Suppose, for the sake of analysis, that these quantities can be replaced by the average values in a few discrete strata. Then, the system I used in Chapter 2 of On the Preservation of Species can be resurrected mutatis mutandis for our purposes. It will not be necessary to take advantage of the distinction between personal emergy budget and work-related emergy budget until we begin to furlough people whose work is unnecessary to the well-being of the community. At this point we may employ the notion of the Autonomous Alternative Energy District (AAED):
Nothing is imported from outside the District whereas energy and only energy is exported. If a man needs a car to drive from his home (in the District) to his job (in the District), the car is built, maintained, and fueled in the District. If his wife is sick the doctor in the District will treat her with medicine made in the District from chemicals produced there from raw materials mined there and subsequently recycled aggressively. The ERoEI of the new energy technology is the total energy produced, ER, divided by the quantity ER minus the quantity EX, where EX is the energy exported; i. e., EX = ER – EI. If the District is able to export any energy at all the ERoEI ratio exceeds one and the technology is feasible – at least. In the case of a single energy technology, the energy produced by each technology can be assigned a transformity of unity and the value of emergy is quantitatively the same as the Gibbs availability, which, at room temperature, is the Gibbs free energy. I prefer to report emergy values in units of emquads rather than quads, emjoules rather than joules, etc. Thus, the units of transformity are emquads per quad, for example.