Considering an economy without fossil fuels, literally built from the ground, then up, we developed several
interactive research models of biointensive farms that use no fossil fuels. Quantifying and summarizing
total human labor–energy input and total caloric energy output, we demonstrate that a successfully designed
farm can produce a positive energy-return-on-investment (EROI) leaving excess caloric energy available for
building economic-community structures (e.g., schools and hospitals).