About WRAN

► home

The WRAN is a network of 11 instrument stations positioned throughout South Dakota. The stations are located near the towns of Belle Fourche, Faith, Martin, Murdo, Fort Thompson, Leola, Crow Lake, Crandall, and Summit and an area known as Medicine Butte in Lyman County. Working sites are indicated in red on the map below. Future sites near Buffalo, Lowry, Parkston, Tyndall and Howard are indicated in blue.

Red = working sites Blue = proposed sites
Data Collection Equipment

Each WRAN site includes a data logger to record measurements at regular intervals. Additional equipment is specified below.

The sites at Fort Thompson, Leola, Crow Lake, Crandall and Summit, which began collecting data in 2001, are each equipped with:

four anemometers, two each at 50 meters and 70 meters

two wind direction vanes, one at 50 meters and one at 70 meters

a temperature sensor at 2.5 meters on the tower leg

a pyranometer (solar irradiance measuring instrument) mounted horizontally at ground level

The site at Gettysburg came online in 2004, but was inoperable from January 2006 to April 2007 due to weather damage. It is equipped with:

an anemometer at 50 meters

a wind direction vane at 50 meters

a temperature sensor at 2.5 meters on the tower leg

The site at Murdo began collecting data in 2005. Sites at Faith and Martin began collecting data in 2007. Equipment at these three locations includes:

six anemometers, two each at 50 meters, 70 meters and 90 meters

three wind direction vanes, one at 50 meters, 70 meters and 90 meters

a temperature sensor at ground level

a pyranometer (solar irradiance measuring instrument) mounted horizontally at ground level

a photovoltaic panel (solar panel) at ground level

Data collection at Belle Fourche and Medicine Butte began in 2006. The sites are equipped with:

two anemometers at 50 meters

a wind direction vane at 50 meters

a temperature sensor at ground level

Data is collected and interpreted by South Dakota State University.

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 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 windpower. (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 windpower. (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 WWWeb site. This will hopefully enable extensive informed discussion among all South Dakotans on such important topics as rural economic development and transmission system expansion.