simple answer to our energy dilemma

  The simple answer to our energy problem is for Americans to learn to live happily using just 6% of our current per-capita energy use (the amount Kenyans use). Present installations of nuclear and hydropower would provide all that the U.S. would need in 2050, even with the population increase forecast by the U.S. Census Bureau. We could stop using all fossil fuels, abandon all attempts to develop alternative sources, and not even try to increase the quantity of energy provided by nuclear and hydropower today. But it’s unlikely that we could learn to live happily on such a severely restricted energy diet—remember, transportation per capita, and energy use per capita, would have to decline.

  That being the case, solving the U.S. energy problem is not going to be simple—it will involve major social, political, and environmental changes.

  Is there an answer we can live with—happily?

  A solution that would likely be acceptable to most of us would allow us to maintain a high standard of living, perhaps not as high as at present, nor as wasteful of energy, but one that on the whole would seem as good to most of us as it is today. Let’s consider several possibilities, focusing on the United States because the data are best; therefore, the necessary points can be made much more clearly and succinctly. It also makes sense to consider possible solutions for the nation that consumes almost one-quarter of the energy used by all the people in the world. For starters, we need to understand the following.

  Maintaining both an ample energy supply and energy independence will involve not one energy source but several, and an integrated system that makes the best use of each kind. Not all the energy sources that we use today or are experimenting with today will be major players.

  We need a renovated and modernized system to transport energy, through a smart grid and by making liquid fuels from the energy in electricity and transporting it through more and better networks of pipelines.

  How to begin

  We can’t abandon petroleum, natural gas, and coal tomorrow. Alternative energy facilities are presently insufficient, nor will they be up to the task by next year, or the year after. So our first step into our new energy future will be a staged withdrawal from our dependence on petroleum. We can
think of 2050 as the deadline for completing our withdrawal from petroleum, because by that year petroleum supplies will be extremely limited and economically impractical if petroleum economists and geologists are correct in their assessments of petroleum reserves. In short, if by 2050 we haven’t done something about it, nature will do it for us in its own way.

  Let’s consider three possible scenarios for the year 2050:

  Scenario 1: Business as usual. The U.S. population grows to 420 million by 2050, as currently forecast by the U.S. Census Bureau, while per-capita energy use remains as it is today, as does the percentage of energy supplied by each source.

  Scenario 2: Per-capita use as usual. The U.S. population grows to 420 million by 2050, and per-capita use remains the same as today, but the energy comes primarily from solar and wind, largely replacing fossil fuels.

  Scenario 3: Alternative energy sources and energy conservation. The U.S. population grows to 420 million by 2050, U.S. per-capita use drops to half the current level (about that of Japan, Great Britain, and Germany), and only a small amount of energy comes from fossil fuel. The question is, which energy source or sources will we have chosen to replace it?

  In discussing Scenario 3, we explore largely replacing fossil fuels with solar and wind, as in Scenario 2. Then we consider whether coal, instead of solar and wind, could replace petroleum and natural gas, and explain why nuclear power, ocean power, and natural gas are not viable as the major alternatives.

  Of course, mathematically there are an infinite number of scenarios that could be considered. I have selected these three to show the range of costs, as a way to begin to think about the energy future. Economists who read this will quite likely tell you that it is difficult to extrapolate costs into the future, because technological changes affect prices in complex ways. I hope that some economists reading this will be motivated to take what I have written here and improve on the forecasts.

  Scenario 1: If America does not change its habits...

  Americans need to reduce their per-capita energy use. Table 13.1 and Figure 13.1 show the amount of energy use in the U.S. in 2007.

  Table 13.1 U.S. Energy Use in 2007*

  Figure 13.1 U.S. energy use in 2007 totaling 29.3 trillion kilowatt-hours. (Source: Energy Information Agency, U.S. Department of Energy)

  According to the U.S. Census Bureau, the population of the United States will reach 420 million by 2050—120 million more people, 40% more than today.1 If each of the 420 million people, on average, continues to use the same amount of energy that the average American uses today, total energy use would increase from 29 to 40 trillion kilowatt-hours, and the energy supply would have to increase by 40%. Oil would have to provide 16 trillion kilowatt-hours, and coal and gas about 9 trillion kilowatt-hours each2 (Figure 13.2 and Table 13.2). If the petroleum geologists and economists are correct, that amount of petroleum will not be economically recoverable by 2050. Natural-gas use would have to increase 37%, which is unlikely, period, and especially unlikely without great environmental damage from the methods that will have to be used to mine enough of it. Add to this that hydropower would have to increase 27%, which is highly improbable—as discussed earlier, hydropower is more likely to decline.3 Conventional nuclear power plants will also not fill the gap in an economically feasible way, if at all, because of the limits of uranium ore.

  Figure 13.2 Scenario 1: U.S. energy use if the population grows by 120 million by 2050 and Americans do not change their habits. Total energy use would increase to 40 trillion kilowatt-hours. According to petroleum geologists and economists, this is an impossible future.

