I just wrote: "The 20 km^2 (2x10^7 m^2) greenhouse proposed at the base can at 100 percent efficiency provide only 20 MW of solar power." Wow, was I wrong, by a factor of 1000. The solar insolation factor is 1 kW/m^2, not 1 W/m^2. A 100 percent effecient solar collector with 2x10^7 m^2 operating in ideal overhead sun conditions would collect 20,000 MW. Still, it is interesting that, on average, the solar collector seems to not be needed if the tower is tall enough.
Regards, Horace Heffner
