California prairie once proliferated across the Central Valley before it was converted to cropland. A new project involving solar power, pollinators, native plants, Native people, and even a salamander is shaping ways to help restore the ecosystem while also advancing clean energy. 

EPRI and the Sacramento Municipal Utility District (SMUD) launched the collaborative project this week to test the restoration of pollinator habitat on 20 acres of a decommissioned nuclear generating station near Sacramento. 

Researchers and students from the UC Davis Wild Energy Center will use the site as a testbed to evaluate the ideal native plant mix to grow beneath the site’s solar panels. They will assess the site’s habitat for pollinators and the federally protected California tiger salamander, characterize the soil properties and carbon sequestration potential, and co-develop with Indigenous tribes projects that help ensure both energy and socio-ecological benefits at the site. 

The 2,000-acre property is now home to the Cosumnes Power Plant, a utility-scale solar project, and a nature preserve.

“We’re trying to create a model that solar developers across the Central Valley can follow,” said UC Davis Associate Professor Rebecca R. Hernandez, Wild Energy Center director. “This is an opportunity to stack California prairie with solar energy and begin to restore the 98% of prairie habitat that’s been lost.”

Beyond renewable energy

The project serves to demonstrate how land restoration, renewable energy and environmental justice goals can work together to the benefit of people, pollinators, endangered species, biodiversity and clean energy. 

The project includes creating a pollinator habitat under established solar panels and measuring changes in energy, soil carbon, and management costs at the Rancho Seco restorative energy site. Restorative energy moves beyond renewable energy to help restore the ecological and cultural integrity of the land.  

For the project, the research team will consult and balance the needs of Native tribes, solar panel owners, state and federal wildlife agencies, neighboring landowners, resident shepherds, and the ongoing security needs of the retired nuclear power plant. The land is also occupied by the California Tiger Salamander and is home to the ancestral lands of the federally recognized United Auburn Indian Community. 

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“The Rancho Seco project is a unique collaboration at the intersection of communities, biodiversity, and climate-friendly energy,” said Jessica Fox, senior technical executive and conservation biologist at EPRI. “Successful demonstration could provide the blueprint for future renewable energy projects throughout the country that are restorative not just in their kilowatts, but also for local people and biodiversity.”

Nurturing Native seeds

UC Davis Ph.D. student Yudi LI developed a unique list of species to plant at the facility that would balance the energy-generation needs of solar developers with the need to protect the California tiger salamander, restore pollinator habitat and provide ecosystem services.

The first criteria is that the seed are native to the Central Valley. To prevent shading out solar panels, Li prioritized species shorter than 3.5 feet, as well as species that are shade-tolerant, drought-tolerant, fire-resistant and - importantly - commercially available so other solar developers can replicate the project. 

"Environmental conditions are site-specific, but we believe that after our study, we'll be able to generalize species with appropriate properties for other solar facilities in California and the U.S.," Li said, adding that working with local tribes is an important aspect of such projects. "Collaborating with tribal groups to identify and nurture culturally significant vegetation, harvest the seed and build up a naive seed industry would hugely benefit successful projects in the near future." 

Power in pollinators

SMUD is part of EPRI’s Power-In-Pollinators initiative. Launched in 2018, the initiative is the largest collaboration of power companies working to understand pollinators. 

“We are excited for this project to consider multiple levels of energy including solar power, the energy needs of the biological ecosystem, and the restoration of cultural energy for our communities,” said Kathleen Ave, SMUD’s senior climate and ecosystem strategist and co-Chair of the Power-In-Pollinators initiative. “We have the potential to educate more than 100,000 people annually, restore specialized pollinator habitat, support our tribal partners, and help meet our renewable energy goals.”

Additional partners for the four-year, multi-phase project include the Xerces Society for Invertebrate Conservation, D.E. Shaw Renewable Investments, and NovaSource Power.
 

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