Wednesday, November 04, 2009

Wind Energy



Recently when driving in Western Illinois near the Iowa border I noticed a vast field of wind turbines off Route 20. On the way back to Chicago I got off the highway and started driving on the rural dirt roads to get a closer look.

These are the wind turbines near Lena, IL. The turbines are part of the "EcoGrove" project. A firm called EcoEnergy was the project manager for this effort, and here is the web site describing the project. The project has a capacity of 100 MW and the turbines are between 1.5 and 2.5MW each... so there are at least 40-50 wind turbines at the site. The project cost $200M (per the web site). Per the wind FAQ's section of their site:
How big is a wind turbine?
EcoEnergy’s turbines typically measure 262 feet (80 meters) to the hub height (where the blades meet) and rotor diameters in the range of 246 to 295 feet (75 to 90 meters)..

As you can see from the photos, these wind turbines are huge. They were all turning slowly the day I was there in the wind, with three blades.
Because they don’t produce all the time, aren’t wind turbines an inefficient way to get our electricity?
Wind turbines actually generate electricity most of the time (65 to 80 percent), though the output amount is variable.

This is a strange question. You are wondering what the total output of wind energy is, and this just answers whether or not the turbine is generating any energy at all.
Wind turbines are actually extremely efficient. One of the simplest ways to measure overall efficiency is to look at the energy payback of an energy technology, or the amount of energy consumed in producing additional energy. The energy payback time for wind is similar to or better than that of conventional power plants. A recent University of Wisconsin – Madison study calculated that the average energy payback of Midwestern wind farms is between 17 and 39 times as much energy as they consume (depending upon average wind speeds at the site). Nuclear power plants generate only about 16 times as much energy as they consume and coal plants generate just 11 times as much energy as they consume.

This is another strange question and answer. I guess it makes sense that a wind turbine creates a high multiple of the energy that it consumes, because the marginal cost of fuel (wind) is zero. The issue is that this power is variable in time (possibly off-peak) and in quantity.

In general, wind energy in Illinois makes sense because most of Illinois is damn ugly. It is flat with cornfields and not much to look at. Actually the area near Lena, IL where these turbines are located is probably one of the prettiest parts of Illinois (admittedly, not saying much). But I don't necessarily think that the wind farm is bad on the horizon, it is actually pretty cool. I don't think that the wind farms significantly impact the farm economy; they take up some amount of land but not a lot of total acreage.

The issue too is cost efficiency. $200M was spent for 100 MW of capacity, and this "capacity" is when the wind is blowing at a consistent rate best for the turbines. I don't know what the practical capacity of a wind farm is, it obviously depends on specific circumstances, such as how windy it is. We also would need to understand the useful lives of the gear; they had some trouble with blades made in India but likely they have this figured out in the most recent wind farms.

At least in Illinois we have a decent transmission corridor and it is located near some urban areas in Iowa. We probably will be seeing more of these wind farms in the future.
Cross posted at Chicago Boyz

2 comments:

Dan from Madison said...

For some reason I love looking at windmills. The Mendota Hills wind farm off of route 39 in north central Illinois is a pleasant thing to look at on a VERY lonely stretch of ugly highway. Here is the wiki:
http://en.wikipedia.org/wiki/Mendota_Hills_Wind_Farm

Dan from Madison said...

Hey, Youtube really does have everything:
http://www.youtube.com/watch?v=QBWJdsrzgas