Oaklands Hill Wind Farm: Environment

Bat and avifauna monitoring program overview

Since Oaklands Hill Wind Farm became operational, an extensive bat and avifauna monitoring program has been implemented by specialist consultants in accordance with the planning permit.

A Bat and Avifauna Management Plan (BAM Plan) was prepared and the following sections describe the monitoring that has been completed to date.

If you would like more information, please contact our Community Engagement team on 1800 039 600 or email aglcommunity@agl.com.au

In response to comments from DELWP, an additional monitoring campaign was implemented which focused on the mortality of two threatened species: Brolga and Southern Bent-wing Bat. The first 12 months of mortality monitoring was completed from May 2019 to May 2020.

Key findings from the monitoring program include:

  • No threatened bird or bat species were found impacted by blades of wind turbines.
  • Results indicate that the likelihood of Brolga being impacted is extremely low – no Brolga have ever been observed on the wind farm site and there is also no suitable habitat on site.
  • 48 bird fatalities were found, Magpies and Brown Falcon were the most common species detected.
  • Two bat carcasses were found, a White-striped Freetail Bat and a Gould’s Wattled Bat.
  • Annual mortality calculated for large birds was zero.
  • Annual mortality of bats was estimated at 0.91 ± 0.66 bats per turbine, equating to a total of 29.12 ± 21.12 bats over all 32 turbines in 12 months.

Bird and Bat Mortality Monitoring – Oaklands Hill Wind Farm, May 2019 to May 2020 (PDF)

Bird and Bat Mortality Monitoring – Oaklands Hill Wind Farm, May 2019 to May 2021 (PDF)

To assess the risk of Brolgas colliding with wind turbines at the Oaklands Hill Wind Farm, a two-year monitoring program was implemented following completion of the wind farm. The monitoring was focussed on their abundance and spatial distribution within the vicinity of the wind farm.

Brolga surveys were completed from August 2012 to April 2014. Monitoring found that relatively few Brolgas utilise habitat within 10 km of the Oaklands Hill Wind Farm. Whilst a number of wetlands in the region are used as flocking sites by up to 200 Brolga at each site, all are located beyond 10 km from the wind farm. It is unlikely that the wind farm will impact the Brolga population due to the lack of suitable habitat on site and spatial distance from Brolga flocking sites.

Brolga Utilisation of habitat within the vicinity of Oaklands Hill Wind Farm 2012–2014 (PDF)

Following completion of the Oaklands Hill Wind Farm, monitoring of bird utilisation of the wind farm was implemented for a period of two years to examine any seasonal differences in the abundance and diversity of bird species.

The following reports cover Spring 2011 to Winter 2012 and Spring 2012 to Winter 2013.

Species observed in both years comprised common native and introduced farmland birds. Only one threatened species was identified in the two years of surveys, that being the Black Falcon which is listed as vulnerable under the Advisory List of Threatened Vertebrate Fauna in Victoria 2013. Most individuals observed were recorded as flying, or foraging and flying. There was no significant difference between morning, mid-day and afternoon in the abundance of individuals.

Monitoring of bat presence and activity was undertaken in autumn and spring prior to commissioning of the Oaklands Hill Wind Farm.

The aim of the monitoring program was to firstly determine the bat species present on site, particularly the presence of the EPBC listed Southern Bent-wing Bat (Miniopterus schreibersii bassanii), and examine their relative activity on the wind farm site, and secondly to identify which species were most likely to be impacted by the wind farm.

Surveys in both seasons did not record the presence of Miniopterus schreibersii at the wind farm, nor was this species recorded in a preliminary bat survey during November 2006 (Venosta 2007). It is possible that this species may use the site during periods of migration for example, but this would be expected to be infrequent. The Oaklands Hill Wind Farm is therefore unlikely to adversely impact the population of Miniopterus schreibersii in south west Victoria.

Overall bat activity near the top of the anemometry mast was significantly lower than near the base.

Noise monitoring

In March 2012, AGL completed voluntary, comprehensive noise testing around the Oaklands Hill Wind Farm in response to concerns raised by neighbouring residents.

The noise testing, performed by specialist noise consultants, tested for infrasound, amplitude modulation, low frequency noise and tonal noise at locations neighbouring the wind farm.

Testing demonstrated that all areas of sound were compliant with the strict regulatory requirements. However, some audible tones from the gear boxes were detected in certain low wind speed conditions (between 10-18 km/h). The operation of the wind farm was modified so that the turbines did not operate during these low wind conditions.

In addition, after consultation with several neighbours, AGL decided to voluntarily temporarily shut down several turbines on the Wind Farm from 8:00 pm to 7:00 am each night. Residents were advised this was a temporary measure until a permanent fix for the tonal noise could be made.

After a thorough investigation, the source of the tonal noise was identified, with the solution to fix the issue implemented from November 2013. This involved fitting each turbine with a gearbox dampener to remove the tonal noise that was occurring under low wind speed conditions.

Following the installation of the dampeners, the Oaklands Hill Wind Farm recommenced operating to its full capacity, with the turbines operating with no operating hour limitations.

Further testing was undertaken in November 2014 and May/June 2015, as well as in February/March, August/September and November/December 2017.

If you have any further questions regarding this or any other matter, please feel free to contact our Community Relations Team on 1800 039 600 or email AGLCommunity@agl.com.au and an AGL representative will be in contact.