Wind farms killing more bats than expected

As wind farms statewide are killing more Hawaiian hoary bats than expected, a Maui wind farm is asking the state to increase the number of endangered bats and nenes it’s allowed to incidentally kill.

Kaheawa Wind Power II, a 21-megawatt generation facility that ascends the slopes of the West Maui Mountains above Maalaea, wants to increase its number of permitted bat fatalities from 11 to 62 adults and nene fatalities from 30 to 48 adults over the next 15 years. It has already exceeded its bat permitted fatalities.

“The proposed rates of take are expected to be minor relative to the total population of these species on Maui,” Maryland-based KWP II owner Terraform Power said in a statement, citing public records. “The mitigation measures . . . are designed to more than offset these effects and result in a net benefit to both species.”

But because research on both wind energy and bats is still evolving, setting ground rules is a tricky game for those who support both clean energy and wildlife protections.

“I think most of us who track native wildlife are concerned that these trends are starting to show up,” said Lucienne de Naie, conservation chairwoman of the Sierra Club Maui Group. “We’ve just got to know more as soon as possible to allow the wind farms and the creatures to co-exist.”

The ‘ope’ape’a or Hawaiian hoary bat is Hawaii’s only native terrestrial mammal, according to the state Department of Land and Natural Resources. The brown-and-gray furry creatures have white-tinged hair and ears, hence the name “hoary” or frosted.

Very little is known about the habitat and population of the ‘ope’ape’a, which is a subspecies of the North American hoary bat. Research suggests the solitary creature roosts among trees in areas near forests and feeds on native and non-native night-flying insects, according to the U.S. Fish and Wildlife Service.

Population estimates across the islands have ranged from hundreds to a few thousand, but this has been based on limited data. Nonetheless, the hoary bat was listed as a federal endangered species in October 1970.

KWP II is among several Hawaii wind farms that have been claiming more Hawaiian hoary bat lives than expected. According to a DLNR report, an estimated 19 bats and nine nenes have been killed at KWP II as of last June, five years into its 20-year permit.

At Kaheawa Wind Power I, higher up the slope at Maalaea and also owned by Terraform, an estimated 34 bats and 41 nenes have been killed since 2006. It’s permitted take by 2026 is 50 for bats and 60 for nene.

And Auwahi, operated by Sempra U.S. Gas & Power on the southern slopes of Haleakala, has recorded an estimated 23 bat fatalities since 2012. Its maximum take is 27 bats by 2037.

In total, Hawaii’s five wind major wind farms are allowed 180 incidental bat deaths. However, they’ve already hit 146, and most are barely five years into their 20-year permits.

As far as the company knows, all fatalities happened because of direct collisions with spinning turbines, Terraform said. Researchers aren’t sure why most bats collide with turbines, though theories include “attraction to insects caught in turbine vortices, warmth, acoustics or mistaking turbines for roost trees.”

Nene collisions are generally attributed to in-flight misjudgment. Once or twice a week, KWP II employees search the ground around the turbines for downed wildlife.

Fatalities may simply be higher than expected because people are getting better at finding them, Terraform said. Measures, such as using specially trained dogs and setting traps for animals that generally carry off the bat carcasses, also have “resulted in higher rates of detection.”

De Naie saw two possible reasons.

“One is that they totally underestimated the lethal power of these machines and the creatures can’t escape them,” de Naie said. “The other is that this is what has been happening all along, but . . . we hadn’t done very much research and didn’t know what the levels were going to be.”

Read more at The Maui News