Saturday, April 18, 2015

A simple energy calculation

From http://nextbigfuture.com/2015/04/elon-musk-battery-singularity-1000.html we read: "The US uses 4500 TWh of electrical power (and 10 times that amount when currently non-electric transportation and industrial power usage is counted.)". Presumably per year.
So assume a near future world with 10 billion people with average standard of living and energy use that of the current US, which has 1/3 billion people. Total energy is 4500*10*30 TWh/year, which to one significant figure is 1000000 TWh/year.
In http://withouthotair.blogspot.com.au/2014/08/shale-gas-in-perspective.html we see:


Shale gas padWind farmSolar park
(10 wells)87 turbines,
174 MW capacity
1,520,000 panels,
380 MW capacity
Energy delivered over 25 years9.5 TWh9.5 TWh9.5 TWh
(chemical)(electric)(electric)
Number of tall things1 drilling rig87 turbinesNone
Height26 m100 m2.5 m
Land area occupied by hardware, foundations, or access roads2 ha36 ha308 ha
Land area of the whole facility2 ha1450 ha924 ha
Area from which the facility can be seen77 ha5200-17,000 ha924 ha
Truck movements2900-20,00078003800 (or 7600*)

So these facilities deliver 9.5/25 TWh/year. About 0.4. So we'll need 2.5 million of them. So if we take the "land area of the whole facility" to be 1000ha for wind or solar we get 2.5 billion hectares total.
Now according to google the world land area is 15 billion hectares. So no problem, right?