Who Do We Have to Thank for Floating Solar Over Our Drinking Water?

By Karen Larson Henry, P.E.

September 21, 2024

Voice of San Diego reported earlier this year, ” San Diego Could Be First to Float Solar on Drinking Water.” This floating solar panels on Sweetwater Reservoir project continues to advance. The Sweetwater Authority has touted their innovative project for its renewable energy and annual cost savings potential. Yet, the agency appears unconcerned with the challenges that they would face by generating energy on their customers’ drinking water supply. They have yet to quantify the project’s downsides and the future costs for the ratepayers or concede that an Environmental Impact Report is warranted.

The Sweetwater Reservoir is a fenced off “restricted access” lake. Urban runoff is diverted away from that reservoir. These man-made barriers protect this drinking water supply in accordance with U.S. Environmental Protection Agency guidance. The proposed floating solar panel systems would be located inside those barriers. These systems have the potential to pollute the water by leaching compounds over time and proliferating illness-causing bacteria and viruses from roosting birds. Removal of contaminants from the water supply would be challenging and costly.

We have many people to thank for prioritizing renewable energy over protection of our drinking water supply.

1. Biden’s renewable energy goals. The current administration set ambitious goals: 1) to achieve 80 percent renewable energy generation by 2030 and 2) eliminate fossil fuels as a form of energy generation in the U.S. by 2035. Legislators seized this opportunity to advance floating solar technology. Congressman Paul Tonko D-NY, Congressman Jared Huffman D-CA, and Senator Angus King I-ME sponsored legislation, “Powering Our Nation’s Reservoirs.” The U.S. Department of Energy’s National Renewable Energy Laboratories (NREL) identified 24,000 man-made water bodies in the United States suitable for FPVs (floating photovoltaics.) This on line “Clean Energy Generation Capacity of Floating Solar on Reservoirs” tool identifies every reservoir and its energy generation capability. The prospect of federal funding makes this technology attractive to water agencies that serve disadvantaged communities. The City of Cohoes, New York (population 18,000) received $3 million in federal funding for their municipally owned and operated demonstration floating solar project to be installed on its water reservoir.

2. Local leaders at San Diego Community Power. San Diego Community Power supports renewable energy in all forms. Their website reads, “We contract for wind and solar power as part of our diversified power mix to ensure cleaner and reliable energy supply. We’re committed to entirely clean and renewable energy by 2035 or sooner.” National City Councilmember Ditas Yamane serves on the Sweetwater Authority Board and the San Diego Community Power Board. She wants to use the Sweetwater Reservoir to achieve local renewable energy goals. This collaborative floating solar vision for Sweetwater Reservoir would cover three quarters of the reservoir with solar panels. Director Yamane and Vice Chair Hector Martinez promoted this “supersize me” floating solar proposal during a recent Sacramento legislative trip.

3. Sweetwater Authority. The Sweetwater Authority is a publicly-owned water agency with policies and procedures established by a seven-member Board of Directors. The Governing Board is composed of five directors elected by division by the citizens of the South Bay Water (formerly the South Bay Irrigation District) and two directors appointed by the Mayor of National City, subject to City Council confirmation. The handful of individuals whose vote in June 2023 launched a floating solar panels on Sweetwater Reservoir project with a sole source contract are:

Chair Paulina Martinez-Perez, South Bay Water Division 2

Vice Chair Hector Martinez, South Bay Water Division 4

Director Steve Castaneda, South Bay Water Division 1

Director Manny Delgado (appointed) South Bay Water Division 3, and

Director Ditas Yamane, National City.

Chair Martinez-Perez made the motion; Director Delgado seconded.

As long as Sweetwater Authority hasn’t broken any laws, floating solar on Sweetwater Reservoir will likely be generating energy by 2026. The State regulators the Sweetwater Authority professes will make this project “safe” do not have the legal statutes to prohibit this renewable energy project even if they think it is a terrible idea rooted with problems.

So, barring a miracle… Save Sweetwater Reservoir may just be the impossible dream.

Coming to other water bodies near you: The City of Chula Vista’s Office of Sustainability included “evaluate floating solar” in their draft 2024 Climate Action Plan Update this summer. Yet, the City of Chula Vista does not own and operate any water bodies that could host floating solar panels. The Sustainability Commission and City Council will review the plan update for approval in early 2025. Mayor John McCann serves on the San Diego Community Power Board.

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