To begin our sustainable design for the earth, we might ask how much energy does it take to support one person living like the average American using current processes.
Using the average American is arbitrary. We could use someone less consumptive or more consumptive but it is safe to say that the average person on the global does not want to live less well than the average American.
Not counting the thermal or photosynthetic energy that US citizens get without effort from sunlight; counting only the energy that humans expend effort to obtain, Figure 1, shows the US population consumes 97.4 quadrillion BTU's (15 zeros) of energy.
Figure 1
If we divide that energy by the 306 million people who live in the US, each requires 318 million BTU's to support themselves. That is a little over 90,000 Kwh per year.
