Section II – Forecasting America’s Energy Needs in 2100
While politicians may wish to speak in generalities, engineers prefer to express our thinking quantitatively. Fortunately, the critical issue of planning for America’s energy needs in 2100 easily lends itself to being defined quantitatively. In fact, it is a matter of simple arithmetic. The two important pieces of information needed to forecast America’s energy needs in 2100 are the size of the population and the expected energy supply needed per person (per capita) each year to maintain a prosperous standard of living.
A. America’s population will likely more than double by 2100
America’s demand for natural resources is driven by its population size. Over the last two centuries, America’s population has climbed steadily from around 5-8 million in 1800 to around 307 million in the last census in 2010 (Fig. 2).
In 1999, the U.S. Census Bureau made several forecasts of the U.S. population through 2100. Figure 3 shows three of these forecasts establishing an upper ❶, a lower ❷, and a middle ❸ series projection based on assumptions of fertility and death rate, along with continued immigration. Of these three forecasts, the middle series is used in this paper as the basis for projecting American population size in 2100.
In 2008, the Census Bureau updated the 1999 projection through 2050. This is shown in Fig. 4. Using this update, a linear extrapolation is then used to establish a ballpark estimate of the 2100 U.S. population size of 625 million used in this paper. As seen in Fig. 4, this is about 60 million greater than the 1999 forecasted 2100 population, indicating that, as the century unfolds, even this 625 million forecast may prove conservative—a point to keep in mind!
With a planning estimate of 625 million Americans in 2100 as the starting point, the next step in assessing White’s Law is to examine U.S. per capita energy use.
[Author’s note: For updated projections of the U.S. population in 2100, please see the 2015 paper Becoming Spacefaring: America’s Path Forward in Space. The 2100 estimate was revised to 617.5 million based on the most recent information available. The difference, however, is minor and does not impact the information presented in this paper.]
B. Per White’s Law, American culture is quantitatively defined by its per capita energy use
At the heart of the American industrial revolution of the later 19th century was the expenditure of increasing amounts of energy per person (per capita) to make life better. In a general sense, per capita energy use is a good quantitative measure of our culture or standard of living since, by White’s Law, they are related.
To discuss per capita energy use, we need a readily understandable unit of measure. For this paper, the barrel of oil equivalent or BOE is this unit. An actual barrel of oil contains 42 U.S. gallons. By international agreement, this amount of oil is assumed to contain 5.8 million British Thermal Units or BTUs of energy.
1 BOE = 5.8 million BTU
All forms of energy production or consumption can be expressed in terms of the BOE of gross thermal energy produced or consumed. This is true even for production methods such as hydroelectricity that do not involve any form of combustion. In such cases, the actual electrical energy generated is replaced by the amount of oil that would be required to generate the same quantity of electrical energy using an oil-fired power plant.
The U.S. Government has kept reasonably good energy production and consumption statistics since the 1850s. By summing up the types of energy produced, converting this to the common unit of BOE, and then dividing by the U.S. population at the time, an historical per capita energy use, expressed in BOE/yr., can be determined. The calculated annual U.S. per capita energy use from 1850-2010 is shown in Fig. 5.
Up until the Civil War, non-food per capita energy consumption was primarily for cooking and space heating. The 17 BOE/yr. of per capita energy consumption was almost entirely from wood fuel—around five cords of seasoned hardwood per person per year. While there was a modest amount of steam-powered transportation and industry, prior to the Civil War this did not significantly impact per capita energy use. For example, in 1850 there were only about 9,000 miles of railroad. Also, during this mid-century period, building construction and heating technology (T) improved, especially with the introduction of cast iron stoves to replace open hearths for cooking and heating. This increased the efficiency of the use of wood fuel, allowing more work to be performed per cord of wood fuel.
