Wind farm plan aims to reduce Hawaiian bats deaths By Nina Wu

Kawailoa Wind, the state’s largest wind farm on Oahu’s North Shore, announced today that it has invested in a system to deter Hawaii’s endangered bats from flying into the turbines.


Technicians installed bat deterrent systems on Kawailoa Wind’s turbines to reduce Hawaiian hoary bat deaths.

The 30 wind turbines at the 69-megawatt farm, which is owned by D.E. Shaw Renewable Investments LLC, has caused a higher-than-expected number of bat deaths. The Hawaiian hoary bat, or opeapea, is the only land mammal native to Hawaii and has been listed as an endangered species since 1970, according to guidance documents prepared for the state’s Division of Forestry and Wild Life. It is primarily threatened by collisions with wind turbines, wire fences and communication towers.

The deterrent system, manufactured by NRG Systems Inc. in Vermont, emits an ultrasonic acoustic field in the same range as the bats’ natural calling frequencies. The system interferes with the bat’s ability to receive and interpret its own echolocation calls, thereby discouraging it from entering the airspace around the wind turbines.

NRG said it is similar to the use of white noise machines to mask unwanted sounds.

Kawailoa Wind is the first wind farm to commercially purchase the system from NRG Systems, according to environmental compliance manager Brita Woeck. She declined to say how much money was invested, but said Kawailoa was eager to give the pioneering technology a try in Hawaii.

“It’s really exciting,” said Woeck. “The results of testing on the mainland are really promising. We think it’s a tool that holds tremendous promise for Kawailoa right now.”

D.E. Shaw, which has solar and wind projects across the U.S., including the nation’s first offshore wind farm off of Rhode Island, has historically adopted innovative technologies to mitigate the impacts of renewable energy development, CEO Bryan Martin said in a news release.

Crews began installing the systems this week, and will place them on all 30 turbines at Kawailoa.

While installing the new systems, Kawailoa is at also seeking to amend its draft “habitat conservation plan” to include the “incidental take,” or accidental killings, of Hawaiian hoary bats to 265, significantly more than its current allowed take of 60.

The first plan was based on the best available estimate at the time seven years ago, the draft said, but the take has been higher than anticipated.

The requested take in Kawailoa’s new draft plan does not take into account the implementation of the new bat deterrent system, said Woeck, but the company wanted to go ahead and install the systems.

Three other wind farms – Auwahi and Kaheawa Wind Power II on Maui and Pakini Nui Wind Farm on Hawaii island — are also seeking to increase their “incidental take” of Hawaiian hoary bats in amendments to their existing plans.

Auwahi wants to increase its take to 140, up from 21. Kaheawa Wind Power II wants to increase its take of bats to 38 from 11. Pakini Nui, which drafted its first, plan, wants approval for a take of 26 bats.

The plans, which also address the take of endangered nene and Hawaiian petrels, are open to comments at public meetings scheduled by the U.S. Fish and Wildlife Service next week on Oahu, Maui and Hawaii island. The USFWS is seeking public comments through June 10.

Currently, Kawailoa is curtailing, or turning off its turbines, during low wind speeds and at night, when bats are most active, to minimize fatalities. The bat deterrent systems will be used in addition to curtailment efforts.


The U.S. Fish and Wildlife Service is seeking public comment on the draft EIS for four wind farms regarding endangered species through June 10.

Public meetings

>> Oahu: 6 to 8 p.m. Tuesday, Waialua Elementary School, 67-020 Waialua Beach Road.

>> Maui: 6 to 8 p.m. Wednesday, Kula Elementary School, 5000 Kula Highway

>> Hawaii: 6 to 8 p.m May 23, Naalehu Community Center, 95-5635 Mamalahoa Highway

Written comments can also be sent to Field Supervisor, U.S. Fish and Wildlife Service, Pacific Islands Fish and Wildlife Office, 300 Ala Moana Blvd., 3–122, Honolulu, HI 96850 or to

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