Substations and power stations produce a “tonal” noise at 50Hz and the harmonics of that frequency. Noise measurements were taken around a number of transformers and reactors in a power station with and without cooling fans operating and the data was imported into an environmental noise model “Soundplan” to determine firstly potential noise exceedances with state government noise criteria and then if there were noise exceedances, introduce noise controls into the model to ensure noise emissions will comply with state government legislation after the power station expansion was completed. The environmental model can be run under meteorologically neutral conditions or under adverse weather conditions to assess the acoustical effects of being “down wind” of the power station.