CLIENT

Edison Mission Energy

PROJECT DESCRIPTION

The Elkhorn Wind Farm is located in rural Nebraska in a predominantly agricultural area with rolling hills. The closest residence is approximately 1,000 feet northwest of one of the turbines and the second closest is approximately 5,000 feet west of another turbine. There are a total of 27 turbines in the Wind Farm, each rated at 3 MW. Edison Mission Energy had received noise complaints from nearby residents.

SCOPE OF WORK

INNOVA was hired to conduct compliance sound level testing at the nearest sensitive receivers and generate a computer model predicting sound levels in the wider area. Sound level measurements were recorded in both the near-field and far-field. INNOVA’s measurements, analysis and modeling identified the aerodynamic noise caused by rotor blade rotation as the primary noise source. The noise level at the nearest sensitive receiver was in excess of 10dB above the background ambient level. 

ACOUSTICAL REQUIREMENTS

Neither the state of Nebraska nor the city of Bloomfield had noise regulations that pertained to the Elkhorn wind farm. In the absence of an applicable regulation, a sound pressure level of 5 dB above the background ambient level was mutually agreed as the noise target at the nearest occupied dwelling.

NOISE SOURCES

27x 3 MW Vestas V90 wind turbines

UNIQUE PROJECT HURDLES

Access to nearby residents’ properties for compliance measurement purposes was not always granted and therefore other representative locations needed to be chosen.