The Sherrard School District hired Ameresco to install a 600kW wind turbine for their middle and high school building that produces 692 volts.
As the turbine produces more power than the building needs in the summer months, the extra power will go on the grid as a credit to the school. In the winter months, the turbine will not produce enough power, which will require the school to get the rest from MidAmerican. Balancing out the extra in the summer and the shortage in the winter will provide Sherrard with a near zero balance.
Tri-City Electric Co. installed factory wiring in the turbine, which was then tied into the transmission lines at the school as well as MidAmerican Energy.
The turbine generates power beginning at 5 mph and uses its electrical breaking to stop at 55 mph. The meteorological equipment on the turbine tells where the wind is coming from and how fast it is going. This allows the turbine to change directions into the wind as well as change the pitch of the blades to generate the most power.
The blades are 71 feet long from the center and from the center of the turbine to the ground is 160 feet. The structure has a 28-foot deep foundation with 110 anchor bolts that are 28 feet long and 1 1/8 inches in diameter. The payback from the turbine should be gained within a 12- to 15-year period.