A diagram (Ѻ) by Jennifer Barker (2006) who estimates that the average person sues 129,000 horse-power hours of electricity, which translates to 147 energy slaves working continuously, 24-hours a day.
In terminology, energy slave is an abstract conception referring to the technologic-mechanical energy equivalent that a healthy human youth could do.  The lifestyle of any person, in this logic, can be equated with a certain number of “energy slaves” equivalent to the number of human laborers required, measured in human labor power energy units, to mediate that person’s way of life.
Etymology In circa 1944, American philosopher Buckminster Fuller introduced the term "energy slave".  Fuller proposed the term based on the average output of a hard-working man doing 150,000 foot-pounds of work per day and working 250-days per year. 
In 1954English thermodynamicist Alfred Ubbelohde, in his book Man and Energy, was using the term, it seems, independent of Fuller. 
It has been estimated, for instance, that a middle-class American lives a style of life that is equivalent to the work produced by 200 human slaves.  Fuller, who believed that in the future human societies would come to rely mainly on renewable sources of energy, such as solar-power and wind-derived electricity, referred to Americans as possessing two-hundred “energy slaves” that run on nonrenewable resources.  One energy slave, according to Fuller, equals “each unit of one trillion foot pound equivalents per annum consumed annually by respective economies from both import and domestic sources, computed at 100% of potential content.” 
Derivation Fuller used data gathered by the U.S., German, and Swiss armies to arrive at an estimate for the average amount of (mechanical) work a person could do in a year. This is in addition to the energy spent in metabolic self-maintenance. The net work done constitutes a net "advantage" in dealing with the environment. A figure of 37.5 million foot-pounds was arrived at. 
Using this logic, one can calculate the ratio of work done by a system to the energy intake, to obtain a measure of efficiency. Since many machines and appliances inefficient, Fuller posited a figure of 4% overall efficiency for total energy consumption. He then calculated world energy consumption for the year 1950 as being 80.17 quintillion foot-pounds (plus or minus 10%). Given only 4% efficiency the net work obtained equaled 3.2 quintillion ft-lbs. One can divide this figure by the net annual energy output per man of 37.2 million ft-lbs. This gives a result of 85.5 billion man-year equivalents done by machines. These man-year equivalents are energy slaves. 
If the number of energy slaves is divided by the world population total of 2.25 billion (1950) a figure of 38 energy slaves per person is arrived at. Fuller plotted the geographical concentrations of energy slaves on what he called his World Energy Map. 
In 1987 commentary on Fullers energy slave theory, author Stephen Boyden commented that "in the USA, the daily use per capita of energy is around 1000 MJ; that is, each person has the equivalent of 100 energy slaves working 24 hours a day for him or for her.... In some developing countries, the rate of energy use is less than the equivalent of one energy slave per person." 
References 1. Fuller, Buckminster. (1972). Utopia or Oblivion: The Prospects for Humanity, (pg. 151). Bantam Books. 2. Marks, Robert W. (1964). Space, Time, and the New Mathematics, (pg. 269). Bantam Books. 3. Ward, Barbara. (1976). The Home of Man, (pg. 49).New York: Norton. 4. Rifkin, Jeremy. (1989). Entropy: Into the Greenhouse World (revised edition), (pg. 151). New York: Bantam. 5. Buckminster, Fuller, Krausse, Joachim, Lichtenstein, Claude. (2001). Your Private Sky: Discourse. Springer. 6. Energy Slave – Nous.org.uk. 7. World Energy Map – Nous.org.uk. 8. Boyden, Stephen. (1987). Western Civilization in Biological Perspective: Patterns in Biohistory, (pg. 196). Oxford University Press. 9. Caplow, Theodore and Hicks, Louis. (2001). The First Measured Century: An Illustrated Guide to Trends in America, 1900-2000. (pg. 256). American Enterprise Institute. 10. Ubbelohde, Alfred René. (1954). Man and Energy: Illustrated (pg. 92-100). Hutchinson's Scientific & Technical Publications.