Somewhere there must exist a great ecological ledger, administered by Bob Cratchit-like accountants who toll up the pluses and minuses of our fumbling human endeavours. One critical entry relates to the need to reduce our greenhouse gas emissions to prevent the world from overheating. There is no question we need to transition from fossil fuels to alternate energy sources.
Climate change, the big shift in our world, is a global risk to wildlife and their habitats. Increasing heat is a key factor in declines of the once common bumble bee, one of our essential plant pollinators. Reduced and warmer stream flows impact native trout. It’s hard to find a species in Alberta not affected by climate change. But we shouldn’t be blind to the issues renewable energy solutions can cause to wildlife and their habitats. When one considers habitat issues, wildlife mortality, and embedded energy costs for infrastructure, I’m not sure we should call these solutions “green.”
The Dark Side of Solar and Wind
Solar and wind developments are undergoing an exponential expansion, a literal energy gold rush, due to the urgency of the climate crisis and government subsidies designed to hasten the rollout of solutions. As befits a relatively new industry, assessing the ecological effects of renewable energy developments is beset by data deficiencies, lack of long-term monitoring, inadequate baselines, differing infrastructure types, and variable geographic and landscape differences. All of this confounds simple answers and solutions.
Both solar and wind facilities have footprints and operations that affect wildlife in a variety of ways. There are direct and indirect effects as well as cumulative effects, given that these facilities do not exist in isolation from other land uses.
It is well established that wind turbines kill bats and birds through collisions with vanes.1 In addition, mortality can sometimes occur through barotrauma, a huge pressure differential that causes internal haemorrhaging. The majority of deaths occur during migration and initially the concern was over birds, especially raptors and songbirds. However, as Jason Unruh, the provincial wildlife biologist who reviews renewable energy projects, says: “What was once a bird issue has become a bat issue.”
Bat populations are hard to estimate — many species are migratory, all are nocturnal, and most are solitary. Nevertheless, precipitous declines in most populations have been noted. Most biologists agree that impacts from wind turbines are a serious concern at the population level. This may have significant ecological implications because bats perform vital roles in pest control and pollination, essential to ecosystem function as well as our economy. If you think mosquitoes are a summer plague now, imagine a world of bug bites without bats.
Less information is available on direct wildlife mortality from solar facilities, not because it doesn’t occur, but because little research and monitoring has been undertaken with such a new development. There is a theory that solar panels apparently can resemble bodies of water (a lake effect) and lure birds like grebes and loons to their deaths. There is no post-construction monitoring or peer-reviewed evidence for this. An emerging issue is that, in prairie landscapes, human infrastructure, including solar installations, may provide elevated perches for owls and other predators, thereby altering natural predator-prey relationships.
Renewable energy projects also have indirect effects on wildlife. A recent study of the effects of wind turbines on whooping crane migration showed migratory habitat is reduced by wind energy development.2 For most migrating birds, rest stops and feeding areas serve as important stepping stones. Researchers found that whooping cranes avoided wind turbines to a distance of five kilometres. This effectively reduced habitats essential for migration, making some potential stopover areas unusable.
A study of the effects of solar developments on antelope in Wyoming found direct habitat losses of summer and winter ranges. Impervious fencing altered both seasonal and annual migration patterns and fragmented habitats. Joel Nicholson, the senior wildlife biologist in Alberta’s grasslands, points out there are biological issues associated with movement barriers, including extra energy costs that can increase antelope mortality in winter situations.
Species are already faced with significant cumulative challenges, including continued habitat losses, powerline and window collisions, illegal shooting, movement barriers, and other mortality factors. Those with small and declining populations may not be able to tolerate additional risk from wind and solar developments.
What Can Be Done
There are no “silver bullet” solutions, but one obvious step is to avoid placing infrastructure in high-risk areas. While this sounds simple, there are complexities that make this very difficult to implement. To assess risk there needs to be sufficient baseline information on basic biological questions of wildlife presence, numbers, distribution, movement patterns, and timing of movement. We also need to determine how wildlife species interact with different types of renewable energy infrastructure.
