In what seems to be an unprecedented use of wind power, 15 small turbines are being used by an electric co-operative in the US state of South Dakota to prevent costly damage caused by ice build up when floodwater freezes around its transmission towers. If the wind turbines prove successful this winter, say utility co-operative officials, it would be a solution to the problem at a fraction of the cost of other ways of keeping ice away from the pylons.
The wind turbines are to power "aerators" that prevent water around the towers from freezing. The entire Dakotas region, as well as parts of Minnesota, have been hit by disastrous flooding in recent weeks and water depths around pylons can vary from 80 to 120 feet. If this water freezes, it buckles the metal towers. During the last three years, 15 of the co-operative's $40,000 towers, in an area of north central and north east South Dakota, have ended up standing in several feet of water in a marsh-like area.
Basin Electric Power Cooperative of Bismarck, North Dakota, which is part of a system that serves 1.5 million people in eight states in the upper midwest, has installed Windseeker 503 turbines on some of the towers on its 345 kV transmission line in South Dakota. The turbines are made by Southwest Windpower of Flagstaff, Arizona.
The concern about ice has been exacerbated by recent weather in the region. Blizzards in early April dumped several feet of snow after spring-like days with quite high temperatures. Disaster declarations were issued for South and North Dakota and part of Minnesota last month. At least eight people were killed, expected damage will cost upwards of $100 million, and power has been knocked out to thousands of customers.
The 60 watt wind turbines, installed about ten feet above the water line, can help prevent ice damage. Indeed other solutions, such as building "islands" around the towers or driving in protective sheet piling, can cost as much as $150,000 a time. In contrast, the wind turbines cost $6,000 each. It is still too early, however, to know if the programme is effective, says Stan Stelter of Basin Electric, because this winter has been unusually long. Another 17 inches of new snow, for example, fell in the area at the end of the first week of April.