Utility-scale solar farms bloom in California desert

Palm Springs represents a dense area of solar development in North America. But the ability to meet ambitious renewable energy goals depends on a very limited water supply. Operating solar farms doesn’t require much water. However, environmental law requires developers to mitigate dust during construction. “Importing” water from elsewhere is costly. So developers rely on local groundwater.

The wells are the only fresh water source for Desert Center residents. Local communities claim solar projects built on public land, and overseen by the U.S. Department of Interior’s Bureau of Land Management (BLM), are depleting their water supply. Limited data exist about the Chuckwalla Valley Groundwater Basin. Studies suggest significant overdraft compared to the rate of aquifer recharge.

“The federal agency knew construction could impact local wells and may even be over-drafting the aquifer beneath them, according to former BLM staff, studies on the basin and public documents from the agency’s environmental assessments of the projects,” writes journalist Wyatt Myskow.

What happens if groundwater use by solar companies dries up local wells? The BLM requires developers to “reduce pumping until the aquifer returns to levels that allow wells to resume operations and cover the expenses for replacing equipment and wells.” Local groundwater well owners report receiving no help.

The BLM’s 2012 Western Solar Plan labeled 298,321 acres of public lands as “solar energy zones,” perfect for developing the renewable energy. Nearly half the zones are in the same zone as Desert Center. About 20,000 acres have been developed in the Palm Springs zone. Another 120,000 acres are available for solar development. BLM is now reviewing the clean energy economy acceleration plan.

The BLM reported enough groundwater for the most recently approved projects from Intersect Power and Clearway Energy Group. The evaluation was based on its environmental assessments of the proposed developments. The agency also found data were limited. It acknowledge the basin could already be overdrawn. Even if groundwater wasn’t being overused, the project “may adversely affect operation of nearby wells,” the assessment stated. A different solar project proposed by Intersect Power would require another 1,000 acre-feet of water during two years of construction. A third development proposal would need water. Developers have not estimated the amount.

Water assessments for each recently approved project estimated aquifer recharge, from rain, could range from 206 to over 20,000 acre-feet a year.

Under the Sustainable Groundwater Management Act (SGMA), groundwater sustainability agencies regulate and restrict groundwater use to avoid long-term issues in high-priority over-drafted basins. The Chuckwalla Valley Groundwater Basin is designated as a low-priority basin. Efforts to more accurately measure and avoid excessive extraction are yet to occur.

California state law doesn’t apply to federal lands, where most utility-scale solar projects are being built. Myskow reports the BLM has not answer questions about groundwater overdraft mitigation measures. Additionally, questions remain unanswered about any investigation of wells going dry, monitoring the Chuckwalla basin, or working with local communities. Under baseline conditions, the BLM found the basin would have a surplus of 2,390 acre-feet. But the lack of data makes “performing a detailed analysis” challenging. The water supply assessment found the aquifer could already be overdrawn by 6,685 acre-feet of water under lower precipitation and water inflow conditions.

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