Data Gaps Confound Efforts to Limit Harm to Bats Posed by Wind Farms

posted in: February 2017 | 0

When the U.S. Fish and Wildlife Service published its recovery plan for the endangered Hawaiian hoary bat in April 1998, it didn’t consider wind farms to be a threat to the species. At the time, potential threats included habitat loss, pesticide exposure, a decrease in prey availability, and, possibly, predation, according to the plan.

Times have certainly changed. In 2013, scientists estimated that from 2000 to 2011, between 650,000 and 1.3 million bats were killed at wind facilities in the United States and Canada, with hoary bats making up “the highest proportions of fatalities at most continental U.S. facilities,” a state guidance document on the bat states. Not only have wind farms been found to be a major cause of bat fatalities worldwide, their proliferation in Hawai`i is causing some worry among local resource managers, who are seeing bats being taken at unexpectedly high rates.

For example, the Kaheawa Wind Power facility on Maui began spinning its turbines in 2006 and it was expected that those 20 turbines would kill or injure no more than one bat per year. Using that rate, the company was permitted by the state and federal governments to kill up to 20 over the term of the project. By 2014, however, computer modeling showed that there was an 80 percent chance the facility had killed as many as 29 bats, based on a total of eight actual observed takes over the years.

The Kaheawa Wind Power II and Auwahi Wind Energy projects on Maui and the Kawailoa Wind Power project on O`ahu have all experienced the same situation, where modeling has shown that the bats are possibly being killed at a rate much higher than anticipated in their Habitat Conservation Plans (HCP) and associated Incidental Take Permits (ITP). As of now, only the Kahuku Wind Power project’s projected bat take is still within expected limits.

As a result of the higher-than-expected estimates of bat take, all but one of the wind projects have amended or are in the process of amending their HCPs and ITPs, which govern how many bats may be taken by a facility, the type of mitigation required to ensure that a given farm has no negative impact on the bat population, and the cost and timing of that mitigation.

The Kaheawa Wind Power project, again, as an example, received approval a little more than a year ago from the federal Fish and Wildlife Service and the state Department of Land and Natural Resources’ Division of Forestry and Wildlife to amend its HCP and ITP to increase its allowable take of bats from 20 to 50. And more amendments to other plans are pending: Kaheawa Wind Power II is seeking to increase its allowable take by 69 bats, for a total of 80, Kawailoa is seeking to add another tier of mitigation and at least 55 bat to its allowable take, and Auwahi has proposed changing the way bat kills are estimated so the numbers won’t be so high.

But how many is too many killed or injured bats? And how much mitigation by means of forest restoration is enough to negate any negative population impacts? DOFAW Maui branch manager Scott Fretz told the state’s Endangered Species Recovery Committee (ESRC) back in September 2015, as it was in the midst of adopting its guidance document on how to best manage threats to the bat, that the bat take being requested by wind farms “is getting alarmingly high. There is so much we don’t know about mitigation. It raises the question if we are really creating a net benefit for such high levels of take.”

According to Jodi Charrier, a biologist with the Fish and Wildlife Service, there currently are no definitive answers to those questions. Knowing whether or not the rate at which wind farms are killing bats is jeopardizing the species’ population is “one of the greatest challenges to clearly connect the dots with our logic,” she told Environment Hawai`i. She added that her agency uses the best available science to guide its actions with regard to the tiny, tree-dwelling animals, but admits that knowledge about them is limited.

While it’s known that the bats are widely distributed on all of the main Hawaiian islands, “there is no valid estimate of the population and there are no tools or methods to determine it. It’s the same for hoary bats on the mainland,” she said. Cave-dwelling bats can be counted relatively easily, while tree-dwelling bats are challenging to count and to catch, she said.

“They’re a cryptic species,” she said, noting, however, that resource managers and the wind farms have recently started a major bat research blitz. Contracts for work seeking to better assess the population and identify the bats’ habitat and diet, among other things, are just now being put into place and it will be two to five years before any results are ready, she said.

In the meantime, the turbines for all of the state’s wind farms keep spinning, even those for the ones that have exceeded their allowable take. Under the Endangered Species Act, a violation of the terms of an incidental take permit would result in an illegal take under section 9 of the act. However, if the violation is deemed technical or inadvertent, the FWS “may send the permittee a notice of noncompliance by certified mail or may recommend alternative actions to the permittee so that they may regain compliance with the terms of the permit,” according to a fact sheet on the ESA posted online by the Fish and Wildlife Service. In the case of the Hawai`i wind farms, Charrier said that her agency and DOFAW are simply working with the facilities on amending their HCPs and take permits, which can take up to two years to complete.

$50K Per Bat

The state’s five active wind farms together produce as much as 171 megawatts of electricity, and the three more — Na Pua Makani on O`ahu, and Lalamilo and Pakini Nui on Hawai`i island — that are in the pipeline will have the collective ability to produce another 49.3 MW, for a total of more than 200 MW. And given the state’s new goal of producing 100 percent of its electricity with renewable energy by 2045, the Hawaiian Electric Company is actively seeking developers to construct even more wind energy projects on O`ahu before federal tax credits expire.

