Minnesota Power has finalized the purchase of a 465-mile transmission line stretching from North Dakota to Hermantown.

For approximately $70m, the utility has acquired the 250kV line connecting Center, North Dakota. with its Arrowhead Substation in Hermantown, Minnesota. Purchase of the direct current (DC) transmission line from the Square Butte Electric Cooperative is expected to further Minnesota Power’s plan to bring renewable energy into its system.

Minnesota Power plans to develop several hundred megawatts of new wind generation in North Dakota and deliver wind-fueled electricity to customers via the DC line. The company is already laying the groundwork for construction of its Bison wind farm, a 75MW installation near New Salem, North Dakota. The project, consisting of 33 turbines with a 2.3MW capacity each, will be installed in two phases. Phase one, which will involve the construction of the first 16 turbines, is scheduled to be operational by the end of 2010.

In November, the Federal Energy Regulatory Commission issued written orders authorizing Minnesota Power’s acquisition of the transmission facilities. On December 21, the Minnesota Public Utilities Commission issued its written order approving Minnesota Power’s purchase of the DC line.

Eric Norberg, senior vice president of strategy and planning at Minnesota Power, said: “The transmission of renewable energy has been a big challenge for our industry. With the closing of this strategic agreement, we’re proud to be at the forefront of long distance wind energy transport.”

When Square Butte built the DC line in the 1970s, it was designed to move electricity from the coal-fired Young Station to supply Minnesota Power’s taconite customers in northeast Minnesota’s Iron Range.

Minnesota Power intends to use its DC line as a method of moving ‘wind by wire’. Electricity generated at the Young Station is now shared by Minnesota Power and Minnkota Power Cooperative, an affiliate of Square Butte. Over the next several years, Minnesota Power will phase out its generation rights at the Young Station, allowing Minnkota to eventually take all of the coal-based electricity it once shared, Minnesota Power said.