How Our Solar Energy Research Aims To Support Wildlife
A single pronghorn stands outside of a solar farm. Photo by Kevin Smith
“Are wildlife willing to use habitat next to solar development fencing? This study will help answer that question.”
- Michael Dax, Western Program Director
Over the past year, we’ve posted several blog updates on our WIRED project focused on understanding interactions between pronghorn and other wildlife with utility-scale solar energy (USSE) facilities. These updates have detailed various aspects of our work related to our use of GPS collars and trail cameras as well as investigating how the availability of water influences these interactions.
For this post, we’re zooming out to provide some big-picture context for our work and what we hope to learn, the tools we plan to develop, and the policies we believe can be improved.
For decades, environmental and clean-energy organizations have been pushing for the adoption of renewable energy sources like wind and solar to replace fossil fuels like oil, gas, and coal. For these advocates, this transition will result in benefits for the environment and our health, but as more and more states have enacted Renewable Portfolio or Clean Energy Standards, the reality of implementing this transition has come into better focus.
Putting aside the environmental or social concerns associated with mining for precious metals like lithium and cobalt, which are required for batteries and solar panels, the transition to renewable energy has presented other challenges for land managers. In the West, USSE facilities frequently exceed 1,000 acres, and because federal and local regulations require these facilities to be fenced, large wildlife, especially ungulates like pronghorn, elk, and deer, permanently lose access to these areas.
Coupled with the fact that this region is experiencing impacts from climate change like drought and rising temperatures, this loss of habitat can prove detrimental because, while the environmental benefits of any single solar facility results are negligible, the impacts for local wildlife can be very real.
With this context in mind, the goal of our research is to minimize the impacts of USSE facilities on wildlife through proper siting and develop mitigation strategies on the part of developers, land managers, and regulators.
Siting and Surveys
More than any other factor when considering whether a USSE facility may impact wildlife is how and where it is sited. Siting means where the facility sits on a landscape, its size, habitat features it occupies or is adjacent to, including vegetative communities, and how it’s configured.
Some facilities are simple squares or rectangles while others are more complex polygons composed of multiple arrays that are fenced independently. Naturally, developers must initially prioritize a different set of factors over ones directly relevant to wildlife such as land ownership, proximity to transmission lines, solar capacity, and slope when identifying new projects.
Developers are required to determine whether any federally threatened or endangered species are present, but for more common, state-managed species, like ungulates, the requirements vary and are much less stringent. If GPS location data or any similar dataset exists, it will usually be considered, but more often than not, that kind of high-precision data is limited and not widely available.
Developers typically commission an on-the-ground survey, and although the nature of these surveys vary, these kinds of assessments typically fail to capture much more than a single point in time and cannot document any larger patterns of use.
With this in mind, one goal of our project is to develop pre-siting survey methodologies that are both effective and cost-efficient. We recognize that not every solar project will be preceded by a multi-year wildlife study that includes GPS collaring, remote cameras, drones, and sign and visual surveys.
So, how do we replicate the accuracy of our data in a way that can be widely implemented?
Although we are just over a year into our fieldwork and have just under a year of collar data, we are already looking at ways that our noninvasive surveys can be paired to provide information comparable to that of collar data, especially in the context of understanding how a particular area is utilized by wildlife over the course of a year.
Beyond informing future survey methodologies, another goal is to understand how wildlife use areas around or between USSE facilities and panel arrays. Most large wildlife species are excluded from the facilities themselves due to fencing, but is there additional displacement beyond that immediate footprint, or are wildlife willing to utilize areas directly adjacent to the fencing?
USSE facilities are also frequently broken up to include separate arrays creating unfenced pathways or corridors in between the panels (like the map on the left below).
Examples of solar fencing surrounding two USSE developments in the Four Corners region, San Juan Solar and Eagle Shadow Mountain Solar. Graphics by Kevin Smith
What configurations maximize wildlife use of these pathways and how can they be configured to optimize their utility?
