The concept of an energy slave originated with Buckminster Fuller in 1944. Using data from the United States, German, and Swiss armies, he calculated that the amount of work a person can produce in a year was equivalent to 37.5 million foot-pounds per year. Now a foot-pound corresponds to 1.355818 joules, therefore the energy output of an energy slave was 50.843 million joules a year.

So how many energy slaves do we employ every year. Fuller’s approach was to measure the total energy consumed—but he adjusted that figure by taking only 4 percent of it. He assumed that we lose 96 percent of the energy in getting it

*to*work, thus a 4-percent energy efficiency.
The most recent Energy Outlook published by the U.S. Energy Information Administration (link) provides data for the year 2008. In that year world consumption was 505 quadrillion BTUs. Since one BTU equals 1,054.35 joules, that consumption is 532,447 quadrillion joules. Let us take 4 percent of that, as Fuller did. We get 21,298 quadrillion joules. We divide that by 50.843 million joules and get a total count of “energy slaves”: 418.9 billion of them. We divide that by the world population (6,973,738,433), and, Presto! We learn that each living human being is served by 60 more or less invisible energy slaves.

Fuller’s calculations were applied to data for 1950. In that year (the population was then 2.25 billion), the result was 38 energy slaves per capita.

Something to think about. You will find other numbers on the Internet. They are sometimes quite hokey, based, for instance, on calorie intake by humans. Here we stick with the concept’s inventor. If you don’t like the “low” number, you can make the assumption that our overall energy efficiency is higher than 4 percent. But understating something is not always harmful. Our dependence on this modern form of slavery is quite overwhelming enough when we consider sixty servants at our personal beck and call.