WILLMAR -- Five electric utilities proposing the Big Stone II power plant in South Dakota will have a chance Wednesday to question independent experts hired by the Minnesota Public Utilities Commission who concluded the utilities underestimated power plant construct costs and overestimated alternative energy costs.
Otter Tail Power Company of Fergus Falls, the lead Big Stone II partner, and four other utilities will cross examine analysts from Boston Pacific of Washington, D.C. and call their own experts to testify at hearings beginning Wednesday in St. Paul in front of administrative law judges assigned to the Big Stone case.
The coal-fired power plant would be built in South Dakota, but the utilities need the PUC's permission to run the power lines into Minnesota. Energy and environmental groups are fighting the proposed power plant.
The PUC voted in June to continue its inquiry into the Big Stone II proposal to build transmission lines designed to deliver power from the plant near Milbank, S.D., to the Twin Cities and other cities in Minnesota, including Willmar.
The PUC deferred the decision on the certificate of need and route permits for the transmission lines and required additional proceedings to obtain independent, supplemental expert opinion and information concerning various cost factors affecting the proposed power lines, including the plant.
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The Willmar Municipal Utilities wants to buy 30 megawatts of power from the 500-megawatt plant.
Bruce Gomm, general manager of Willmar Municipal Utilities, said the partners have analyzed the Boston Pacific report. The report looked at construction costs, the cost of electrical generation using natural gas, and the effect of carbon taxes on cost.
Boston Pacific initially said the Big Stone partners used a construction cost that was too low because the partners looked at different years. But when the costs were normalized for inflation, the cost estimated by the analysts and the Big Stone group were "almost exactly the same,'' Gomm said.
On the cost of using natural gas, the Big Stone partners and Boston Pa-cific reported different numbers.
"But when they looked at the different parameters, they also realized that they were pretty close,'' he said.
The biggest discrepancy occurred in determining the effect of the cost of possible carbon taxes. The Big Stone partners capped their cost at $30 per ton, whereas Boston Pacific estimated a cost as high as $60 per ton, said Gomm in a report to the Municipal Utilities Commission on Monday.
In other business, Gomm reported on his attendance at the 44th annual Minnesota Power Systems Conference Nov. 4-6 at the University of Minnesota in St. Paul. Wes Hompe, utilities staff electrical engineer, also attended.
The conference keeps electric utility engineers and consultants informed about challenges facing the electrical industry and the latest available technology.
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The network of interconnecting transmission lines, also called the grid, will make greater use of "smart'' devices that will solve power line problems and take corrective action in a matter of seconds compared with minutes by humans. The purpose is to improve industry reliability, Gomm said.
"There is technology now where you can put more intelligent protection devices, relays and breakers that can actually see what's going on and know what the options are, can open and close switches to solve the problem all in a matter of seconds or less,'' he said.
Gomm said Willmar has already implemented some of those features into the city's substation protection devices. Another promising innovation is development of large batteries to store energy and help utilities smooth out times of expensive peak usage.
Batteries would be particularly advantageous for storing power generated by wind turbines during off-peak times, according to Gomm. He said a 2-megawatt battery installed in southwest Minnesota can store enough power to serve about 1,000 homes.