The additional turbines, if constructed, will no doubt result in more bats being taken. So how much will these facilities have to pay to mitigate its bat takes? Under the current policy adopted by the ESRC: $50,000 a bat, at least for the next few years.

Over the years, the existing wind facilities together have spent millions of dollars on research and on-the-ground mitigation (most often restoration activities to increase or enhance forested and foraging areas), in addition to choosing to slow their turbines when there is little wind to a speed that studies have shown significantly reduces the likelihood of harming bats. But the mitigation done so far has been inconsistent among the facilities, according to the bat guidance document.

New ecological information often leads to changes in recommended mitigation, resulting in “an unpredictable scale and cost of mitigation, making it difficult to measure the impact on species recovery across a large number of disparate projects,” it states. It goes on to note that in the HCPs for the five wind farms and the three in development, restoration efforts ranged from 13 acres to 40 acres per bat, and costs ranged from $10,000 to $87,000 per bat. “One HCP mitigated by providing funding for research at a cost of $1,000 per bat,” the document states.

That may no longer be the case now that the ESRC, in adopting its guidance document, has endorsed a rate of $50,000 per bat when calculating mitigation costs, at least until the guidance document is revised again. The amount spent on bat mitigation had averaged nearly $50,000 per bat, but the committee also took into account estimated watershed restoration costs of the state’s Rain Follows the Forest Initiative (between $35,708 and $68,415 to restore 40 acres) and costs associated with managing the state’s forest reserves, Natural Area Reserves and wetlands for which restoration costs can run anywhere from $40,000 to more than $80,000 per 40-acre tract — assuming 40 acres per bat for forest projects.

The cost-per-animal standard is only meant to be temporary, however. The ESRC plans to revise is bat guidance document every five years. And as new information is gathered that can help refine mitigation efforts, that standard may change.

“It’s the actual biological return that counts. … The dollar [per animal standard] is just an arbitrary thing,” said ESRC member Jim Jacobi at the committee’s meeting last December.

Helemano Acquisition

For now, the requirement that wind farms pay $50,000 for every bat that is anticipated to be taken may assist in the state’s years-long effort to obtain four parcels totaling roughly 3,000 acres at Helemano, O`ahu owned by Dole Food Company. Kawailoa Wind Power in December briefed the ESRC on its proposal to contribute $2.75 million toward the purchase of the lands by the state. Last year, the Board of Land and Natural Resources agreed to use $1.5 million in Legacy Land Conservation Program funds to help with the purchase.

The total purchase price is expected to be around $15 million, and the state Department of Land and Natural Resources, the U.S. Department of Defense, the U.S. Department of Agriculture, the City and County of Honolulu, and the Fish and Wildlife Service have all either committed or expressed interest in contributing funds. The proposed contribution from Kawailoa would all but seal the deal.

The Kawailoa facility is by far the largest wind farm in the state, with 30 turbines and the capacity to generate nearly 70 MW of electricity. In addition, it has probably taken the most bats. Currently, the HCP and ITP for the facility allow for the take of up to 60 bats over the 20-year life of the project, and it has already been estimated to have taken up to 54 in its first few years of operation. The company now seeks to amend its HCP to allow for the take of at least an additional 55 bats. At $50,000 for each additional bat to be taken under the new HCP (if approved), that works out to $2.75 million.

At the ESRC’s December meeting, DOFAW O`ahu branch manager Marigold Zoll explained that the acquisition of the Helemano lands would secure the state’s access to its Poamoho ridge trail and `Ewa forest reserve, where there is great potential for public recreation, silviculture, and intense forest management. Sale of the lands to a third party would terminate the state’s access and also hamper bat take mitigation efforts in the area, she said.

She noted that bats have been detected in all of the lands surrounding the Dole properties and likely occur on Dole lands, as well. One of the parcels, which is zoned for agriculture, could be farmed for native plant production and timber products and be managed so that it serves the bat’s habitat needs for its various life stages, she said.

“If bats like a certain type of tree with certain spacing, we could plant that,” she said. “It really has a lot of possibilities as far as using the latest research of what bats need.”

She noted that under a sales agreement with Dole, the state had six months to secure the money to buy the lands. “The funds [from Kawailoa] would provide a critical source of funding to close the project,” she said, adding that she doubted whether the state could buy only some of the parcels if the Kawailoa money wasn’t available to help buy all four.

While some committee members expressed concern over the other potential competing uses of the property — recreation. timber harvesting, etc. — a representative from the Fish and Wildlife Service noted that it has contributed $2 million toward the acquisition and feels that the benefits to the bats outweigh any potential negative impacts.

Although the committee was not slated to vote on whether the land acquisition was an acceptable new mitigation measure for the HCP, Kawailoa representatives said the company needed some idea of the committee’s leanings because it was planning to commit the funds very soon.

Committee member Jacobi said he supported the concept of the acquisition, but “we don’t have a good formula yet on how to produce more bats with a certain kind of management action. If we were at that point, we would probably have some concerns in terms of if we really could ramp this up as a good bat production zone, its potential impacts with the Kawailoa wind farm and ones in that general area.”

