South Dakota State University
Wind Resource Assessment Network (W.R.A.N.)
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 firstname.lastname@example.org. Thanks.
To ask questions about this site, the WRAN, or the data, or to request raw data
or alternate formats, please contact:
Dr. Michael Ropp
Brookings, SD 57007-2220
Phone: (605) 688-5266
Table of Contents
Data: Summary data from all sites
Medicine Butte Ridgeline
What is the WRAN?
What is the purpose of the
Who is responsible for the
Wind turbines at work: photos and short movies of wind
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 the WRAN?
The WRAN is a network of
eleven towers. These instrumented towers are measurement stations scattered
across 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
The WRAN stations are located near the towns of Leola, Crandall,
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. Michael Ropp for the monthly
Figure 1 Transmission Lines/Wind Speed
using a browser other than
Internet Explorer please click on map.
Resource Assessment Networks 2001 sites are owned by South Dakota State.
They are Ft. Thompson,
Crandall, Leola, and Summit.
Each site is equipped with the following instruments:
Anemometers, 2 at each elevation of 50-meters and 70-meters above ground.
Wind Direction Vanes, 1 at each height.
Pyranometer (solar irradiance measurement device) at ground level, mounted
Datalogger to record measurements at regular ten minute intervals
The 2004, 2005, and 2006 sites are equipped a different than the
Gettysburgís WRAN tower is owned locally by Gettysburgís Economy and Development
Co-Op. It meets the WRAN standards because it uses the same meteorological
equipment. It has 2 Anemometers and 1 Vane at 50-meters as well as a
temperature sensor near ground level. Gettysburg
does not have wind measuring sensors at the 70-meter or 90-meter elevations. It
also does not use a Pyranometer to measure solar irradiance.
includes the equipment from the above 2001 WRAN sites. In addition to earlier
WRAN towers, Murdo is also equipped with 2 anemometers and 1 vane at 90-meters.
Butte Ridgeline and Belle Fourche sites are
both privately owned. They are instrumented the same as the Gettysburg site.
The 2007 sites are owned by South Dakota. They have been placed on Public Broadcasting
Towers near the towns of
Faith and Martin.
towers measure wind speed and direction at 50, 70, and 90 meters height.
Anemometers and 1 Vane have been placed at each level.
Pyranometer, 1 Temperature Sensor, and 1 Datalogger will be placed near ground
Data from the site will be collected at South Dakota State University (SDSU) 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
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. Ropp.) 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.
responsible for the 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.
Electric Cooperative: The
Murdo site is sponsored by West Central Electric Cooperative.
Bay Economic Development Corporation: The 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.
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.
new site near Belle Fourche,
SD 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 Tower.
The head of the WRAN
project is Dr.
of the SDSU Electrical 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
Renewable Energy Laboratories and AWS Scientific, Inc.).
Last update: August 22, 2007