feb 20, 1940 - Fortune Magazine article, RB Fuller uses term 'energy slave'
An energy slave is used to compare the productivity of a person and the energy that would be required to produce that work in the modern, oil fuelled industrial economy, although it could be applied anywhere that labor is produced with non-human sourced energy. It does not include the ancillary costs of damage to the environment or social structures. Formally, one energy slave produces one unit of human labor through the non-human tools and energy supplied by the industrial economy, and therefore 1 ES times a constant that converts to work accomplished = 1 human labor unit.
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