The Real "Footprint"
This is one more in a series of pieces I am writing to try to examine non-nuclear technologies under the same microscope usually reserved for nuclear technologies.
I have been puzzled in the past about conflicting claims regarding the "footprint" of wind farms. A recent report and some very astute analyses by some colleagues of mine has opened my eyes. For wind farms, it seems, things are not as they first appear.
The argument made by wind advocates is that wind farms take hardly any land at all. They can be sited in the middle of farmland, and their only footprint is the small base of each tower. Crops or livestock can surround them. That certainly seemed plausible, so I have not fully understood the criticisms that the footprint of a wind farm was really much larger than the area occupied by the towers.
Let me hasten to point out that this post will address only wind farms sited on farmland. It will not address the special environmental and scenic implications of wind turbines on mountain ridges, and it will not address implications of offshore windmills. These have their own issues. I cover here only the "real" land use implications of windmills on farmland.
The report provides some numerical data on the real land use of wind farms. However, it errs in its comparisons to nuclear power, because, as a colleague has pointed out, they fail to factor in the megawatts per unit acre generated by a nuclear power plant compared to that from a windmill. Adjusting for the generation per acre makes nuclear much more land efficient--up to about a factor of 10 or more, depending on which end of the stated range you use for each. (The observation is from Margaret Harding in a communication and to my knowledge is not available on a website.)
She and others have noted other farm-related implications of windmills on farmland:
• The land requirements for rights of way to access the wind turbines.
• The added difficulty of operating large tractors and combines around the bases of turbines (probably resulting in an effective loss of the land immediately surrounding the towers).
• The sensitivity of livestock to the noise and light from wind turbines.
(There are anecdotal reports of reductions in milk production by cows.)
• The difficulty and danger of crop dusting, which is causing crop dusters in some areas to refuse to work around windmills. The net result is either application of pesticides by less efficient (and more petroleum-intensive) methods, or reduced crop production per acre.
Some of these reports are anecdotal, so clearly, this is another case where we need more facts. I doubt that these factors would rule out the use of wind farms on agricultural land. However, the ultimate findings could affect how much we can really expect such wind farms to penetrate the nation's farmland, where they can be sited with least impact, and what side effects we would have to tolerate, and perhaps, how to minimize them.