The building permit for the Bent Tree Wind Farm shows a valuation of $17 million.

The Freeborn County Planning and Zoning Office issued the permit Friday to Wisconsin Power & Light for 122 wind-turbine towers.

It was the final permit needed in the process. Now the Madison-based company need only build the structures.

Full construction likely will start in the spring but initial steps could be taken starting this fall.

The valuation is on-site construction. It reflects the estimated cost of building foundations for the towers. It does not include the cost of the towers and turbines themselves. They are considered mechanical equipment.

A valuation normally is factored to determine building fees. However, the county charged WP&L a set amount of $56,320 to cover the permit fee and plan-review fee.

The building-permit application was dated Aug. 18.

The wind farm is designed to generate 200 megawatts of electricity. The valuation came to $17,080,000.

This also is merely the initial portion. WP&L intends to build other structures, too, and there are plans to expand the wind farm to 400 megawatts.

During September the Freeborn County Planing and Zoning Office had issued 38 building permits with a listed valuation of $701,635. Now, with the addition of the Bent Tree project permit, the total estimated valuation for building permits issued by the county for the year increases to $21,148,361.

The Freeborn County commissioners on Oct. 20 approved a conditional-use permit for a transmission line to connect the wind farm to the Hayward substation. The Minnesota Public Utility Commission on Oct. 1 approved a site permit and certificate of need for the wind farm itself.

WP&L plans to build the Bent Tree on 32,500 acres near Manchester and Hartland townships.

The Wisconsin Public Service Commission approved the project on July 10. The panel has jurisdiction because the rate increases would affect Wisconsin consumers. Minnesota has a greater potential for wind energy than Wisconsin. WP&L will use the Bent Tree Wind Farm to help meet renewal-energy requirements of that state.

The project is expected to cost nearly $500 million. WP&L plans to recover some of the cost through $91.7 million in electric and natural-gas rate increases next year.