Lucky for us, the San Juan Solar facility, which is the focus of our main study area, includes 10 potential pathways that were the result of land-ownership patterns, roads, and topographical features that necessitated the facility to be broken up into distinct arrays. These pathways have different dimensions ranging from as short as 100 meters to as long as 1,000 meters, and as narrow as 30 meters and wide as 550 meters.
This variation gives us an opportunity to understand what factors drive wildlife’s use of these areas.
Our data is still preliminary, but we are already noticing patterns suggesting the quality of vegetation within these pathways is as significant a factor as their length or width.
Mitigation
In most instances, siting cannot solve every issue that a large development might cause for wildlife. In the mitigation hierarchy after ‘avoid’ and ‘minimize’ comes ‘remediate’ and ‘offset’. With this in mind, we have been using our data to understand the factors that dictate or hinder broader, more general patterns of use by wildlife in desert ecosystems.
The availability of water, presence of livestock fencing, and quality of vegetation have emerged as three common issues that affect wildlife movement in desert ecosystems. When thinking holistically about landscape-scale conservation and the impact caused by the loss of habitat resulting from a USSE facility, water, fences, and vegetation are features that can be manipulated to improve habitat quality and utilization and reduce fragmentation.
As we previously detailed, water can have a significant role in dictating how pronghorn and other wildlife use and move through an ecosystem. Already, wildlife rely on a series of natural and manmade water sources like cattle or stock tanks. If pre-siting surveys determine that a USSE facility is likely to cut off or hinder wildlife’s ability to access a valuable water source, developing new sources through ground pumping or water catchment systems could help mitigate some of the negative effects.
Livestock fencing, typically barbed wire or woven mesh, has also been documented as a major hindrance to wildlife movement. Pronghorn are especially affected as they tend to prefer going under fences rather than jumping over them and do so more easily when the bottom wire is 16” or higher from the ground. Across the West, land and wildlife managers are retrofitting existing fences to be wildlife-friendly by raising bottom wires, lowering top wires, and, where possible, replacing barbed wire with smooth wire.
Finally, data from last summer showed that a green-up of vegetation following the summer monsoon season enticed wildlife to occupy areas immediately adjacent to the San Juan Solar facility that they had previously avoided. Where possible, strategically located vegetative treatments to seed native species that are valuable for wildlife can help offset areas they’ve lost access to and encourage wildlife to move into new areas that previously had little value.
While these solutions might not be applicable in every instance, they are common issues impacting wildlife in the West that can be addressed in a cost-effective manner with outsized benefits for wildlife and landscapes they call home.
Cumulative Effects
One of the trickiest issues surrounding solar and wildlife interactions to understand and unpack is the impact of cumulative effects.
While impacts to wildlife from one USSE facility can be more easily mitigated, what about two or three or even four?
Because access to transmission lines is often the largest driving force in siting projects, multiple facilities may be built in close proximity to each other. Compounding this, much of the West is checkerboarded between federal, state, tribal, and private land, and the different regulatory bodies and permitting processes aren’t required to consider what’s happening on neighboring lands.
Our study area includes lands owned and managed by the Bureau of Land Management, New Mexico State Land Office, Navajo Nation, and Ute Mountain Ute, not to mention four states and numerous private landowners.
So, what happens when a resident or migratory herd is excluded from as much as eight or ten thousand acres of habitat? Is there a tipping point at which we will begin to see population-level effects? Currently, there is just one existing USSE facility in our study area, but at least three more are currently being permitted, which will eventually offer an opportunity for us to examine this question in more depth.
Largely, this question will be one for policymakers, but in addition to any regulatory solutions, it will necessitate urgency around both siting and mitigation strategies we are already identifying.
When it comes to large-scale infrastructure development, we don’t have the best track record of getting it right the first time (environmentally speaking). Our wildlife and native ecosystems are already bearing the brunt of climate change, making them that much more fragile and susceptible to future disturbances. As we transition to renewable energy, we must take every precaution not to trade climate impacts for impacts to habitat if we want a future that is truly sustainable.
Cover photo by Kevin Smith.
