Facilities – Solar Plant
In this decision, the AUC approved the application from Aura Power Renewables Ltd. (“Aura”) to amend the previously approved 75-megawatt (“MW”) solar plant designated as the Fox Coulee Solar Project (the ”Power Plant”).
Application Details
In Approval 23951-D02-2019, the AUC approved the Power Plant four kilometres north of the Town of Drumheller, in Starland County, directly adjacent to the Drumheller Municipal Airport (“the Airport”).
In this application, Aura applied for approval to amend the power plant to utilize a combination of fixed-tilt and single-axis tracking solar panels, change the model and total number of inverter transformers used in the power plant, and remove the battery storage units. Aura later filed an update to its amendment application to change the configuration of the proposed solar panels from two panels in portrait layout, to one panel in portrait layout. Aura also proposed the exclusive use of single-axis tracking solar panels, rather than a combination of single-axis tracking panels and fixed-tilt panels.
The Power Plant would consist of 207,714 single-axis tracking solar photovoltaic panels and 18 inverter transformer pairs and would have a total generating capability of 75 MW. A solar glare report was completed by Green Cat Renewables Canada Corporation (“Green Cat”) for the project for Aura. Green Cat concluded that there would be a glare impact to pilots using the southbound flight path approaching the Airport. Aura committed to implement the mitigation plan developed by Green Cat to eliminate the yellow-grade glare along the southbound flight path.
Intervener Submissions
Solas Energy Consulting Inc. (“Solas”) submitted a solar glare report on behalf of the Solar Opposition Participants Group (”SOP”). The SOP argued that Aura’s proposed mitigation plan would not address all the predicted solar glare impacts. Given the potential public safety risk to pilots, the SOP requested that the AUC deny the application. Should the application be approved, the SOP requested that a number of conditions were imposed, including that Aura comply with a mitigation plan developed by Solas.
The Town of Drumheller (the “Town”) argued that the project was in violation of the Canadian Aviation Regulations. The Town also submitted that the perception of increased risk to pilots resulting from the project would have economic impacts for local industries that relied on the Airport.
Scope of the Decision and Inclusion of Flight Routes
In its report, Solas evaluated 29 flight routes, which represented various landing, takeoff and circling approached to the Airport, including one flight path that had not been considered in the original proceeding (“FP5”). The SOP noted that the Airport was an uncontrolled aerodrome, and pilots were required to rely on a “see or be seen” principle for takeoff, landing and performing circling approach flight circuits. The SOP argued that consideration of the flight paths and flight routes would be critical to evaluating the risks associated with solar glare for local pilots.
Aura submitted that inclusion of FP5 and other flight routes was beyond the scope of the amendment application and that there was no need for the AUC to consider any route beyond those assessed in the original proceeding.
Standard Flight Paths and Circling Approaches
The AUC noted that, while not determinative, expert evidence in the original proceeding which had relied on United States Federal Aviation Administration (“FAA”) guidelines was instructive in determining what constitutes a standard flight path. The AUC had identified FP1 through FP4 are standard takeoff or landing flight paths and found that FP1 and FP2 were in regular and common use. However, evidence in this proceeding did not support that FP5 or any of the other new flight routes corresponded with the FAA definition of “final approach path”. It was also not established that they were in common or regular use.
The AUC noted that the SOP provided little information explaining the usership or the frequency of use of these flight routes in this proceeding and, more significantly, no such evidence was provided in the original proceeding.
Despite unsatisfactory responses from the SOP to an AUC request for more information on why the new flight routes had not been raised in the original proceeding, the AUC recognized the public interest benefit in considering factors recommended by Transport Canada. In these circumstances, this included circling approaches. The AUC concluded that Circ1Large was the only newly introduced flight route with a reasonable basis of inclusion in this proceeding.
Incremental Yellow-Grade Glare
The AUC considered whether FP1 through FP4 and Circ1Large were expected to experience incremental yellow-grade glare as a result of the amendments. Evidence provided by Solas indicated that only FP2 and Circ1Large would experience an increase in yellow-grade glare as a result of the project, as compared to the original approval.
The AUC determined that only FP2 and Circ1Large fell within the scope of the proceeding.
FP2 and Circ1Large
Glare Impacts to Pilots Using FP2
The AUC was not persuaded that a +/- 15 degree range suggested by Green Cat as being sufficient to address glare that could affect pilot safety. The AUC determined that the evidence suggested that a +/- 50 degree range, as supported by Solas, was conservative; however, in the absence of a detailed mitigation plan for angles between +/-15 degrees and +/-50 degrees, the AUC found it reasonable and in the public interest to accept the mitigation plan that corresponds to the +/- 50 degree viewing angle range. This was based on the FAA study’s conclusion that yellow-grade glare adversely affects pilots within a +/- 25 degree viewing angle range and the AUC’s interpretation of the FAA recommendations that yellow-grade glare would have the potential to adversely affect pilots between 25 and 50 degrees. Accordingly, to ensure that there is no yellow-grade glare along FP2, the AUC required that Aura implement software controls on the solar panels within subarrays 17, 18 and 19, as stipulated in the mitigation plan for the removal of yellow-grade glare on the southbound flight path prepared by Solas based on a horizontal viewing angle range of +/- 50 degrees.
Glare Impacts to Pilots Using Circ1Large
Green Cat predicted there would be no glare on Circ1Large. Solas predicted up to 35,507 minutes of yellow-grade glare along the flight circuit.
While the AUC noted that it found a +/- 15 degree horizontal viewing angle insufficient to address glare that could affect pilot safety, it found it unnecessary to make findings in this proceeding on the preferred methodology when modelling flight circuits or confirming the amount of yellow-grade glare expected on Circ1Large.
The AUC was satisfied that while specific software mitigation was required to eliminate yellow-grade glare along FP2, the glare impact to pilots on Circ1Large could reasonably and effectively be mitigated by the use of adequate sunglasses and that the implementation of software controls was not required. While the AUC acknowledged that pilots were not required to wear sunglasses or carry them on their flights, it noted that this was consistently recommended by aviation authorities and sunglasses were a common aviation item.
Other Findings
The AUC determined that a participant involvement program had been conducted before a facility application was filed with the AUC. Therefore, the technical aspects of the Power Plant amendment met the requirements of Rule 007.
The AUC found that Aura’s project-specific mailout in respect of the amendment application allowed potentially affected stakeholders, including the SOP members, to understand the nature of the application well enough to identify any specific areas of concern. Regarding the SOP’s concern that the project mailout did not specifically identify the change in solar glare modelling parameters, the AUC noted that this degree of detail was not generally required at this level of notification.
As Rule 033: Post-approval Monitoring Requirements for Wind and Solar Power Plants had come into effect and applied to the project, the AUC noted that Aura was required to comply with the requirements of Rule 033. Accordingly, the AUC imposed, as a further condition to the approval, that Aura submit an annual post-construction monitoring survey report to Alberta Environment and Parks (“AEP”) and the AUC within 13 months of the project becoming operational, and on or before the same date every subsequent year for which AEP requires surveys pursuant to section 3(3) of Rule 033.
