David Montgomery

PIERRE — A long-awaited study conducted by the Western Area Power Administration is cautiously optimistic about the potential for wind turbines along the Missouri River to reduce WAPA’s costs in expensive drought years.

The Wind and Hydropower Feasibility Study, released in draft form Monday, was mandated by the Energy Policy Act of 2005. Its goal was to determine whether wind power — which requires no fuel and produces no pollution but which does not produce a constant level of electricity — would be a good complement for WAPA’s existing hydropower facilities such as the Oahe Dam.

Capital Journal Image A new study completed by the Western Area Power Administration shows mixed results from a proposal to build wind turbines along the Missouri River. When water levels on the Missouri are low and WAPA has to buy power on the market, the wind turbines are a cheaper alternative and save WAPA millions of dollars per year. When water levels are high, however, buying power from the turbines would cost WAPA more money than it would save. Dollar values on the chart are in thousands of dollars. Advertisement

“It turns out to be a fairly complicated process,” said Randy Wilkerson, a WAPA spokesman. “You’re trying to mesh two variables together. You’ve got a wind resource that’s highly variable over time, and you’ve got this hydropower resource that varies between high-water years and low-water years. In high-water years there’s excess electricity to sell, and in low-water years we have to go on the market to purchase that power.”

WAPA provides a significant portion of electricity used by local residents.

With the upper Great Plains region in a drought for almost a decade, WAPA has been forced to buy a great deal of power on the market, Wilkerson said. Since open market power is substantially more expensive than power WAPA generates itself, this has led to WAPA accumulating substantial debt and raising its prices for consumers — which in turn has led to higher utility costs for residents of Pierre and Fort Piere.

The study concluded wind power would have benefits, but only to a certain degree.

“One of the things we saw from the study is that in years of low generation, these wind projects make a lot of sense economically,” Wilkerson said. “When there’s plenty of water, economically the wind projects aren’t as viable. It’s kind of a project of balancing that over time to see where the economic breakpoint is.”

The optimal amount of wind power, according to the study, is 300 megawatts — about 200 wind turbines, or an 11 percent increase in WAPA’s total capacity.

The study found expanding wind power production along the Missouri River would have moderate benefits during drought years, saving WAPA almost $4 million per year. During years with normal water, the benefits decrease. When water levels are high and WAPA’s power purchases on the open market drop off to almost nothing, purchasing power from wind turbines would actually cost WAPA more.

Mike Radecki, the project manager for the wind-hydro integration study, said more wind power than 300 megawatts is less viable because of the time of day when strong winds tend to blow in Central South Dakota.

“A lot of the wind blows during the evening hours and into the nighttime,” Radecki said. “In that same time frame, our load is backing down into the off-peak load. Having more wind during that period isn’t as beneficial as if it were blowing during the day, during our peak load, which is when energy is more expensive.”

Republican Sen. John Thune has been a supporter of the idea of expanded wind power.

He said he welcomed the completion of the study.

“The conclusions weren’t as clear as they would have liked, but the clear conclusion coming out of this is that there are some models where a wind-hydro integration model makes a lot of sense,” Thune said.

Thune said he supports providing federal incentives to encourage the development of wind power.

Radecki said the report’s recommendations were made under a mandate to avoid transferring any added cost to consumers.

“We don’t want our rate-payers to pay for a project that isn’t economical,” Radecki said. And if the project is economical, consumers could see cheaper electricity.

“The benefit would be, depending on our hydro conditions, energy at a cheaper rate than we could pay for on the market,” he said.