Solar power is booming. But it’s putting desert wilderness at risk.

How renewable energy projects in the Mojave Desert threaten local species — and how to fix that.

The Mojave Desert, straddling California and Nevada, has been called the Saudi Arabia of solar power. It’s a clean energy developer’s dream: vast open lands, roughly equal in size to the entire state of New Mexico, with an endless bounty of heat from the sun. 

Hundreds of thousands of acres of federal land in the Mojave have been made available for solar plants, and applications have been pouring in over the last few years from the likes of Goldman Sachs, California utility giant Pacific Gas & Electric and multiple Silicon Valley-backed startups.

But as developers scramble to set up their projects, some scientists and conservationists are warning us not to forget vital ecosystems in the process. What about the threatened cacti and the ants that rely on their nectar? they ask. Or the birds that nest in tree-like Mojave yucca, a cousin of the iconic Joshua tree? Striking a balance between conservation and renewable energy, experts say, is critical for a sustainable future.

Solar development can reduce or alter local biodiversity, according to a new study published in July in the journal Nature Sustainability. But there are ways to avoid or limit the damage. These include creative design to protect threatened plants and less-intense methods for clearing the land before construction. Better yet, say the researchers, efforts should first be made to choose sites that have less environmental significance, like the roof of an already existing warehouse or an abandoned mineral mine. 

“Renewable energy is the future, we need it, that’s obvious,” said Steven Grodsky, an assistant research ecologist at the University of California, Davis and co-author of the paper. The question he said is, “How can we do this in the smartest, most sustainable way possible?”

To help answer this, Grodsky and co-author Rebecca R. Hernandez, an assistant professor at UC Davis’ Department of Land, Air and Water Resources, measured the impact of California’s 392-megawatt-capacity solar plant on the desert ecosystem in Ivanpah Valley, which sits just outside the Mojave National Preserve along the Nevada border. 

The 3,500-acre Ivanpah installation ― roughly the size of Los Angeles International airport ― is one of the world’s largest concentrating solar power plants, using vast arrays of mirrors to direct sunlight to a central generator. 

Owned by Oakland, California, startup BrightSource Energy with key investors including Google and NRG Energy, the project was proposed in 2007, but didn’t begin construction until 2010 after years of controversy surrounding its potential impact on desert wildlife. Construction plans had to be revised to minimize ecological damage. 

One of the biggest concerns was how to protect endangered desert tortoises, which were ultimately relocated from the site prior to construction.

Developers also had to make sure they avoided certain areas with the rarest plants, including cacti and yucca. These iconic desert species can live for hundreds of years and provide vital ecosystem services to other species. They also hold cultural significance for the communities that rely on them. Sometimes the plants struggle to grow back after being cut down to make way for the installation of solar panels. What’s more, the invasive grasses that set up home in their place can contribute to wildfires, which damage or kill the native plants.

The most common way of developing land for a solar project is what the industry calls “blading” ― essentially bulldozing to clear and flatten the land in preparation for installation. Blading removes all above-ground vegetation as well as soil and roots about a foot deep. And, according to the study, the process encourages the growth of invasive grasses.

In other words, Grodsky said, “Blading is going to make deserts the barren wasteland that people think deserts are.”

The other way to prepare the land is called “mowing.” It’s less intensive ― all plants shorter than a foot remain and no soil is removed. While the tall cacti and yucca still don’t fare well, this technique does give some native desert shrub species a greater chance to grow back. 

While parts of the Ivanpah facility were bladed, mowing was done in the outer areas. At the time it was built, this “was super novel,” said Grodsky. “It was one of the first times [mowing’s] ever been done.”

The solar plant also roped off several little islands among the mirrors where no blading or mowing was done to protect rare plant species. 

For their study, Grodsky and Hernandez examined the plant ecosystem seven years after the land had been cleared for the solar installation. The environment looked pretty “sparse,” Grodsky said. Over the seven years, invasive grasses had grown around the panels and some native shrubs had come back successfully. The cacti and yucca, however, weren’t so lucky.

Where they were cut down, the cacti and yucca failed to rebound. In the roped-off areas, however, they were found in similar amounts and sizes to what existed outside the facility. This shows that growing near solar panels didn’t disturb these plants, said Grodsky, and highlights the potential to design facilities that work around critical species rather than digging or cutting them up.

With their findings, Grodsky and Hernandez hope to provide recommendations to make solar development in the Mojave Desert less harmful to the local environment.

Balancing the need to address climate change with the support of vital biodiversity is one of the biggest conservation challenges of our time, said John Zablocki, Southern Nevada conservation director for the Nature Conservancy. “It is an absolute imperative to tackle the threat of climate change,” he said, but “in the process, we don’t want to lose or accelerate the loss of the very things that we’re trying to protect from climate change in the first place.”

It’s an issue California is currently struggling with as solar and wind developers try to stop a petition that seeks endangered species protection for Joshua trees, which they argue will hinder new installations.

Calling deserts “our last places of wilderness,” Hernandez said, “They have these expansive open areas that intrinsically make them really vulnerable to development. There’s this ideology that deserts need to be developed to make them useful to society.”

Ideally, she said, less pristine locations should be developed first: “Let’s build solar in the places that are already adversely impacted, that we’ve already screwed up, that have low environmental value.”

This could mean everything from putting solar panels on the roofs of homes, parking garages and large commercial buildings to constructing a utility-scale floating solar project in a giant reservoir. Then there are what’s called “marginalized lands,” places like landfills, mines and contaminated brownfield sites, which many are eyeing as the perfect spots for renewable energy projects. 

The challenge, though, is that it’s been technically simpler to build on undeveloped land. “If you buy a plot of forest and cut it down and level it and then build a solar project on top of it,” said Zablocki, “that’s easier to do than doing that same thing on a piece of land that’s had some other prior economic use. Kind of like a clean slate, so to speak, there’s just fewer complications.”

Building on previously developed land can be riskier, between the costs of dealing with abandoned infrastructure and possible contamination and the need to navigate a host of regulations related to all that. 

To lower some of these barriers, the Nature Conservancy has over the past few years been working to open old mine sites in Nevada ― one of the nation’s top hard rock mining states ― to solar power development.

The Environmental Protection Agency estimates there are 43 million acres of brownfields and mine lands across the country that are technically feasible for renewable energy development. Nevada itself has roughly 2.8 million acres of former mine sites. “There’s a huge potential there,” said Zablocki, “and we haven’t even made a dent in it.”

“If we can put somebody on the moon, we can figure out how to retrofit a mined site to produce and store renewable energy,” he said.

In 2018, the Nature Conservancy persuaded Nevada to update its state mine reclamation rules ― which detail how the land must be restored after mining is finished ― to include renewable energy development and storage as acceptable post-mining uses.

The organization is now working on a pilot project to demonstrate the potential of converting old mine sites to clean energy and is partnering with other environmental groups to promote the idea, which is already gaining steam in West Virginia, Colorado and Wyoming, according to Zablocki.

He sees enormous promise in turning “these large industrialized areas of the past and present” into “the clean energy hubs of the future.” 

“There’s something fundamentally hopeful about that thought,” Zablocki said. “It’s something we can do.”

Environmental concern obviously didn’t play a big part during the first wave of energy development ― the extraction of fossil fuels ― Grodsky said. But that can change now. “It’s almost like we have a second chance,” he said, “to implement this new wave of renewable energy development in a way that’s sustainable.”