Complementing cheap energy is efficient use thereof. A smartphone today can practically be run off solar energy, where such computing power used to darn near re

Complementing cheap energy is efficient use thereof. A smartphone today can practically be run off solar energy, where such computing power used to darn near require its own major power plant. "3D printed buildings" will construct architecture with much less energy than current building techniques, which in turn are made with much less energy than past all-human-powered construction. There's a baseline of how much energy we each need (lifting building elements into place, caloric food needs, BTUs for thermal comfort in a given enclosed space), with a baseline of what energy is available (1KW/hr per m^2, plus whatever stored energy is available in wood & fossil & nuclear fuels); while there are upper and lower limits, we can use what's available to more efficiently transition one to the other.