The paper he links to compares different scenarios for building and placing wind turbines, looking at actual turbines built in Germany and Brazil. For example, building in the region the turbine's to be set up with recycled steel melted in a furnace powered by hydroelectricity is different to building with new steel in a furnace powered by coal and then shipping it across the world.

Thus old_europe's comment above,

I would say the highest energy investment is in making the steel, which is done exclusively by burning coal.

is true, but not precisely true; steel is almost always made originally with coal, but you can use mostly recycled steel to make things, and for that you need great heat - which doesn't have to come from coal. (For interest, it seems that the rotors cost about as much energy to make as the tower, but the nacelle is most of all.)

And then where you place the thing makes a big difference, if one place gets twice the wind of another, it has half the energy payback period.

My check:-

Worst annual output = 881,972kWh = 3,175 GJ
Best annual output = 3,558,926kWh = 12,812 GJ

Highest embedded energy = 13,797 GJ
Lowest embedded energy = 6,289 GJ

Highest embedded energy / worst annual output = 13,797 / 3,175 = 4.35 years energy payback time
Lowest embedded energy / best annual output = 6,289 / 12,812 = 0.49 years energy payback time, or about 6 months.

The best payback time is for turbines constructed largely of recycled materials in Brazil and used there; the worst for those constructed of new materials in Germany and shipped to Brazil.

The German-Brazil report phil harris linked to complicates matters somewhat by not reporting turbine weight, and by discussing different models without specifying all the differences. We get heights of 45-65m, and foundation masses of 132.7-185.8t.

There was a Danish study of turbines constructed and used in Denmark, which gives figures of
- 3,169 GJ for construction and maintenance over 20 years
- 522 GJ for scrapping after 20 years
+ 733 GJ recovered from materials
or 2,958 GJ net.

Note that these figures are about half the German and Brazilian ones.

This all leads to an energy payback period of 3-4 months.

The Danish report notes,

During the past ten years the weight of Danish wind turbines per kW nameplate electrical power has been halved. That obviously contributes significantly to energy balance improvement.
Danish 600 kW wind turbines on average weigh approximately 60 metric tonnes plus 4.5 tonnes weight for the rotor blades.

A comparable German 600 kW Tacke turbine weighs some 90 tonnes plus 4.5 tonnes of rotor blades. If we account for differences in tower height, and look at turbines with 50 metre tower height only, it would appear that Danish turbines weigh one third less than the German turbine.

So while phill harris' calculations were good, what must be borne in mind is that apparently the Germans, despite their reputation, are not terribly efficient - at least not with wind turbines :) Go with the Danes!

Lastly, given that a barrel of oil is about 6GJ, if we used nothing else to produce the energy required to make one of 500-600kW wind turbines above, that would be about 500bbl for the Danes, and 1,000-2,000 for the Germans. So we can say 1,000-4,000bbl oil per MW, if no other energy inputs were used. Or 3,000-12,000bbl/MW if we assume all the energy comes from burning oil in some furnace for electricity or just the heat (don't know why you'd do that when you can get electricity and heat from more efficient sources, but still).

But of course, at present oil is only required for the machinery to mine the ores, and that to transport, erect and maintain the turbines. So the actual oil use would be fairly trivial, I'd say.

Bear in mind that over the past quarter-century total electricity generation has risen IIRC some 3% annually. So already we're spending a lot of money, time and effort building new power plants.

I'm confused as to why building (say) a coal-fired plant, nobody worries about the costs or resources or energy required, but building (say) a wind turbine, suddenly doom is upon us, we'll all go broke, think of all the steel you need, etc. If we can build terawatts of coal or gas each year, I don't see why we can't build terawatts of wind or solar or whatever.