The insights of William Stanley Jevons, though set down long ago, make a profound contribution to the current debate over energy efficiency and energy-conservation policy, and not just to the debate over the role of renewable energy in modern society.
Jevons’s The Coal Question (London: Macmillan and Co., 1865) made the case that renewables (windpower; waterpower, biomass, and geothermal) could not substitute for coal. (Jevons underestimated the possibilities of crude oil and natural gas as substitutes for coal, but that is another story.) Thus, coal depletion was an important issue in his day, particularly in the United Kingdom, where domestic coal satisfied all needs and was a major export besides.
Could efficiency come to the rescue, Jevons asked, doing on the demand side what renewables could not do on the supply side?
He answered no. His insight was that improving efficiency in coal’s use would not significantly reduce demand but, in fact, would increase it by enlarging the range of economical uses for coal.
Here is Jevons’s statement of what today is known as Jevons Paradox (p. 103):
It is wholly a confusion of ideas to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth. As a rule, new modes of economy will lead to an increase of consumption, according to a principle recognized in many parallel instances.
And (p. 105):
Civilization … is the economy of power, and our power is coal. It is the very economy of the use of coal that makes our industry what it is, and the more we render it efficient and economical, the more will our industry thrive, and our works of civilization grow.
He gave specific examples to support his conclusion:
In less than one hundred years … the efficiency of the engine has been increased ten- or fifteen-fold; and it need hardly be said that it is the cheapness of the power it affords that allows us to draw rivers from our mines, to drive our coal-pits in spite of floods and quicksands, to drain our towns and lowlands, and to supply with water our highest places; and, finally to put in motion the great system of our machine labour, which may be said, as far as any comparison is possible, to enable us to do as much as all the other inhabitants of the world together could effect by their unaided labours (p. 108).
The reduction of the consumption of coal, per ton of iron, to less than one-third of its former amount, has been followed, in Scotland, by a ten-fold total consumption, not to speak of the indirect effects of cheap iron in accelerating other coal-consuming branches of industry (p. 114).
Jevons was not the first to realize that the sum of energy usage could grow from improved efficiency, even if an individual application might require less. Jevons (p. 107) quoted C. W. Williams, who wrote in The Combustion of Coal (1841, p. 9):
The economy of fuel is the secret of the economy of the steam engine; it is the fountain of its power, and the adopted measure of its effects. Whatever, therefore, conduces to increase the efficiency of coal, and to diminish the cost of its use, directly tends to augment the value of the steam-engine, and to enlarge the field of its operations.
Expect improving technology to reduce energy use per application. But don’t expect total demand to fall. What Thomas Edison said a century ago remains true:
I am ashamed at the number of things around my house and shops that are done by animals—human beings, I mean—and ought to be done by a motor without any sense of fatigue or pain. Hereafter a motor must do all the chores. (Edison in 1910, quoted in Theresa Collins and Lisa Gitelman, Thomas Edison and Modern America. New York: Bedford/St. Martin’s, 2002, p. 60.)