> Estimates of growth in electric power needs over the next 40 years are in the range of 3.4%/year.That's a doubling time of 21 years, ie 160 tera watts in 63 years

World electric-power generation in 2005 averaged 2 terawatts, not 20 terawatts.
http://www.eia.doe.gov/oiaf/ieo/electricity.html

At 20-fold/century growth (3.04% annual), that 2 terawatts would become 6.4 million terawatts in only 5 centuries. Terrestrial nuclear power can handle this growth. SBSP, because of orbital real-estate limitations, cannot.

I believe you must have msiread that article. Here's a direct quote from that .GOV site.

GAry 7

"World net electricity generation nearly doubles in the reference case, from 17.3 trillion kilowatthours in 2005 to 24.4 trillion kilowatthours in 2015 and 33.3 trillion kilowatthours in 2030 (Table 10).+

I can see the misunderstanding. One is the installed capacity (ie the
amount of generators), the other is the amount generated during the year.
So an installed capacity of 2 Terawatts will over the course of a year
if run 24 hours a day will produce 2 x 24 x 365 Terawatt hours = 17,520
Terawatthours.
Of course they don't all run 24 hours a day, or 365 days a year.

Brett.