Consents are also sought for an associated sub-station, access roads and overhead line structures.
Protect Karangahake says the size of the project, and the potential impact on the landscape, cultural values and the environment raise concerns.
The group says the proposed turbines are taller than the Te Aroha Broadcasting Spire and standing taller than Mt Karangahake when in their intended position along the Kamai's ridge line and directly adjacent to the DOC Conservation land.
Glenn Starr, CEO of Ventus Energy says the ecology — in particular birds and native bats — has been the subject of extensive monitoring which began more than a decade ago in 2005.
"Modern turbines are larger than earlier models but extremely efficient, enabling generation of more power with fewer structures.
" Our turbines are located to capture the best wind resource so the wind farm can meet local and national energy demand through renewable energy.
"Each turbine has three rotors (arms) which, measured to the tips, equate to 180m and 207m respectively," he says.
The proposed site would cover about 1.5 per cent of the whole Kaimai Ranges and provide renewable energy to around 49,000 households in both Waikato and Bay of Plenty.
Protect Karangahake group says the proposed site is too close to DOC land.
"Industrialisation of this level, adjacent to this narrowest section of the ecological corridor, running from the Kaimais up through the Coromandel ranges would have an adverse environmental effect.
"Kaimai Wind Ltd states that mortality of native bird and bat life will increase with the implementation of the wind farm.
"This raises questions as to why the wind farm would be located alongside a remnant and narrow ecological corridor and conservation land," the group says.
Environmental consultancy company Kessels Ecology surveyed the site as part of an Ecological Effects Assessment report released in March.
The nationally threatened North Island long-tailed bat, known to be within the Kaimai Ranges, was detected during the surveys for this proposal, it says.
They conducted a 14-day survey in January 2013 and a near-month long in September/October 2015.
"In the 2015 survey 63 per cent (eight) of all of the surveyed sites contained long-tailed bats, while in the 2013 bat survey 55 per cent (11) of the sites contained bats.
"In total 59 per cent (19) of the surveyed sites detected bats," it says.
But the report does not support findings from the Supplementary Ecology report of June 2018 undertaken by Ecology New Zealand Ltd (ENZL), an ecology consultancy company.
Their survey shows bats were detected at 95 per cent of all surveyed sites previously surveyed by Kessels. "With the exception to the ABM 9 site [which has a malfunction], these confirmed the presence of bats in all areas previously surveyed by Kessels," it says.
ENZL says that other sites equipped with automated bat detectors (ABM) do not show the same results as Kessels.
ABMs capture a spectrogram image of ultrasound bat echolocation calls and recorded data from one hour before sunset to one hour after sunrise.
"Of particular note, surveys undertaken at the ABM 16 site by Kessels did not show any bat presence. In contrast, ENZL's survey indicated that this site displayed overall moderate bat activity, and within context of the site, the second highest area for bat activity.
"The results of the 2018 bat survey data obtained from ABM 02 and ABM 12 now confirm the presence of long-tailed bats in these areas and updates previous absence within the Kessels report," it says.
ENZL also indicates that risks for bats is "non-significant" based on previous surveys on operational wind farms.
No short-tailed bats were detected during ENZL and Kessels surveys, with the closest being around 70km away from the proposed site.
Both ENZL and Kessels state that migratory and resident birds may also use habitat and airspace over the wind farm site.
"Some of these bird species are regional to local migrants, such as South Island pied oystercatchers, bittern and North Island kaka, while others are long distance migrants, such as bartailed godwits.
"The site may provide a corridor along which seabird species migrate from Miranda to the Tauranga Harbour, Ohiwa Harbour, Maketu Estuary/ Kaituna River mouth and Waihi Estuary/Pukehina Spit region," Kessels says.
Glen Starr says that understanding the birdlife flight patterns and habitat is factored into the company's planning and mitigations.
"All turbines south of the transmission line were removed from the proposal because of potential impact on bats and we will widen the ecological corridor and increase bird and bat habitat with native plantings on more than 20ha of land adjacent to the existing DOC Reserve," he says.
