Most of North Dakota’s wind turbines have barely begun operating, but state regulators have started drafting rules that would apply if the massive towers quit producing electricity.
‘‘My hope is that we never need to use these decommissioning rules,’’ said Susan Wefald, the president of the state Public Service Commission. ‘‘However, if something changes in the industry so that these turbines are no longer needed, I want to have something in place that would take care of them.’’
The proposed rules, scheduled to get a public hearing Nov. 29, may require wind farm operators to post bonds to cover decommissioning costs once the facilities have been operating for at least 10 years. Wefald said wind farms usually have a useful life of 15 years to 20 years.
Tearing down a defunct wind farm would include dismantling its towers, which are more than 200 feet tall, as well as removing transformers, underground cables and the concrete footings that provide a foundation for wind towers.
North Dakota’s proposed rules say the property that hosted a wind turbine site would have to be restored to ‘‘substantially the same physical condition’’ as existed when the site was built.
‘‘To the extent possible, the site must be restored and reclaimed to the topography and topsoil quality that existed just prior to the beginning … of construction,’’ they say.
A wind turbine would be targeted for decommissioning if it had not produced electricity for at least one year, the proposed rules say. Removing a wind tower and its associated equipment would have to be done within 18 months after it reached the end of its use.
The rules are similar to provisions the Minnesota Public Utilities Commission has included in wind farm site permits, which require companies to submit restoration plans for turbine locations before they are built.
Once the permit expires or a wind turbine no longer operates, the site must be reclaimed within 18 months, the Minnesota permit language says.
North Dakota has about 178 megawatts of installed wind energy capacity, most of which has been installed in the west-central and southeastern parts of the state within the last four years. Its largest single wind farm, a 159-megawatt development near Langdon in northeastern North Dakota, is nearing completion.
Analysts say the decommissioning of wind farms has not been an urgent subject in most states because of the relative newness of most U.S. wind development.
One exception is California, where about 1,300 megawatts of the state’s 2,230 megawatts were installed in the 1980s. The California Energy Commission, in a recent report, called the turbines ‘‘aging, outdated and inefficient,’’ but said it is often more profitable to continue operating them than to replace them.
The aging turbines are in some of California’s best wind resource areas, and repowering can increase the efficient use of them, the report said. ‘‘However, because of the structure of current contracts, as well as provisions in the (federal tax) code, these facilities have little economic incentive to repower,’’ it said.
In Europe, where wind turbines at least two decades old are more common, Denmark and Germany have extended incentives to encourage the replacement of aging turbines, according to the European Wind Energy Association.
North Dakota’s proposed rules give companies the option of submitting a schedule to return obsolete wind turbines to service rather than tearing them down, Wefald said.
‘‘Who would have guessed, 20 years ago, the size of the wind turbines that are being put up today?’’ Wefald said. ‘‘They may decide to terminate the use of the smaller ones, and just go to bigger ones that they find are much more efficient.’’
By Dale Wetzel
5 November 2007
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