A typical land-based wind turbine might have a nominal output of 2 megawatts (2 mW). But -depending on location- it will only deliver the full 2 megawatts about 16% of the time. Therefore, it would seem unwise to depend on wind for more than one-sixth of one's power needs.
How many 2,000,000 watt (2 mW) wind turbines would be required to replace just one-sixth of the 12,900,000,000,000 watts (12.9 Terawatts), presently produced from carbon-based fuels every hour here on Earth, assuming that the wind turbines are operating at 16% (0.16) efficiency? And how much would it cost for that many wind turbines?
2,150,000,000,000 watts/(2,000,000 watts per turbine x 0.16) = 6,720,000 turbines
Each turbine costs about $3,500,000 installed.
$3,500,000/turbine x 6,720,000 turbines = $23,500,000,000,000
Excuse me? $23.5 TRILLION dollars????
It's a pretty scary number, but just for future comparison purposes, to eventually put this number into perspective, let's calculate the cost per Terawatt:
$23.5 Trillion/2.15 Terawatts = $10.9 Trillion/Terawatt (remember this number!)
Also, the good locations for wind vary a LOT (see map below). But to be useful, windmills must be located near their potential end users, or near transmission lines that can carry their power to the end users. Or else, expensive new transmission lines must be constructed. More TRILLIONS?
And remember, there are two additional VERY big problems:
1. Windmills only deliver their rated power about 16% of the time: our $23.5 TRILLION dollars in windmill money is only buying us ONE-SIXTH of the power we will need!
2. We will need LOTS of batteries to store power at times when the wind is actually blowing. Opps! Have you priced really big batteries lately? More TRILLIONS? (There may be an answer to this second problem - see smart grid.)