The impact of the American industrial revolution began to be reflected in increased per capita energy use about 1890 as the nation shifted from wood fuel and human/animal power to steam-powered transportation and industry; to electricity generation; to coal, oil, and natural gas fuels; to oil-fueled transportation; and to electricity-powered communications, entertainment, homes, and industry. As seen in Fig. 5, with the exception of the Great Depression, per capita energy use climbed fairly continuously from 1900 until the early 1970s—rising from about 22 BOE/yr. in 1900 to the historic peak of about 62 BOE/yr. just prior to each of the two oil supply crises of 1973 and 1979.
C. Despite 30 years of intense emphasis on conservation, American’s per capita energy use has only very modestly declined
To forecast the average U.S. per capita energy need in 2100, a baseline representative of the future American culture is needed. The period of 1960-2010—roughly the last half-century—is used. This covers the period of the rapid rise in per capita energy use during the 1960s, the peak in domestic oil production in 1970, the twin historic peaks in the 1970s, the two oil crisis-induced economic recessions, the subsequent two decades of a very modest decline in per capita energy use, and the beginning of the current recession. It was during this half century that the modern American lifestyle was established—a lifestyle that, it is presumed, Americans in 2100 will wish to continue if not improve.
Figure 6a shows the total annual gross thermal energy used over the last half century more than doubling from 8 billion BOE/yr. in 1960 to nearly 18 billion BOE currently. The key point of this figure is emphasizing the fact that the U.S. total energy consumption continued to increase at a fast pace despite, as seen in Fig. 6b, a leveling off and modest decline in per capita energy use. This emphasizes the major influence of population size in defining America’s energy needs in the future.
The chart of U.S. per capita energy use over the last 50 years, seen in Fig. 6b, is a remarkable example of a civilization adapting to circumstance. Imagine it is still the early 1970s and you are plotting per capita energy use since 1900 in order to forecast America’s energy needs in the 21st century. What would you have forecast for 2010? A simple linear extrapolation would put per capita energy use somewhere in the range of 100-120 BOE/yr. The United States would today be annually consuming about 31-37 billion BOE. Given the standard of living Americans have today at about 58 BOE/yr., it is difficult to visualize what standard of living would need 100-110 BOE/yr.—flying cars, perhaps? The point of this thought exercise is to appreciate the fundamental transformation that America underwent in the 1970s and 1980s as the near-continuous century-long growth in annual per-capita energy use halted, leveled off, and then began a modest decline.
The twin oil-supply crises of the 1970s obviously triggered this transformation. The severity of the back-to-back recessions, the increased energy costs, the accompanying inflation, the imposition of Government mandates with new energy efficiency standards (e.g., car mileage), and, especially, the emergence of new technologies ended the pre-crisis year-over-year growth in per capita energy use. In effect, Americans became content with the standard of living they had achieved by 1980 and, going forward, were content to let technological improvements, rather than increased per capita energy use, achieve future increases in their standard of living. In essence, Americans made White’s Law work for them, instead of against them. Of course, it helped immensely that the United States had affordable replacement energy sources to turn to.
The historic peak of U.S. per capita energy use occurred in 1979. After that, the United States has seen a modest long-term decline in per capita energy use even during prosperous times. While many in the environmental movement had advocated for significant reductions, the reality is that over the nearly thirty-year period of 1979 to 2007, per capita energy use declined only a total of a 6%. Obviously, there has been an improving energy efficiency technology component of White’s Law responsible for part of this reduction, e.g., car mileage standards. However, there are also social and consumer trends of an aging population, more single households, larger homes, longer commutes, more electronic communications, larger TVs, a higher standard of living at the lower end of the economic spectrum and during retirement, etc., which also have impacted per capita energy use.
The very important historical lesson learned from these past 30 years is that despite significant government and societal emphasis on achieving substantial decreases in per capita energy use through energy conservation and technological energy utilization efficiency improvements, the actual real reduction in per capita energy use was only about 0.2% per year. It strongly argues against the proposition that America can be expected voluntarily to “conserve” its way out of the pending energy crisis absent draconian Government mandates.
