Forgotten Fundamentals of the Energy Crisis - Part 11
by Prof. Al Bartlett
XI. A postscript for science teachers
For decades physics teachers throughout the world have discussed the RC circuit and the decay of radioactive atoms and have thus introduced the simple differential equation that gives rise to exponential decay of the charge on the capacitor or of the number of remaining radioactive nuclei. These provide a wonderful opportunity for us to digress and to point out that exponential arithmetic has great value outside of these two special examples in physics and to show our students that exponential arithmetic is probably the most important mathematics they will ever see. It is especially important for students to see how the change in the sign of the exponent can make an enormous difference in the behavior of the function. But we will need to do more. We must integrate the study of energy and of the exponential arithmetic into our courses as has been done, for example, in one new text.44 In addition, we have an even larger task. As science teachers we have the great responsibility of participating constructively in the debates on growth and energy. We must be prepared to recognize opinions such as the following, which was expressed in a letter to me that was written by an ardent advocate of "controlled growth" in our local community: "I take no exception to your arguments regarding exponential growth. I don't think the exponential argument is valid on the local level."
We must bring to these debates the realism of arithmetic and the new concept of precision in the use of language. We must convey to our students the urgency of analyzing all that they read for realism and precision. We must convey to our students the importance of making this analysis even though they are reading the works of an eminent national figure who is writing in one of the world's most widely circulated magazines. (The emphasis in the following quotations is in the original.)
The simple truth is that America has an abundance of energy resources... An estimated 920 trillion cubic feet of natural gas still lies beneath the United States. Even at present consumption rates, this should last at least 45 years... About 160 billion barrels of oil still lie below native ground or offshore. That's enough to last us into the next century at present rates of consumption.45
When students analyze these statements they can see that the first statement is false if "abundance" means "sufficient to continue currently accepted patterns of growth of rates consumption for as long as one or two human lifetimes." An evaluation of the second and third statements show that they are falsely reassuring because they suggest the length of time our resources will last under the special condition of no growth of the rates of use of these resources. The condition of no growth in these rates is absolutely contrary to the precepts of our national worship of growth. It is completely misleading to introduce the results of "no growth:" unless one is advocating "no growth."
If it is true that our natural gas reserves will last 45 yrs. at present rates of consumption ( R / r0 = 45 yrs.), then Eq. (6) shows that this amount of gas would last only 23.6 yrs. at an annual growth rate of 5% / yrs., and only 17 yrs. at an annual growth rate of 10% / yrs.. When the third statement is analyzed one sees that the given figure of 160 x 109 barrels of reserves is roughly 60% larger than Hubbert's estimate. This amount would last 49 yrs. if oil was produced at the 1970 rate of 3.3 x 109 barrels / yrs., held constant with no growth. However, our domestic consumption is now roughly twice the rate of domestic production, so this amount of oil would satisfy domestic needs for only about 25 yrs. if there was no growth in these domestic needs. If R / r0 = 25 yrs., then Eq. (6) shows that this amount of oil would last only 16.2 yrs. if production grew 5% / yrs. and only 12.5 yrs. if it grew 10% / yrs..
We can conclude that the author is probably advocating growth in the rate at which we use fossil fuels from the following imprecise statement, "The fact is that we must produce more energy." Therefore the author's statements about the life expectancy of resources at current rates of use are irrelevant. When they are offered as reassurance of the lack of severity of our energy problem they are dangerously and irresponsibly misleading.
Students should be able to evaluate the same author's statement about coal, "At least 220 billion tons of immediately recoverable coal - awaits mining in the United States." This "could supply our energy needs for several centuries." Students can see that the size of the coal reserves given by the author is significantly smaller than either of the two estimates given by Hubbert. They can see that it is imprecise and meaningless to suggest how long a resource will last if one says nothing about the rate of growth of production. In addition to encouraging our students to carry out their responsibility to analyze what they read, we must encourage them to recognize the callous (and probably careless) inhumanity of a prominent person who is perhaps in his fifties,45 offering reassurance to younger readers to the effect, "don't worry, we have enough petroleum to last into the next century," The writer is saying that "There is no need for you to worry, for there is enough petroleum for the rest of my life." Can we accept the urgings of those who advocate unending expansion and growth in the rates of consumption of our fossil fuel resources and who say "Why worry, we have enough to last into the next century."
We must give our students an appreciation of the critical urgency of evaluating the vague, imprecise, and meaningless statements that characterize so much of the public debate on the energy problem. The great benefits of the free press place on each individual the awesome responsibility of evaluating the things that he or she reads. Students of science and engineering have special responsibilities in the energy debate because the problems are quantitative and therefore many of the questions can be evaluated by simple analysis.
Students must be alert not only to the writings in the popular press but to the writings in college textbooks. In the bookstore of a school of engineering I purchased a book that was listed for one of the courses, possibly in political science. Here are a few interesting statements from the book:46
Our population is not growing too rapidly, but much too slowly... To approach the problem ("the population scare") from the standpoint of numbers per se is to get the whole thing hopelessly backward... Our coal supply alone, for example, is sufficient to power our economy for anywhere for 300 to 900 years - depending on the uses to which it is put - while gas and oil and coal together are obviously good for many centuries... So whatever the long-term outlook for these energy sources, it is obvious (that) natural shortage cannot account for the present energy crunch.
Dr. Hubbert, speaking recently, noted that we do not have an energy crisis, we have an energy shortage. He then observed that the energy shortage has produced a cultural crisis. (See Fig. 7.)
We must emphasize to our students that they have a very special role in our society, a role that follows directly from their analytical abilities. It is their responsibility (and ours) to become the great humanists.
Note added in proof:
Two incredible misrepresentations of the life expectancy of U.S. coal reserves have been called to my attention recently. Time (April 17, 1978, p.74) said:
Beneath the pit heads of Appalachia and the Ohio Valley, and under the sprawling strip mines of the West, lie coal seams rich enough to meet the country's power needs for centuries, no matter how much energy consumption may grow." (Emphasis added.)
In reply to my letter correcting this, Time justified their statement by saying that they were using the Citibank estimate of U.S. coal reserves which is larger than the estimate used by Hubbert.
A beautiful booklet, "Energy and Economic Independence" (Energy Fuels Corporation of Denver, Denver, 1976) said: "As reported by Forbes magazine, the United States holds 437 billion tons of known (coal) reserves. That is equivalent to 1.8 trillion barrels of oil in British Thermal units, or enough energy to keep 100 million large electric generating plants going for the next 800 years or so." (emphasis added) This is an accurate quotation from Forbes, the respected business magazine (December 15, 1975, p.28). Long division is all that is needed to show that 437 x 109 tons of coal would supply our 1976 production of 0.665 x 109 tons per year for only 657 years, and we probably have fewer than 500 large electric generating plants in the U.S. today. This booklet concluded, "Your understanding of the facts about "energy and economic independence' issue is of great importance."
A very thoughtful comment on fusion was made to me recently by a person who observed that it might prove to be the worst thing that ever happened to us if we succeed in using nuclear fusion to generate electrical energy because this success would lead us to conclude that we could continue the unrestrained growth in our annual energy consumption to the point (in a relatively few doubling times) where our energy production from the unlimited fusion resource was an appreciable fraction of the solar power input to the earth. This could have catastrophic consequences.
Richard Stout, columnist for the New Republic, noted (Time, March 27, 1978, p.83) that in America, "We consume one third of all the energy, one third of the food and enjoy one half of the world's income. Can a disparity like this last? I think that much of the news in the next 50 years is going to turn on whether we yield to the inevitable graciously or vindictively."
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