A blustery wind swept through the Midwest farmland, spinning the blades on a school district’s wind turbine. Out of balance because of a broken part on a blade tip, the turbine began to vibrate, wobble and shake. The blades turned faster, until the support tower’s legs snapped off and vaulted the heavy turbine into the ground.

THE COST OF GOING "GREEN"
On the way down, the fiberglass blades struck electrical lines, breaking into pieces and knocking out power to the school. The small turbine saved the school about $3,500 a year in energy costs; the breakdown claim paid by HSB totaled $116,236.

NEW EQUIPMENT, NEW RISKS
We’re discovering on-site power generation where it has never been before, such as districts, office buildings and retail locations. New renewable forms of power generation, including wind, water and micro-turbines, are gaining acceptance.

CATCH THE WIND
Located near some of the world’s largest wind farms, the rural school district installed the 50 kW wind turbine to reduce operating costs. All power generated from the turbine was sent into the main utility grid and deducted from the district's electric bill.

BLADE LOST ITS BRAKE
A week before the breakdown, a maintenance worker noticed that the aerodynamic brake on one of three turbine blades had broken off. The brake is a tip section that can be turned 90 degrees, using wind resistance to prevent the blades from rotating. It was not repaired and the turbine blades were not secured in the storm.

BROKEN PART LEADS TO BREAKDOWN
The accident caused by the broken blade tip brake shorted out electrical wiring in the equipment and damaged the turbine and generator casings. The generator was buried about 18 inches in the ground and a security fence was crushed.

GROWING EXPOSURES
The wind turbine breakdown shows the exposure of even small-scale renewable energy equipment and other small power generation systems. As more municipalities and businesses generate power, the risks will increase.