»Ê¹ÚÌåÓýappÏÂÔØ

Introduction

Image Details

As communities realize long-term dependence on fossil fuels for power generation is not sustainable due to limited coal, natural gas, and oil availability, alternate methods of energy development, including solar, are expanding across the globe. Alternative energy also reduces carbon emissions that contribute to climate change climate change
Climate change includes both global warming driven by human-induced emissions of greenhouse gases and the resulting large-scale shifts in weather patterns. Though there have been previous periods of climatic change, since the mid-20th century humans have had an unprecedented impact on Earth's climate system and caused change on a global scale.

Learn more about climate change . Although these power generation techniques do not have the environmental and human health impacts of fossil fuel-based generation, they are not without negative impacts. Large-scale solar facilities can severely degrade ecosystem condition and the wildlife they support when they are built on previously undisturbed land that is biologically fragile. To explore options for minimizing these impacts, Valley Electric Association (VEA) and US Fish and Wildlife Service worked together to construct a wildlife-friendly solar power generation facility in the Mojave Desert near Pahrump, Nevada.

Key Issues Addressed

The southwestern United States is important for solar development because of its ample solar energy and open land. However, undisturbed lands are home to many species that depend on large, unfragmented landscapes. Large-scale solar construction, including vegetation clearing and grading, directly disturbs habitat on an increasing scale as the number and size of facilities expand. Equipment and infrastructure can also cause direct wildlife mortality. Fence barriers around facilities cause habitat and migratory corridor fragmentation. Wildlife species particularly affected include the desert tortoise, desert bighorn sheep, and the Mohave ground squirrel. Solar panel arrays can also create an optical illusion of water, potentially attracting water birds that are unable to take off on dry land.

Project Goals

• Implement a pilot project to incorporate wildlife-friendly features into solar facilities to minimize negative effects on wildlife and their habitats while meeting growing demands for renewable energy
• Monitor the use of the site by wildlife, particularly the Mojave desert tortoise 

Project Highlights

Power-Generating Habitat: Modifying development protocols can provide energy for the public while maintaining functional habitat for wildlife.

• Innovative Solar Panel Placement: To maintain existing plants and natural topography, VEA only clipped vegetation as necessary instead of clearing the area to place solar panels. To allow space for vegetation undergrowth, the lower side of solar panels was set at 42 inches above the ground, 18 inches above the industry standard of 24 inches. The spatial arrangements of panels was intentionally varied and increased spacing from 14 feet to 20 feet to minimize the illusion of a lake and allow more light to reach the ground.
• Maintaining Habitat Connectivity: Openings of 10 inches wide by 7 inches tall were placed approximately every 260 feet along the perimeter fence (a total of 30 openings) to allow wildlife passage.
• Reducing Vehicle Impacts: Maintenance vehicles were restricted to small utility vehicles with a maximum speed of 15 miles per hour. Staff also received desert tortoise awareness training.
• Temporary Tortoise Relocation: Before construction of the site started, biologists moved desert tortoises from the project area to temporary holding pens. Prior to release, four of these tortoises were fitted with radio transmitters to monitor passage and long-term residency.
• Benefits of Partnership: »Ê¹ÚÌåÓýappÏÂÔØ with VEA allowed FWS to use the site as a pilot project where they were able to collect data and information about impacts, mitigation strategies, and desert tortoises.

Lessons Learned

Image Details

The relatively small footprint of this project allowed experimental implementation to assess how solar power generation facilities can be designed to reduce impacts to wildlife. Tortoises were documented passing through the facility during the warm months, indicating that fence openings were effective. Rattlesnakes, black-tailed jackrabbits, and kit foxes also used fence openings. Elevated placement of solar panels allowed extensive vegetation to persist at the site, although it was initially trampled during construction. Active re-vegetation and control of invasive weeds are recommended to enhance vegetation conditions after construction.

Energy developers may express initial caution to new technologies that might decrease the quantity of solar panels needed to fulfill energy needs. They may anticipate that alternative development options such as raised solar panel placement will be too expensive or difficult to build. Improving where and how to develop alternative energy sources will be an iterative, collaborative process, where concerns of both developers and environmental interests must be actively addressed. 

Mitigation techniques need to be tested at larger solar facilities to determine the degree to which habitat quality can be maintained. Even at the small scale of this site, mitigation techniques did not eliminate wildlife impacts. Some proposed generation facilities may impact 200+ tortoises instead of the handful of tortoises at the Pahrump project site. 

The wildlife impact mitigation options used at this site do not eliminate impacts to wildlife and their habitats. Placing solar power generation facilities away from places with high conservation value remains the best way to minimize wildlife impacts. This can include prioritizing placement of solar power generation facilities where there is existing infrastructure, near urban areas, or in retired agricultural lands. 

Next Steps

• Monitor for bird attraction and mortality from the solar panel “lake effectâ€�
• Prioritize lands with lower conservation value for solar power generation, such as previously disturbed land and land near urban areas
• Explore options for constructing solar power facilities in retired agricultural areas
• Use project results to promote incorporation of these practices in other solar developments 

Resources

• Jennifer Wilkening and Kurt Rautenstrauch, 2019. “Can Solar Farms Be Wildlife Friendly?â€� A summary article in .. 
• US Fish and Wildlife Service, Pacific Southwest Region

Contacts

• Jennifer Wilkening, Wildlife Biologist and Habitat Conservation Planning Coordinator, US Fish and Wildlife Service, [email protected]
• Roy Averill-Murray, Desert Tortoise Recovery Coordinator, US Fish and Wildlife Service, [email protected]
• Mark Duvall, Supervisor of Lands and GIS, , [email protected]

Case Study Lead Author

Sierra Riker, CART Intern, Northern Arizona University

Suggested Citation

Riker, S. (2019). “Wildlife-Friendly Solar Energy in the Mojave Desert.â€� CART. Retrieved from /project/wildlife-friendly-solar-energy.