Broyhill Wind

I have learned a lot about wind energy while studying in the Technology Department at Appalachian State University. Besides being a member of the Appalachian State University Renewable Energy Initiative, I am working for the Appalachian Institute for Renewable Energy (AIRE) to install a community scale wind turbine in Western North Carolina. Therefore it is also natural that I am involved in this project. I provide technical support to the project manager, currently Crystal Star, with help from Jonathan Pierson, Gernon Harvey, and Bryan Johnson.

Resource assessments are valuable for selecting or screening an area for suitability. Below are some of my contributions to the project using ArcGIS and data high resolution (200m) wind data from AWS Truewind. (This data is was purchased by the state and is available to the public; contact or visit

The following is shows the 50m (164ft) annual average wind speed for Appalachian State University (ASU) and Boone, NC.

annual average wind speed at 50m

The following shows the 50m average power density for ASU and Boone.

average wind power density at 50m

Further analysis of the computer modeled data shows the estimated output for different wind turbines. These can be seen in the following documents: main distribution data & estimated output.

Because the Mountain Ridge Protection Act (commonly known as the Ridge Law) is an important legal and political consideration to the placement of wind turbines in Western North Carolina, it is good to know if the potential site for the REI's wind turbine is considered a protected ridge. The ridge law prohibits constructing anything over 40ft tall on a protected ridge. It was written in reaction to the 1982 construction of Sugar Top Condominium. It is a square 10 story building on the top of at 5,000 mountain; it is unaffectionatly known by some as Sugar Cube. It touts its extraordinary views, but is seen by everyone else as an eyesore.

Although there is an exemption for "windmills" in the Ridge Law, the state's attorney general misrepresents this a traditional water pumping windmills common to the midwestern states. However from 1979 to 1983 NASA and DOE operated the experimental MOD-1 (2MW) windmill on Howard's Knob in Boone. Although there were some complaints about the MOD-1, it was nothing in comparison to the oppostion toward Sugar Top. In fact quite the oppostite was thought about the MOD-1. In Natasha Tompson's 2003 essay, she states: "According to a 1982 survey conducted by Appalachian State University students in a business class, 73% of Watauga residents felt that the Mod-1 boosted tourism to Boone.  While no statistics exist to support this belief, it does indicate that Watauga residents held the windmill in a positive light."

Read Louis Zeller's statement on the Ridge Law and wind power, published by the Blue Ridge Environmental Defense League --"The NC Ridge Law Is No Obstacle to Wind Power".

For the Broyhill site, the following picture shows contour lines at 3,600ft in red, and 3,100ft in green. The Red line is approximately the highest point on the ridge where the site is located. Because this is above 3,000ft it is potentially a protected ridge. However because the adjoining valley is not below 3,100ft (and therefore less than 500ft below the ridge top), this is not a protected ridge and therefore the ridge law does not apply. The beige contour shows the height of the Broyhill site the REI proposes to build a wind turbine.

Contours & Ridge Law

Another very important aspect is the visibility of the wind turbine. The REI would like it to be very visible, making the statement that ASU and the students who voted 93% in favor of the REI in March 2007 support renewable energy. On the other hand potential opponents and people who remember the MOD-1 on Howard's Knob in the early 1980s may not want something so visible. It is important for both to know from where the REI wind turbine could be seen. The first thing that needs to be known is what size the REI is considering. The REI currently has about $150,000 to put toward the project, but there is hope to get another $50,000. This amount would purchase a 100kW machine, which will have rotor diameter of about 20m (66ft) and hopefully a hub height of at least 30m (98ft) to get above the trees and the turbulence they create; 50m (164ft) hub height would be better. See the following picture for a guide to wind turbine sizes.

Turbine heights

The following .MOV animations shows a wind turbine that has a total height of 45m total height. This is representative of a 100kW, 20m diameter machine on a 35m tower. The trees are 60ft tall. The Broyhill Inn & Conference Center is 40ft tall. The water tank next to the wind turbine is 25ft tall. All other building are extruded to 30ft tall regardless of their actual height. You can use the QuickTime play head to scrub forward and backward to better understand the wind turbine and its relationship to the Broyhill Inn & Conference Center.

Fly around Broyhill wind turbine (.MOV) 40sec long, 3.7MB

Drive US321 and River St, ending at Watauga Library 60sec long, 6.7MB

Broyhill Movie Still River St Movie Stillframe

The following pictures show the view shed for the proposed REI wind turbine at Broyhill. The first picture shows from where a 50m (164ft) tower would be visible; the grayed-out areas will not see the tower. The second picture shows from where a 70m (230ft) total height would be visible. These do not take into account ground cover (trees), only the elevation of the land, so it is certain that the area where the turbines will be visible is smaller than that shown here.

50m view shed:

50m viewshed from Broyhill

70m view shed:

70m viewshed from Broyhill

here are other links of interest to REI members: estimated Broyhill energy output (.PDF), Broyhill main distribution data (.RTF), & GIS-wind output spreadsheet (.XLS)

4 March Presentation (.PPT), 3.5MB


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Last update: 6 March, 2008