MGE built and operates a wind farm consisting of 17 turbines (each 660 kW) to provide renewable, Wisconsin-based electricity.

Annual Energy Production
23,000,000 kilowatt-hours annually—enough electricity for roughly 3,300 homes (assumes 98% availability and 23% capacity factor). The rated power output is 660 kW at 33 mph (optimal operating wind speed).

Wind
Average wind speed is 13 to 14 mph (at 110 feet aboveground). Wind blows predominantly from a west (from the northwest through the southwest) direction. The cut-in wind speed is 9 mph and the cut-out wind speed is 56 mph.

Towers
Each tower weighs 73.5 tons with a height of 213' and diameter of 12' at the base and 6.5' at the top. Tubular steel tower assembled in three sections with internal safety ladder and nacelle access. Towers are manufactured by Beaird Industries, Shreveport, LA.

Turbines
Each turbine weighs 20 tons (complete nacelle without rotor) and has an expected life of 30 years. They are Vestas V47-660 kW pitch-regulated wind turbines with OptiSlip and OptiTip. These are horizontal axis, up-wind turbines.

OptiSlip generator system allows rotor and generator to vary their revolutions per minute (RPM) by up to 10% during wind gusts. This minimizes wear and improves quality and supply of electricity produced.

OptiTip pitch-regulated system controls blades so they are always tilted to the optimal angle for wind conditions. Optimizes production and minimizes noise level.

Rotors
Three 77' blades (154' rotor diameter) constructed of fiberglass reinforced epoxy and other composite materials. They weigh 7 tons and spin at 28.5 RPMs.

Turbines and rotors are manufactured by Vestas Wind Systems A/S, Lem, Denmark.

Yaw Drive System
Electric motor driven with wind direction sensor and cable dewinding control. Braking accomplished through friction pads.

Gear Box
High-performance planetary/helical.

Generator
The nominal voltage is 690 VAC for the single-speed, variable slip, asynchronous, four-pole induction generator.

Foundation Design
Concrete pier 15' to 30' deep with 14' external diameter. Anchor bolts attach tower to the foundation.

Control System
Computer-controlled, automatic, independent operation and remote supervision from operations center in Madison. Microprocessor-based monitoring of yaw, hydraulic, ambient conditions, rotation, generator, pitch system, grid, power factor correction, thyristors (generator cut-in) and remote monitoring.

Integrated Lightning Protection
System consists of lightning receptor points, conductors, grounding system and surge protection for every subsystem.

Miscellaneous
The grid interconnection is 690-volt cables to 750-kilovolt ampere (kVA) step-up transformers to 24.9-kV collection voltage underground to overhead to 138-kV overhead transmission line.

The brake system consists of a primary and secondary brake. Primary: rotor-pitching mechanism (feathers blades); secondary: hydraulic disc brake.

The total cost of the project was $14.5 million. The noise level is 47 decibels at 800' downwind.