Wind Projects – Rule 012 – Noise Control
In this decision, the AUC considered whether to approve applications from EDP Renewables SH Project GP Ltd. (“EDP”) for amendments to a power plant and substation, collectively designated as the Sharp Hills Wind Project. The AUC found that approval of the proposed amendments to the project were in the public interest.
Amendment application description
EDP had approval to construct and operate the Sharp Hills Wind Project in the New Brigden and Sedalia areas.
On March 8, 2019, EDP filed applications with the AUC for approval to amend the Sharp Hills Wind Project, including alterations to the Sharp Hills Wind Farm and the Sedalia 363S Substation. Specifically, EDP applied for amendments including a change in turbine model. As a result, 12 turbines were removed from the original project layout and adjustments were made to the collector system, access roads and transformers in the Sedalia 363S Substation. EDP also adjusted the project to be developed in two phases.
Issues raised in the proceeding
The AUC’s recent amendments to Rule 012 – Noise Control came into effect on August 1, 2019. One of the amendments found in the current version of Rule 012 is a new section (section 2.6) that expressly addresses ambient sound levels (“ASLs”).
The previous and current versions of Rule 012 give applicants two options for establishing ASLs and permissible sound levels (“PSLs”) at receptors:
-
if the assumed ASLs and PSLs set out in Table 1 of Rule 012 are representative of the project study area (at receptors), an applicant may use those assumed values; and
-
if the project area is located in a pristine area or an unusually noisy area and the assumed ASLs and PSLs set out in Table 1 of Rule 012 are not representative of the project study area (at receptors), an applicant can rely on measurements to determine the ASL. Where a measured ASL is used, a Class A2 adjustment (also called an ambient monitoring adjustment) is established based on the measured ASL and then applied to the PSL.
The primary issue raised in this proceeding was whether it was reasonable for EDP to use an assumed nighttime ASL of 35 dBA (based on Table 1 of Rule 012) when calculating the PSLs at various receptors in the project area.
AUC findings
The AUC noted that Rule 012 originated with Alberta Energy Regulator Directive 038: Noise Control. Directive 038 sets an assumed nighttime ASL of 35 dBA for rural areas and states, “[b]ased on research conducted by the Environment Council of Alberta, the average rural ambient sound level in Alberta is about 35 dBA at night.”
Assumed ASLs can be used by applicants, and Directive 038 notes that the only two cases where it may be necessary to determine ambient sound level are areas considered to be pristine and areas with non-energy industrial activity that would impact the background noise levels.
Rule 012’s definition of pristine area is “a natural area that might have a dwelling but no industrial presence, including energy, agricultural, forestry, manufacturing, recreational or other industries that affect the noise environment.”
The intervenors argued that their area was pristine, and that downward adjustments to the ASL was required based on the sound study that had been conducted by their expert.
The AUC found that the evidence presented by the intervenors was not sufficient to demonstrate that the project area was pristine or that the ASL in the project area was materially different than other parts of rural Alberta, where oil and gas and agricultural activities also take place.
Rather, the AUC found EDP’s description of the project area as “typical of rural Alberta with predominate agricultural and energy industry land use” to be accurate. Given the presence of agricultural and oil and gas activities throughout the project area, the AUC found that it was reasonable for EDP to conclude that the assumed ASLs based on Table 1 of Rule 012 were representative of the project area.
Representative conditions for the measurement of ambient sound levels
The AUC provided further comment on measurement duration and data transferability. It found that 24 hours of measurement data was inadequate to establish representative ASLs in circumstances where there were no constant dominant sound sources.
With regard to data transferability, the AUC noted that Rule 023 allows measurement data collected at one receptor to be used to establish ASLs at other receptors in a similar acoustic environment. However, in this case, there was inadequate measurement duration, and there were other questions regarding whether data measured at one location was representative of another location.
Rule 12 compliance and noise impacts
The AUC found that the use of assumed ASLs based on Table 1 of Rule 012 was appropriate for these applications, and the nighttime PSL for the affected receptors, including the intervener residences, was 40 dBA (5 dBA above the ASL). Based on the results of the project Noise Impact Assessment, the AUC found that cumulative sound levels at all affected noise receptors will likely comply with that nighttime PSL.
Post-construction comprehensive sound level surveys
Given the concerns raised by intervenors, the AUC required that EDP complete a comprehensive sound level survey to verify compliance with Rule 012 once the project commences operation.