None of this can be accomplished effectively in the narrow development time frames of an industry in a rush. Areas of risk to wildlife are often identified after a development has occurred and significant mortality is observed. This is management by rear-view mirror; we develop insights from post-development monitoring and then apply them to new proposals elsewhere.
As an example of the complexity of the problem, one only needs to consider bats. Migratory bats (hoary, silver-haired, and eastern red) take the biggest hit from wind infrastructure, making up 90 per cent of bat mortality. Most of the deaths happen during the fall migration in August and September but, as bat researchers point out, “understanding of bat migratory behaviour is extremely limited.” Most of what we know about migratory pathways is gleaned from deaths at existing wind towers.1 An equivalent would be trying to assess wildlife populations by way of the extent of roadkill on highways.
Dr. Robert Barclay, an expert in bat research from University of Calgary, and several of his colleagues have investigated ways of potentially reducing mortality. For bats, understanding the temporal and spatial windows through which they fly can provide insight for mitigation strategies. As wind towers become taller, the vanes reach into the airspace used by bats. Consequently, minimizing tower height can reduce mortality. Recognizing that bats are nocturnal, undergo seasonal movements, and fly at low wind speeds gives operators the opportunity to curtail turbine use at night, at certain times of the year, and at times when winds are light.
Other wildlife mitigative strategies include ensuring unrestricted travel avenues exist, considering both physical access and avoidance behavior related to noise and human activity. Also, greater scrutiny is required of the changes in habitat conditions that arise from renewable infrastructure and associated roads and transmission lines. Siting these facilities on non-native landscapes and brownfields, and avoiding important connected wildlife habitat, would mitigate some of the negative effects.
Because of a lack of monitoring and research on management practices, mitigation efforts currently have variable success rates and are very much site specific. It remains unclear what the best strategies are. As the renewable energy footprint expands, the need to better understand, manage, and mitigate is clearly evident.
The intended scale of some solar facilities will be of concern from a wildlife perspective. Plans for solar “farms” of 5,000, 9,000 and even 16,000 acres of enclosed, wildlife-impermeable fenced space will reduce habitat availability and pose serious movement issues for virtually all wildlife species larger than ground squirrels and mice. There could be the unintended consequence of losing more native grassland. Renewable energy companies, who tout themselves as “green,” need to show they are willing to forgo some economic opportunity in favour of obtaining social license for their developments by minimizing wildlife impacts.
Before things get completely out of control, as was the case with past oil and gas development, it would be useful to undertake regional-scale cumulative effects assessments, which could help define the siting requirements and also set appropriate limits on development. Government has a role to guide development through a combination of carrots and sticks. A first step might be to encourage the development of solar facilities in urban areas, with panels arrayed on the roofs of houses and office, retail, factory, warehouse, and government buildings.
As a biologist I worry about the effects of climate change on wildlife. I’m also concerned about how our technological solutions involve trade-offs with no clear picture in sight for the persistence of wildlife. In the shift to renewable energy to limit greenhouse gas emissions, we risk running over wildlife, converting wildlife populations to red ink in the ecological accounts, as we attempt to keep up with our high energy demands.
Yes, we need these low-carbon energy developments to combat climate change, but we have to be smart about facility development. There inevitably will be trade-offs between energy development, land availability and suitability, human constraints, and conservation goals. There will be conflicts resulting in winners and losers. In a perfect system, human and environmental constraints would limit locations to where renewables are compatible. But if designs and development criteria don’t incorporate steps to limit, minimize, or mitigate negative effects, wildlife will lose.
Lorne Fitch is a Professional Biologist, a retired provincial Fish and Wildlife Biologist, and a former Adjunct Professor with the University of Calgary.
This article originally ran in Nature Alberta Magazine – Summer 2023.