After two years of feasibility studies, the prospect of large wind turbines on the Cirque near the top of the Snowmass Ski Area has run into too much turbulence.
“What you have at this site is a swirling vortex – the wind comes over that cliff and swirls like a mini-cyclone funneled towards the met,” wrote Robi Robichaud, a researcher at the National Renewable Energy Lab, in an analysis of the wind data.
A “met” is a meteorological tower. In this case, a 160-foot-tall needle of a tower put up in the fall of 2008 about a third of the way up the western edge of the treeless Cirque at over 11,000 feet.
The data from the first winter indicated the Cirque had consistent and strong winds. And last spring, Jim Stark, the winter sports ranger for the U.S. Forest Service of the Aspen-Sopris Ranger District, was optimistic about the possibility of installing three wind turbines with 35-foot-long blades at the ski area, which is on Forest Service land.
The turbines could have produced enough electricity to meet 60 percent of Aspen Skiing Co.’s company-wide demand.
But the “swirling vortex” means the Cirque is a no-go.
“A turbine in the Cirque in those locations is pretty much out,” Stark said. “It just can’t react fast enough to changes in wind direction. It just stops and waits to power up on a cleaner flow of wind.”
Most skiers and riders who ride the Cirque lift, or the Big Burn lift, can vouch for the windswept nature of the upper slopes of Mount Baldy. But it is not the big gusty wind events that make the site too turbulent for turbines.
“The worst TI (turbulence intensity) is at relatively low wind speeds – so swirling is going on,” Robichaud wrote. “At higher wind speeds, the air molecules keep pushing each other forward, no time for swirling.”
Robichaud also found that the “air density” on the Cirque is low. And that, combined with the high altitude, means that “the wind power class is lower than I might have expected.”
“This means you have ‘less leeway’ in accepting other factors less than ideal as you will not be generating as much kWh (kilowatt hours) as one might have expected,” Robichaud wrote.
Stark has been working on the project in an effort to help the Forest Service meet a federal mandate for the agency to reduce its greenhouse gas emissions by 30 percent by 2015.
“I hate to accept defeat,” Stark said. “I still think it is the right thing to do at the right time, but it is hard to find the right place.”
Stark said at least two good things have come out of the effort. He received a grant from the U.S. Department of Energy to write a guidebook on installing turbines at ski areas and the Aspen-Sopris District received a Forest Service grant to create guidelines for installing turbines on Forest Service land in general.
Stark’s partners in the Cirque effort were Aspen Skiing Co.’s Vice President of Sustainability Auden Schendler and Jeremy Celayeta, a sales representative at Leitner-Poma, a chairlift manufacturer in Grand Junction with an Italian division called Leitwind that makes turbines.
If the wind data on the Cirque had been optimum, SkiCo, the Forest Service and Leitner-Poma were prepared to move forward to install three $4 million wind turbines.
Instead, SkiCo invested $20,000, split the cost of the met tower with Leitwind, and helped them set it up. However, Schendler said Leitwind put in a lot more money as the first wind-measuring tower broke and they did extensive analysis.
“They were a generous partner in the project,” Schendler said.
The SkiCo is now looking to connect with a wind farm somewhere else that needs a long-term power-purchase agreement to get up and spinning.
“It just shows how difficult it is to do new power development,” Schendler said, listing challenges like finding a site close to power lines, getting a utility to buy in, monitoring the wind on the site for one or two years, getting permits and finding turbines to buy.
“If you were a rock star, you might have a wind farm up in five years,” Schendler said. “It is frustrating to someone who wants to get something done.”
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