Gusty winters, still summers stifle wind turbines’ appeal
This week, land use planners will consider changing the county’s codes to make it easier for people to install wind-powered electricity on their properties.
But installing a windmill on the Front Range doesn’t guarantee that the rotors will spin – or that they won’t spin too much.
The land use department has received more requests about wind turbines in the past few years, according to planner Greg Oxenfeld. Now, proposed wind turbines would have to clear the county’s review process, and even then, they are limited to the height constraints allowed by zoning.
“In the mountain district, there is a 30-foot height limit; in the agricultural zoning district in the plains, there is a 50-foot limit,” Oxenfeld said. “What I’m hearing is that, for an ideal situation, (the wind turbine) would have to be 30 feet above any of the other structures and trees in the area.”
Wind speeds increase with height, and houses and trees can cause wind to be turbulent and choppy on the lee side of obstructions, making higher turbines more desirable. But in the Boulder area, the problem can also be too much wind.
“As weather moves west to east over the mountains, it rolls down the front of the mountains really quickly,” said George Douglas, spokesman for the National Renewable Energy Laboratory. “As the wind pours over the mountains, it bounces around – it’snot very steady, it’s gusty. Above about 50 mph, the generator will burn out.”
Boulder’s brutal gales are most prominent in the winter, and summers tend to be still, Douglas said. Neither is a good formula for a wind-power resource.
Wind resources can be classified by wind power classes, with Class 1 having the least potential and Class 7 the most. The city of Boulder is in a Class 1 wind area, but there is potential for better wind in the mountains of western Boulder County.
Still, Douglas cautions that the quality of wind would be very site-specific.
Though no residential wind turbines have been built in the county, the county’s new green building program may spur new applications. Finalized earlier this year, BuildSmart would require larger houses to have some on-site renewable energy.
“With the new sustainability initiatives, we expect there will be more demand for these types of facilities,” Oxenfeld said. “And there is more availability of roof-top type facilities. There may be certain types of systems that will work better in Boulder County.”
By Laura Snider
25 March 2008
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