The collapse of a GE Energy 1.5 MW wind turbine early March 2009 at Noble Environmental Power's 97.5MW Altona Windpark in northeast New York state was originally attributed to the combination of a power outage affecting the entire wind plant and wiring problems in two turbines.
However, inspection has since revealed a wiring anomaly in two of the turbines that resulted in the pitch system not responding properly, causing their rotors to over speed.
The Commission's decision to take the matter further follows a report it received from investigators. The report's findings included the assertion that Noble was unable to "satisfactorily explain" the incorrect wiring found in two of its turbines.
Investigators also found a number of instances where "best practices may not have been followed" in terms of monitoring and compliance with manufacturer recommendations.
Speaking about the decision Commission chairman Garry Brown said: "This Commission takes very seriously its responsibility to ensure that the electric corporations it regulates provide safe and reliable electric service.
"As we continue to encourage and promote development of new wind farms in New York State to help us create greater amounts of renewable energy, we must make sure that those installing and operating wind turbines do so properly, and with all necessary safeguards in place."
Noble Environmental Power, LLC, the parent of Noble Altona, has 612 megawatts (MW) of wind projects in operation in New York, and an additional 216 MW under development. The firm is the largest wind energy developer in the state.