Print-friendly version

Looking back—and ahead—at utility wind projects

The 10 turbines of Platte River Power Authority’s Medicine Bow wind project have been supplying renewable energy to four municipalities since 1998. (Photo courtesy of Platte River Power Authority)

As wind turbines have sprouted across the hills and plains of Western’s service territory, the Energy Services Bulletin has followed our customers’ efforts to add this renewable resource to public power portfolios. Revisiting some of these projects shows how both the technology and the power industry have matured.

Lamar, Colo., Light and Power and Lenox, Iowa, Municipal Utilities are still relative rookies with about a year of operation. The municipalities launched development on a modest scale – four turbines in Lamar and a single 750-kW unit in Lenox.

NMPP Energy’s Kimball wind project has two years' experience and a larger operation that generates 10.5 MW with seven turbines.

Wind power veterans Platte River Power Authority in Ft. Collins, Colo., and Moorhead, Minn., Public Service have been generating clean energy since 1998 and 1999 respectively. Platte River’s Medicine Bow wind project boasts 10 turbines supplying the municipal utilities of Fort Collins, Loveland, Longmont and Estes Park, Colo. Moorhead’s “Capture The Wind” program markets electricity from two turbines to town residents.

Utilities adjust to variable resource
Size doesn’t matter to the wind, however — it blows when it blows. Each developer reported that initial generation estimates seldom matched the actual output. Once they adjusted to the resource’s variability, the utilities were generally pleased with their units’ performance.

Lamar Electricity Superintendent Rick Rigel noted only a slight difference between the 35.65 percent capacity factor the feasibility study projected, vs. the turbines’ 32.48 percent performance. “One of our units has a more than 95 percent availability rate, and even with start-up problems, the other two do better than 90 percent,” he said. “We have every reason to believe we will attain the estimated generation.”

Kimball experienced a similar shortfall of about three percent, and is also expected to improve. “Our availability has been steadily increasing,” said NMPP Energy Communications Manager Bob Selzer. “We anticipate next year with normal winds and normal availability to be close to our initial projections.”

Moorhead Energy Services Coordinator Kevin Bengtson recalled that the utility’s estimates were between 1.4 million and 2.2 million kWh per year. The actual output averaged 1.5 million kWh annually from each turbine.

Engineers predicted the Lenox turbine would generate about 10 percent of the town’s native load. “It actually produced up to 12 percent in the winter,” said General Manager Dave Ferris. “The summer months were shy of the 10 percent figure, though.”

He pointed out that the town’s load is almost as variable as the wind. It has experienced both winter and summer peaks, making forecasting difficult.

Like Lenox, Medicine Bow generates most of its electricity in the winter. “That’s about 70 percent of its production,” said Platte River Customer Services Engineer Paul Warila. “That makes it convenient to conduct maintenance in the summer.”

The net bottom line on Medicine Bow’s average production is only one percent off from study estimates.

Straightforward marketing options
Forecasting generation may be a complicated business, but the marketing options are simple: sell the electricity directly to the customer or sell the attributes—green tags—in the renewable energy marketplace.

Lenox, Moorhead, Kimball and Medicine Bow have taken the direct sales route. According to the National Renewable Energy Laboratory’s 2003 green pricing program rating, Lenox had the highest customer participation in the nation; Moorhead was third highest.

NMPP members prefer to take credit for Kimball’s renewable energy, rather than market the attributes, and Platte River had to expand Medicine Bow in three phases to meet customer demand. “We’ve got the market for the energy, so we don’t need to sell green tags,” said Warila. “If we sold green tags, then the cities couldn’t count their power as green. That would be double counting,” he pointed out.

Lamar Light and Power takes a mixed approach, adding some wind energy to the city’s power mix and selling some green tags. “We’ve participated in a few requests for proposals for additional sales,” said Rigel. “We are finding the market very competitive and the value of the green tags much less than anticipated.”

The municipality is working with its power supplier Arkansas River Power Authority and a Boulder, Colo., consultant to explore further green power marketing opportunities.

Several factors affect expansion plans
Looking to the future, Platte River and Moorhead Public Services express the confidence that comes with experience, but in different ways.

Moorhead has room on its present wind site for another turbine, and is working with interested customers to develop an additional wind turbine. However, the expiration of the Minnesota REPI and Federal REPI incentives make it difficult to justify the additional cost of the wind turbines. “Renewable energy already makes up more than half of our generation, so we are exceeding the state goal,” said Bengston.

He added that Missouri River Energy Services, the utility’s power wholesaler, can apply the town’s wind generation toward meeting state standards.

A new turbine will be added at Medicine Bow early this year, a 2.5-MW unit designed by Clipper Wind Power. “It has four generators on board, variable speed and rotors 93 meters long,” Warila said, “and it’s really great looking.”

Platte River signed an agreement to purchase all the power from the C93 commercial prototype for one of its members, the city of Ft. Collins, Colo.

Lamar and Kimball express cautious optimism but have no current plans for expansion. “We don’t have the load to support additional wind generation right now,” said Rigel.

Transmission limitations and uncertain ancillary service rates are keeping MEAN’s ambitions in check for the time being. “Project expansion represents an unacceptable cost risk at this point,” said Selzer.

Success is a powerful incentive to do more. Encouraged by recognition from the Department of Energy and the Environmental Protection Agency, Lenox is eyeing other potential wind sites. The city owns 10 acres with good wind resources that could support another turbine, and farmland on a windy ridge near town could hold five more. “There’s talk in the boardroom about opening up the area,” said Ferris, “but so far, it’s just talk.”

There is also talk of putting together a group of Iowa towns with wind turbines to market green tags, he added. “We’re working with Wall Lake, Waverly and Algona, and Stewart may be joining the project.”

Such collaborations point to more development and to a growing pool of experience for the industry to draw on. Energy Services Bulletin looks forward to looking back on that progress.