Above rugged, mountainous terrain just outside of Tumbler Ridge, BC, the blades of 61 General Electric turbines spin wind into electricity. These turbines are Meikle Wind, the province’s largest wind energy facility. It generates enough electricity to power 54,000 homes every year.
During the project’s development stage, BKL was hired to conduct a construction and operations noise assessment in accordance with BC’s Environmental Assessment Act (BCEAA). BKL’s goal was to predict future noise levels and determine if operations noise from Meikle Wind could affect humans and wildlife in the area.
The province’s noise guidelines for wind power projects are limited to human receivers and don’t adequately address a number of important variables that can affect the results of noise predictions. Examples of these variables include terrain shielding, sound power uncertainty, and amplification across valleys. Therefore, in addition the provincial guidelines, BKL also applied international criteria and best practices on noise modelling to ensure its assessment accounted for all variables.
You can read more about interpreting and critiquing BC’s acoustical guidelines for wind power noise in BKL’s paper on the subject, which was published by the Canadian Acoustical Association in 2016.
For Meikle Wind, BKL’s acoustical team created a 3-D model that incorporated all nearby noise-sensitive human receivers, as well as wildlife habitat areas. While the nearest permanent residences are 33 kilometers from the wind farm, the closest human receiver scoped into the project was a campground at Gwillim Lake, around 6 kilometres from the nearest turbine. Sensitive wildlife habitat, however, was much closer to the proposed turbine locations. To assess noise levels on wildlife, BKL located receivers in its computer model to account for caribou, deer, elk, moose, and breeding bird habitat areas. Later, when the project changed the quantity and model of turbines, BKL updated its 3-D model and factored in the variation in octave band sound power levels between turbine models. Once all the updates were included, the study showed that noise levels would be lower by 1–2 dBA.
After identifying and accounting for limitations in the provincial guidelines for assessing wind power noise, BKL conducted a thorough environmental noise assessment. BKL’s noise predictions supported the project’s successful application for an Environmental Assessment Certificate. Today Meikle Wind is fully operational, delivering up to 180 megawatts of clean electricity to BC’s grid.