D. U.S. per capita energy need in 2100 is forecast to be 50 BOE/yr.
Drawing on the last 30 years’ data, in Fig. 7, the author linearly extends the 1979-2007 trend to 2100, where the U.S. per capita energy use would be in the ballpark of 50 BOE/yr. This equals a 14% reduction from the current U.S. per capita non-recession energy use of about 58 BOE/yr. Accomplishing this modest decline would be expected to come from technological advancement with no loss of standard of living—making White’s Law work for us. This means that our grandchildren living in 2100 would live in homes comparable to ours today, have personal transportation comparable to ours today, travel for business and vacation, etc. Of course, there would twice as many Americans, meaning that housing and roads would double, food and water production would double, etc.
For comparison, the U.S. Energy Information Administration (EIA) 2013 projection of U.S. per capita energy use through 2040 is also shown in Fig. 7. This EIA projection reflects a number of separate inputs including increased environmental regulation and a decreased long-term rate of economic growth. While the author’s linear projection would see a 55 BOE/yr. rate of consumption in 2040, the EIA is forecasting only 46 BOE/yr.—16% lower.
Recall that the total reduction from 1979-2007 was only about 6%. Also, take note of the fact that this EIA projection begins at the current depressed mid-recession per capita energy use and forecasts a permanent, long-term decline from this depressed starting point. Compare this to the experience after the 1979-1985 recession—Fig. 6b—when, as the economy and consumer confidence improved, per capita energy use returned to near-historic peak levels. No such recovery is seen in the EIA forecast as the economy recovers. Hence, the author believes the EIA forecast to be unreasonably optimistic—yes, optimistic—for use in projecting U.S. energy needs through 2100 because projections of future total U.S. energy needs, based on this EIA forecast, are likely to be low. Energy security planning would then miss the mark in terms of having adequate future energy supplies. Draconian government mandates may then be necessary to force lower per capita consumption to meet the inaccurate forecasts and correspondingly inadequate energy supplies.
At the author’s forecast per capita energy use of 50 BOE/yr. by 2100, U.S. per capita energy use would have declined by nearly 20% from the 1970s historic peak. While more energy conservation may be achievable, it is also important to recall, as noted earlier, that the future population size projection is now trending higher, meaning that the United States may actually have more than 625 million people in 2100. Thus, the 50 BOE/yr. per capita energy use and the 625 million U.S. population in 2100 combine to provide, at least for now, a reasonable set of assumptions for assessing future U.S. energy security needs. Adjustments, of course, will be necessary as the future unfolds.
E. The United States will need about 31 billion BOE annually by 2100 to maintain its standard of living
The calculation of the U.S. energy need any particular year is simple:
Population size x per capita energy use = total energy needed
Using the population growth data shown earlier combined with the linear decrease in per capita energy use to 50 BOE/yr. forecast for 2100, the annual U.S. energy need from 2010-2100 can be computed.
625 million x 50 BOE/yr. = 31.25 billion BOE/yr. in 2100
The annual need from 2011-2100, plotted in Fig. 8, will grow by nearly 75%. While this increase sounds large, as noted earlier, the U.S. total energy consumption more than doubled in the last half-century. Thus, planning for a U.S. energy infrastructure capable of supplying in the ballpark of 31 billion BOE by 2100 is prudent.
F. From 2011-2100, the United States will need a secure supply of 2.23 trillion BOE
Figure 9 shows the cumulative energy use and projected future need from 1850-2100. From 1850-2010, the United States consumed just shy of 1 trillion BOE. From 2011-2100, the forecast is that the United States will need an additional 2.23 trillion BOE. Hence, through the remainder of this century, the United States will need more than twice the amount of energy consumed since 1850.
For U.S. energy security planning purposes, there are now two targets that must be met to ensure energy security and economic prosperity:
- An annual energy supply growing to about 31 billion BOE per year by 2100.
- A total energy supply of about 2.23 trillion BOE through 2100.
Of course, remember that the U.S. energy needs do not simply end in 2100. These targets are, essentially, intermediate planning milestones.