We live within a vast mechanized economy. Essentially every aspect of our lives is governed by or dependent on machines. Even agriculture, with its connection to the sun and the elements, is highly automated. For every unit of energy you consume in edible form, machines expend ten times as much energy to harvest, process and deliver it to you. In other industries, the ratio of exosomatic (machine) to endosomatic (human) labor is even greater, 100:1 or more.
This quiet transition to a robotic economy raises an interesting question about money. The machines we are dependent on for our survival have no notion of human currency. They are paid, in a sense, and are paid in energy, whether it is electricity or hydrocarbon fuel. They do not work for IOUs. So does it make more sense to define money in terms of energy?
Energy, whether it is banked in the form of oil or water behind a hydroelectric dam, translates into a precise amount of mechanical work, and therefore economic output. The same truck will drive the same distance given the same amount of diesel fuel. Because of this, an energy reserve really is the same thing as money in the bank, except that energy translates directly to mechanical work. It is a more honest basis of accounting for an economy where more than 99% of the real work is done by machines.
This website, along with the essay, The Joule Standard, explores how money based on energy, metabolic currency, would work, and how such a system could be incrementally developed and tested like other emerging technologies.