Friday, November 13, 2009

Wind Electricity Generation

A compendium of facts collected from a wide variety of sources, and my inferences therupon.

The top two commerical wind turbines, by market share:
1 Vestas 22.8 V90 Geared 3,000 kW
2 GE Energy 16.6 2.5XL Geared 2,500 kW
(source):http://www.wind-energy-the-facts.org/en/part-i-technology/chapter-3-wind-turbine-technology/evolution-of-commercial-wind-turbine-technology/large-commercial-wind-turbines.html
[note that the figures of 3,000 and 2,500 are the nameplate capacities of those turbines.]

"Capacity Factor: Wind power typically has a capacity factor of 20-40%"
(source):http://en.wikipedia.org/wiki/Intermittent_energy_source
What this means is, that the nameplate capacity on a wind turbine is the maximum amount it can generate in ideal wind conditions.
The capacity factor is the percentage of its nameplate capacity to expect over a long period of changing conditions.

the installation cost:
"I asked the company Vestas this question. They are number two in the world in producing wind turbines. They told me the answer is based on a thousand factors but that the general rule of thumb is that wind turbines cost 1.3 to 1.5 million per megawatt. "
http://wiki.answers.com/Q/How_much_does_a_3MW_wind_turbine_cost

USA electrical generation, by source, for 2008:
coal: 1,994,000,000 mWh
NG: 877,000,000 mWh
nuclear 806,000,000 mWh
(source):http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html

"The American Wind Energy Association has reported that wind projects installed through the end of 2008 were expected to generate 52 million megawatt-hours/year (MWh/yr),"
(source):http://en.wikipedia.org/wiki/Wind_power_in_the_United_States.

Okay, now its time for one inference from me.
This is a mere calculation:
If anyone has a stated goal of replacing all of the existing coal-fired electricity generation in the USA
(and assuming, for the moment, that electricity demand does not increase),
2,000,000,000 mWh divided by 8500 hours/yr is about 250,000 mWyr.
250,000 of the largest commercial wind turbines.

If they cost \$3 million each, as above, thats a total of \$750 billion, or roughly the budget of DOD.
And, after building them, you have to find someplace to put them. Not in my backyard, please.

tomorrow lets look a little closer at coal.

addendum, Nov. 21

I just have to wonder ...
how much coal has to be burned (in blast furnaces) in order to fabricate one large wind turbine.
I imagine that its not insubstantial. There is still no other way to make steel....