Use the total solar energy data in the ppt Ch2 that reaches the Earth to calculate how many USs can the solar energy sustain in terms of power (see the ppt Chl) if we consider a 20% conversion. Estimate what population this amount of solar power sustains if everyone lives in an American standard (hints: use US annual E consumption in 2015 as example, and use population and US fractions in 2011 as example, see the ppt CH1 slide 4-5).