  Table 13.2 Scenario 1: U.S. Energy Use If the Population Grows by 120 Million and Americans by 2050 Do Not Change Their Habits

  This is an impossible future. But it is the inevitable future for those who believe we can continue business as usual. Even the near-term future—looking ahead, let’s say, only to 2012—is beginning to look grim for maintaining adequate energy supplies if we follow a business-as-usual approach while population and demand grow. According to the nonprofit North American Electric Reliability Corporation, by 2012 energy demand will exceed supply in most regions of the United States, meaning that the per-capita standard of living is bound to decline without major new investments in energy-generating plants.4 Major changes in energy supply and construction of major new facilities can no longer be put off in the hope that somehow something will work out “because it always has.”

  No, our future is not going to be business-as-usual. To maintain a high standard of living, remain a major industrial power, and continue to be a major source of all kinds of creativity—in science, humanities, the arts—we have to move away from petroleum. But, you may say, “we shouldn’t have to decrease the amount of energy each of us uses.” Okay, then let’s suppose nobody has to use less energy, but we do have to move away from fossil fuels.

  Scenario 2: Per-capita use unchanged, but reliance changes from fossil fuels to solar and wind

  Suppose Americans don’t lower their per-capita energy use by 2050 but to a large extent abandon fossil fuels, or what’s left of them, and turn to alternative sources of energy. The analysis of all energy sources in the rest of this book can lead you to conclude that the best thing for ourselves and America of 2050 would be a heavy dependence on wind and solar energy. Today those technologies are best prepared to provide abundant energy and the most energy independence, while being the least polluting and best for the environment.

  In this scenario of unchanging per-capita energy use, I assume that by 2050 oil, natural gas, and coal will each provide only 1% of the energy in the U.S.—fossil fuels will not be gone and entirely forgotten, but we will have made a planned transition away them, continuing to use them where they are best suited, such as providing energy for peak demand and when wind and solar are putting less into the grid than is required at that time. I also assume that nuclear and freshwater energy will remain at their 2010 amounts, with no net increase or decrease—meaning that the number of hydroelectric power plants remains exactly the same as today, and that the total energy generated by nuclear power plants is the same as today, although some of the plants operating today will have been decommissioned and a few new ones added. As a result, nuclear’s contribution drops to 5.9% of the energy supplied, and hydropower drops to 2.9%.

  It may be overly optimistic to assume that hydroelectric energy generation will remain at the current level 40 years from now. The U.S. Department of Energy’s Energy Information Administration has projected that conventional hydroelectric generation will actually decline 23% by 2020 because of the removal and breaching of more dams for environmental or other reasons.5 And as I explained in Chapter 4, “Water Power,” it is unlikely that in the future any new major hydroelectric power plant will be built in the U.S. (or any technologically developed nation, for that matter).

  For this scenario, I also assume that oceans, a yet little-tested energy source, will provide just over 2%, based on the potentials discussed in Chapter 8, “Ocean Power.” Ocean energy will begin to play some role, but ocean-energy technology will likely continue to lag solar and wind. A nation intent on expanding ocean-energy use might invest heavily in its research and development, and might boost the contribution above 2% by 2050, but today we have no real basis for planning on that for America.

  I also assume that geothermal energy and biofuels will provide 5% each. This is a rather arbitrary amount, based simply on the idea that these two sources will contribute significantly, but not largely, to the total. As explained in Chapter 12, “Saving Energy at Home and Finding Energy at Your Feet,” low-intensity geothermal is inexpensive and abundant, and I believe its use is bound to increase.

  I have assumed that biofuels will be a minor player for reasons discussed in Chapter 9, “Biofuels.” Right now the most promising sources of biofuels are algae and bacteria, but they are still in early development. Crops grown to produce fuels are either net users of energy (energy sinks rather than
energy sources), or yield very little more than it took to produce them. As a result, I believe that this technology will be disastrous for our nation, using large amounts of water, straining the supply of phosphate fertilizers, and causing large-scale environmental damage while providing essentially no energy benefit. Despite this, my guess is that lobbyists will not fail completely to get some funding for them. Obtaining energy from waste cooking oils and other wastes is more efficient than not doing so and reduces the amount of new energy required to be generated, but it can never be a major percentage of our nation’s energy. We will continue to use firewood, especially where this can be obtained locally.

  As a result of these limitations, wind and solar would have to provide 38% each, or more than 15 trillion kilowatt-hours each, to make up the difference (see Table 13.3 and Figure 13.3).

  Table 13.3 Scenario 2: U.S. Energy Use in 2050 if Per-Capita Use Does Not Change but Shifts to Heavy Reliance on Wind and Solar This table shows the energy production from each energy source if the population increases as forecast by the U.S. Census Bureau, and if coal, oil, and natural gas provide 1% each, nuclear and hydro provide the same quantity as at present, geothermal and biofuels 5% each, and the oceans 2%. Solar and wind split the rest and provide 38% each.