Why not blow away Peak Oil?
RobTzu called me in to an interesting thread on LATOC discussing challenges to the notion that we can't save the world from energy decline after Peak Oil. In the thread, we calculated the required cost to replace the current world power usage fully with wind energy. Here was my contribution:
Well, my good calculator went missing at work a few months back, but I'll give it a try anyway :)
Actually, I get slightly different numbers, but your methods are essentially sound:
387.21*10^15 BTU = 4.09*10^20 J = 4.09*10^17 kJ
(reference #4 has an error: it cites 1054 for BTU -> kJ when it should be 1055 for BTU -> J)
For world power consumption for one year:
4.09*10^17 kJ /[(365.25 d)*(24 h/d)*(3600 s/h)] = 1.3*10^10 kW
(I'm not sure what number you used for the total time in the denominator -- perhaps I've made an incorrect assumption here on what you wanted to calculate)
Number of solar arrays = (1.3*10^10 kW)/(20 kW) = 6.5*10^8
Cost = (6.5*10^8)*$6000 = $3.9*10^12 ($3.9 Trillion)
However, I see a problem with using reference 2 for the price: it says that units from 2 kW to 20 kW start at $6000 -- so I think the lower number is for the 2 kW unit. We can either find a different source or use the 2 kW for $6000 (still low, I think), which gives us:
Cost = $39 Trillion
One more factor we're missing: In the first line of your post, Rob, it says that wind turbine power is really half the equivalent coal power effectiveness over the course of a year. So, multiply by 2:
Cost = $78 Trillion
Although this is significantly smaller than the numbers you calculated, the main point is still the same: It is incredibly difficult and expensive to replace the entire world electrical grid with wind energy. Even though the number I calculated is near world GDP, it would take at least a decade to scale up production to produce the required number of wind generators. This is if we commit all our economic resources to the project, including food (as Rob pointed out). And, this still doesn't account for what is required to meet current growth in demand.
Solutions for saving the entire world from living with reduced energy is not possible, even with massive conservation, and even if we develop commercial fusion tomorrow. That said, we can save a lot of people from hardship by a massive redirection of efforts if we start now. However, this won't happen anytime soon -- and the longer we wait, the less we can achive. For now, we need to focus on who each of us can protect with our given resources, and design accordingly.