South Dakota State University
South Dakota Climate and Weather

SD Wind Resource Assessment Network (WRAN) Home Page

Last update: November 14, 2008

WRAN users: we want to hear from you. We are considering making some changes to the types of data posted on this site. Specifically, it seems that most users need only the monthly data files, so we are considering focusing our efforts on those instead of the graphical reports. If you are a user of WRAN data, we would like to hear from you as to how you use the data, and what would make it more useful to you. Please drop us a line at

To ask questions about this site, the WRAN, or the data, or to request raw data or alternate formats, please contact:
Dr. Dennis Todey
Agricultural Engineering
South Dakota State University
Brookings, SD 57007
Ph: (605) 688-5678

Table of Contents

Interpreting the data
There are some important facts to keep in mind when reading these data. These are noted in each site's Notes for Data Interpretation.

What is WRAN?

The WRAN is a network of eleven towers. These instrumented towers are measurement stations scattered South Dakota. The wind speed and direction is measured at each site using NRG systems meteorological equipment. NRG is a global leader in wind measurement technology. The WRAN stations are located near the towns of Leola, Crandall, Summit, Fort Thompson, Crow Lake, Gettysburg, Murdo, Medicine Butte Ridgeline, Belle Fourche, Faith and Martin. They are shown at their location on the map below. The green targets on the map mark the eleven WRAN sites. This data is being collected and interpolated, and updated weekly. The data is then averaged over the entire month at each site. Contact Dr. Dennis Todey for the monthly data archive.

Figure 1: Transmission Lines/Wind Speed 

The Wind Resource Assessment Networks 2001 sites are owned by South Dakota State. They are Ft. Thompson, Crow Lake, Crandall, Leola, and Summit. Each site is equipped with the following instruments:

The 2004, 2005, and 2006 sites are equipped with a different than the previous towers.

The 2007 sites are owned by South Dakota. They have been placed on Public Broadcasting Towers near the towns of Faith and Martin.

Data from the site will be collected by South Dakota State University's State (SDSU) State Climate Office (SCO) and will be made available to the public via this website.

What is the purpose of the WRAN?

There are several reasons why the WRAN was built. One of the most obvious is that it will allow statistical verification of the existing resource assessments of our state. South Dakota has tremendous potential as an exporter of wind-generated electricity. There has recently been a great deal of publicity over a Pacific Northwest National Laboratories study conducted in the early 1990s that ranked the contiguous 48 states in terms of their potential to produce wind power. (Click here for the results of this study as given by the American Wind Energy Association.) South Dakota ranked fourth in that study. Also, more recently, detailed maps of the wind resource in South Dakota were produced by the National Renewable Energy Laboratory (NREL). Unfortunately, both of these studies had to rely heavily on computer-generated models and very sparse measured data, because very little appropriate measured data exists. The WRAN will provide valuable data that we anticipate will validate the NREL maps, and perhaps suggest minor adjustments.

There are many other benefits the WRAN will provide. The data it will measure will be at heights above ground that are more appropriate for predicting the performance of large modern wind turbines, as opposed to data collected at National Weather Service stations whose anemometers are usually only about 9 m (30 feet) above ground. Also, we will collect some different types of data than most wind measurement networks, which will allow a series of important studies of the potential impact and value of South Dakota's wind power. (For more information on these studies or types of data, contact Dr. Dennis Todey. In addition, all of the WRAN data will be made available to the public via this internet site. This will hopefully enable extensive informed discussion among all South Dakotans on such important
topics as rural economic development and transmission system expansion.

Who is responsible for WRAN?

Wind Powering America: The WRAN was made possible by a grant from the Department of Energy through its Wind Powering America project, and by a grant from the South Dakota Governor's Office of Economic Development.

East River Electric Cooperative: The 2001 installation sites, communications network airtime, and installation assistance were generously donated by East River Electric Cooperative of Madison, SD.

West Central Electric Cooperative: The Murdo site is sponsored by West Central Electric Cooperative.

Gettysburg-Whitlock Bay Economic Development Corporation: Gettysburg site was installed and had been maintained by the Gettysburg-Whitlock Bay Economic Development Corporation. Unfortunately the WRAN project has not received data from the Gettysburg
tower since late last year.

Kennebec Telephone: An independent land owner, Warren Karlen and his brother Brad funded their own tower on Medicine Butte Ridgeline, which is north of Kennebec and Reliance, SD. They had a local company, Kennebec Telephone, install
the tower and instrumentation.

Black Hills Corporation: Another new site near Belle Fourche is being sponsored by the Black Hills Corporation. They have been extremely generous and an integral part of funding some of the WRAN. The Black Hills Corporation also installed and continues to maintain the Belle Fourche

Contact Information:

The head of the WRAN project is Dr. Dennis Todey of the Agricultural Engineering Department. For further information on this project, please contact him.

To the greatest extent possible (within the constraints of our use of existing towers and resources), we are conducting this wind assessment program in accordance with the guidelines laid out in the 1997 Wind Resource Assessment Handbook (National Renewable Energy Laboratories and AWS Scientific, Inc.).