The following has been adapted from an executive summary of a resource published by the Canadian Wind Energy Association (CanWEA) to summarize bat conservation in the Canadian wind industry. Published in August, “Wind Energy and Bat Conservation – A Review by the Canadian Wind Energy Association” is the result of a three-year scientific review by CanWEA, DNV GL and Natural Resource Solutions Inc.
Wind energy has become the largest source of new electricity generation in Canada over the last decade. Wind energy is a near-zero-emission energy source that can help reduce greenhouse-gas emissions from the electricity sector. At the same time, concern about the potential impacts of wind energy on bats has increased with the rapid pace of wind development across Canada, the U.S. and Europe.
Whereas it is generally recognized that wind energy facilities pose a lower risk to bat population sustainability than other sources of bat mortality – including white-nose syndrome (WNS), environmental contaminants, habitat loss and the ongoing impacts of climate change – the wind industry recognizes that wind energy facilities can have direct and indirect effects on bats and their habitats and continues to seek ways to avoid or minimize these impacts.
Regulatory agencies in several Canadian jurisdictions have taken steps to establish guidelines and protocols to minimize potential impacts to bats. Although it is appealing to have standardized approaches to avoidance and minimization, these guidelines are often based on the findings of a limited number of early bat studies in the U.S. or other regions with different ecological conditions.
The goal of the review is to provide current information and an adaptive management approach that incorporates new research and technology into the development of effective strategies to conserve bat populations. Therefore, this review has the following objectives:
1) Facilitate sound policy discussions and flexible mitigation plans across the country;
2) Provide avoidance and minimization and compensation options for varying circumstances;
3) Enhance existing information in order to drive science-based policy decisions; and
4) Support updates and revisions of provincial and/or federal guidelines pertaining to bats and wind energy.
Siting and Development Considerations
The avoidance and minimization of impacts to bats begins at the siting stage of development. Information on bat communities, population numbers, habitat preferences, foraging and breeding behaviors, key habitat features, seasonal trends, and micro-siting considerations can aid in selecting pre-construction strategies for projects.
Whereas additional research is needed to better establish the effectiveness of these strategies, the wind energy industry has continued to take a conservative approach with measures such as implementing setbacks and buffers around potential bat use areas.
Similarly, the types of biological information noted above can inform efforts to develop science-based siting policies.
There are 20 bat species that occur in Canada, and although it is not practicable to avoid siting wind energy facilities near features of importance to all of these species, pre-construction assessments of concentrating features like water bodies and forests can contribute to impact avoidance. Key strategies include siting and micro-siting to avoid important habitat features and designs that avoid the creation of attractant features.
Post-Construction Monitoring and Estimating Impacts to Bats
Post-construction monitoring, most commonly in the form of fatality monitoring, is an important component of impact assessment and adaptive management to minimize impacts of development. Post-construction fatality monitoring for wind energy facilities presents significant challenges due to the competing needs for precision and affordability.
Fatality monitoring typically consists of searches for bat fatalities beneath turbines at set intervals. Because bat carcasses may go undetected for a variety of reasons, leaving us with incomplete information or uncertainty regarding the actual number of fatalities, a statistical estimator is used to calculate an estimate of this value based on the number of fatalities detected.
There are multiple variables that can significantly affect final fatality estimates, and these should be considered when developing a post-construction monitoring plan. These variables include sampling protocols and designs, carcass persistence, searcher efficiency, effective sampling of the carcass distribution and the choice of estimator.
Operational Avoidance and Minimization
It is not possible to avoid all impacts to bats during the development of wind energy projects. Measures to avoid and minimize impacts during operations are, therefore, important tools for effective bat conservation. Avoidance and minimization refers to steps taken to prevent impacts of an activity or to minimize those impacts where it is not practicable to completely avoid them. Operational avoidance and minimization strategies are designed to reduce bat fatalities at operational wind energy facilities, and implementation of these strategies often takes into account a facility’s characteristics (e.g., turbine layout, wind speeds and proximity to bat concentration areas, such as bat hibernacula).
Operational avoidance can include general measures (e.g., timing restrictions on maintenance activities and avoidance of hibernacula); operational modifications, such as
turbine curtailment; deployment of risk-reduction technologies, such as bat deterrents; or a
combination of these measures.
Flexibility in approach is paramount to the success of these strategies. The early-stage development and testing of most technical measures currently available also offers an opportunity for the wind industry to participate in research to assess their effectiveness and identify conditions under which they are most effective.
Compensation and Offsets
When predicted or observed effects on bats cannot be avoided, it may be appropriate to compensate for these effects to reduce or eliminate the potential net impact. The emergence of WNS in North America has produced severe impacts to some bat populations in Canada; targeting mitigation of WNS is, therefore, a high priority for bat conservation. Wind energy developers and operators seeking methods to compensate for their much lower effects can perhaps have the greatest impact by working to reduce the impact of WNS.
Additional compensation options that can return conservation benefits to bats include habitat protection, habitat enhancement and conservation banking. Some options, such as habitat protection or enhancement and long-term forest management, are widely applicable and feasible, whereas others, like captive bat programs or reduction of WNS impacts, are more limited in scope or practicability. The applicability of a given compensation option and the best path to conservation benefit for a wind farm will likely depend upon the unique circumstances of the facility.
Adaptive Management Framework
The prediction and mitigation of potential impacts is imperfect, and it is, therefore, important to adaptively manage operations and monitoring activities as new information becomes available. Adaptive management refers to a structured, iterative process by which recurrent decisions are made based on information gained from the results of prior management actions. Adaptive management is most appropriate when there is baseline knowledge to inform predictions about the effects of management actions tied to a decision, but there is scientific uncertainty about those predicted outcomes.
In a wind industry context, adaptive management can occur at the project level, to inform and adjust ongoing management decisions, but perhaps more importantly at a broader scale, wherein information from multiple projects can inform policy, planning and standard practice over time; reduce uncertainty about wildlife populations potentially at risk; and help improve decisions at new projects.
A key benefit to taking an adaptive management approach is that the focus remains on maintaining sustainable bat populations in Canada. The approach thus allows for flexibility, accommodates consideration of a variety of measures and combinations of measures to optimize strategies for individual projects, reduces scientific uncertainty over time, and recognizes the role that clean energy plays in reducing threats from fossil fuel reliance and resultant climate change.
The review provides an assessment of the efficacy of various mitigation options to avoid, minimize or compensate for wind energy effects on bats, along with monitoring considerations, and an adaptive framework aimed at improving bat conservation efforts across Canada.
The full report can be found here.