http://gristmill.grist.org/story/2007/2/16/104655/313#30

On dealing with the "capacity factor" talking point.

This is a widely used talking point against wind power.  The  way to deal with it is to compare kwh produced instead of capacity factors.

There is a convenient graph on the  GE wind power site that provides the necessary data.

http://www.gepower.com/prod_serv/products/wind_turbines/en/36mw/36mw_data.htm

It's the "Average energy yield: 3.6 mw" graph.

Find the average windspeed for the area.   For example 8.5 m/s on an offshore platform in the gulf.  That would correspond to 12 million kwh for this 3.6 mw machine.

A 1.37 mw generator operating continuously for one year (8760 hours) would produce 12 million kwh.

A source that runs for 80% of the time, like a coal or nuclear plant (they have downtime for maintenance), would have to be somewhat larger, 1.71 mw.

So to equal the annual kwh output of a standard 1000 mw coal or nuclear plant would take 585 of these 3.6 mw GE machines mounted on the offshore platforms.

 1000 wind machines of this size would equal the output of 1700 mw of coal or nuclear generating capacity.

To get to the 3000 mw generating capacity that was mentioned in  Laurence's link would take slightly larger wind machines than the 3.6 mw GE model.  The blade diameter would need to go from the 104 meters of the 3.6 mw model to around 136 meters.

Not that diificult a task given mass production and installation.

Increasing the scale of the wind machines to around 312 meters  would  increase the power output to equal 25,000 mw of coal or nuclear generating capacity. 

Adding wave power could double that output.

Electric power equivalent to 50 nuclear reactors or coal plants from 1000 offshore wind/wave power installations.  It's sci-fi now, but it doesn't have to remain so.  Communications satelites were sci-fi a few decades back too.

Hurricane protection can be obtained by mounting the wind/wave power installations on floating platforms that are submersible during severe storm  conditions.

The whole electric generating capacity of the US is around 1 million mw.  That would take 20,000 wind/wave power systems of the 312 meter scale.

With conservation saving 40% of current power use, plugin vehicles could be supplied as well, with that same generating capacity.

A mix of offshore wind/wave power, say 5000 installations, and large scale wind on the great plains, say 10,000 units, biogas generation from manure,waste, and garbage used in fuel cell/turbines, and solar cogeneration on every suitable roof space and over parking lots, and natural gas from coal and tar sand reserves used in the same fuel cell/turbines as the fossil fuel emergency backup of last resort. 

I think it's becoming clear that this really is a practical way to go.