The Hawaiian hoary bat has been found to travel as many as 12 miles in one night, and Jacobi suggested that he and some of his colleagues at the U.S. Geological Survey are concerned that mitigation areas may not be far enough away from the wind farms to be fully effective.

“We would really urge as we learn more about bats and how to manage for them and produce them … that we come up with a strategy on how to determine where to do those best relative to other current or proposed areas where they may run into that kind of interaction. It’s not an issue now, but is something we need to consider as we move along the bat track,” he said.

The committee as a whole expressed its general support of the acquisition. The FWS’s Charrier later told Environment Hawai`i that Kawailoa was still committed to funding the project, but was awaiting the issuance of a support letter from her agency, which she indicated was forthcoming.

Alternate Accounting

At the same December ESRC meeting where Kawailoa presented its proposal, representatives of the Auwahi wind farm briefed the committee on its suggestion about changing the way the computer model used to estimate potential bat takes is applied so that the numbers aren’t so high.

The model, developed by the FWS and applied only in the past few years, takes into account the observed bat take, as well as the many variables that can influence whether or not a search team finds observable evidence of a bat take: the terrain surrounding the turbines, the amount of time a bat carcass is likely to persist in the environment, the efficacy of the search effort, etc. The model produces a range of potential bat take scenarios and assigns a confidence level to each one. Erring on the side of caution, the FWS and DOFAW have advised the wind farm to select the bat take scenario that has a confidence level of 80 percent.

In the case of the Auwahi wind farm, the model has found that there is an 80 percent chance that the turbines have killed as many as 23 bats as of last June. The farm’s current take limit is 19. Had the FWS been willing to accept a confidence level of 50 percent, the estimated take would have been lower, and Auwahi has suggested that that level should be acceptable for annual bat take estimates.

“The basis for 80 percent, the statistical rationale, hasn’t really ever been explained to us,” Auwahi biologist Marie VanZandt told the committee. Her company has been in the process of amending its HCP and ITP for the past two years because of its higher-than-expected bat take estimates. “We want to provide confidence that our take limit isn’t going to be exceeded. We want to ensure we don’t have to go through a second amendment.”

She added that she had an obligation to not overestimate the wind farm’s bat take and thereby misrepresent to the public the facility’s impacts.

Tom Snetsinger of Tetra Tech, a consultant to Auwahi, pointed out two ways in which the FWS may be overestimating the number of bats taken: 1) the model is unable to factor in the effect that curtailing turbine speed during low-wind (which most of the Hawai`i wind farms are now doing) has on the number of bats taken; and 2) a recent study suggests that models may be underestimating how long bat carcasses persist in the environment and thereby are overestimating the level of unobserved take. With regard to the confidence standards set by the FWS and DOFAW, he explained that the company still planned to use the 80 percent credibility level to determine the upper limit of take overall, but in terms of monitoring annual takes, it wanted to use a “central tendency” or median value that it believed better reflected actual take.

His explanation of why using a median — or 50 percent — value was the best way to measure compliance with the ITP seemed difficult for some committee members and agency staff members to grasp.

One FWS staffer who did understand Snetsinger’s proposal noted that if a median confidence value is used, “50 percent of the time, you’ll be under-mitigating, 50 percent of the time you’ll be over-mitigating.”

“That seems like the opposite of confidence. That’s no confidence,” DOFAW’s Fretz said.

DOFAW’s Kate Cullison conceded in written comments on the proposal that by “spreading mitigation based on the 50 percent credibility level across multiple projects, the law of probability suggests that you will be close to the actual need or target. While this is a sound and well-documented approach for aggregated systems, it differs from the present situation in Hawai`i.”

First, there is no aggregated system of wind farms in Hawai`i. Each facility has its own unique HCP. Second, she stated, the “50 percent” approach assumes that a bat taken at one facility is equivalent to one taken at another. “Thus, if take is underestimated and subsequently under-mitigated for at one site, the deficit will likely be made up by mitigation at another site,” she wrote, adding that this may not be the case in Hawai`i, where preliminary studies suggest there are two genetically distinct groups of bats in Hawai`i.

The committee ultimately recommended that Auwahi representatives work with FWS and DOFAW staff on preparing a one-page explanation, with examples of how the new standard would be applied, for its next meeting.

“I fully support the concept of exploring new territory. If we’re going to change to something, let’s have a logical reason to change. … I would not like to see this drag out over the next six months,” Jacobi said.

While the committee has not yet reconvened to discuss the matter further, Charrier told Environment Hawai`i that her agency and DOFAW, at least, still believe the 80 percent standard is appropriate.

As Cullison wrote, “The core difference between the outputs at 50 percent and 80 percent is due to uncertainty. If the wildlife agencies were to use the 50 percent as the estimated take rather than the current standard of 80 percent, and the actual take was above the 50 percent output, then the result is largely manifested as a delay, which will result in a deficit in lost productivity that may not be regained.”

— Teresa Dawson

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