As one of the fastest growing forms of renewable energy, wind turbines are sprouting up all over the country. On a recent airline flight across the country, I was blown away to see areas in northern Texas with rows of wind-turbines that went on for miles—some of which included well over of a hundred turbines. Now I know why they call them wind farms! This technology is increasingly popular in rural Alaska, where the cost of fuel to generate electricity is through the roof expensive. As with all good things, they come with potential impacts. As pilots, wind turbines provide several challenges: initially as obstructions we have to avoid during flight. If located too close to airports, they interfere with instrument approaches resulting in higher minimums and reduced access. Finally, when the wind blows they represent a source of turbulence, which we still have much to learn about (more on that later).
Interface to the Interactive Wind Farm Map, starts with an overview of where towers are found around the country.
Locating individual wind turbines
Recently the US Geological Survey has given us a new tool to locate wind turbines, on a nation-wide basis. A new interactive mapping application, provides access to a database that not only shows us where wind turbines are found, but records their height, blade length, and other information on a tower-by-tower basis. Prior to this, while some states captured the locations of individual wind turbines, there was no uniform database that provided this information across the country. Starting with the FAA’s Digital Obstruction File (through July 22, 2013), a USGS team led by Dr. Jay Diffendorfer located over 47,000 turbine sites, verifying individual tower locations with high-resolution satellite imagery. This data base gives us a much better way to find individual tower locations, with a location accuracy estimated to be within 10 meters.
While still few in number, wind turbines are sprouting up across Alaska.
A row of wind turbines just outside Unalalkeet, on the west coast of Alaska. According to the USGS interactive map, they have a total height of 156 ft. tall
This database is designed to support research into environmental effects on both critters that fly, and wildlife habitat. But these data may also be useful in the future to project the impact of down-wind effects on general aviation airports, which is still an evolving research topic. A recent study at the University of Kansas has shown that the turbulence from a wind turbine extends further as wind speed increases, up to 3 miles in some cases. This and the potential increase in cross winds could be a significant impact for small aircraft at GA airports. Hopefully, more work will be done to quantify these conditions, leading to improvements in the FAA’s obstruction review process, which today only takes into account the height of an obstruction above ground when air space reviews are conducted.
All maps are only as current as the date used to make them. This data set incorporated information from FAA’s obstruction file as of last July. And if you come across wind turbines that aren’t in the database, please capture what information you can and send an email with the location to [email protected].
Thanks to this effort, we have a better way to learn where wind turbines are located in the areas where we fly!