Solar energy faces a conundrum: Sunshine is free, but land is not. In cities, solar panels often are mounted on buildings to make the most efficient use of real estate, but what are pricey rural areas, such as California’s wine country, supposed to do?
“Floatovoltaics” are a new concept here in the United States, but the idea has gained traction in a few other countries. Since 2007, nearly 100 megawatts of floating solar installations have been built, almost entirely in Japan, China, Korea, and the United Kingdom. The largest U.S. installation is at Far Niente Winery in Napa Valley, pumping out 175 kilowatts. With only six floating solar installations in the United States as of 2017, there appears to be a tremendous opportunity for growth in this niche solar market.
In 2016, Kunde Family Winery in Sonoma Valley decided to pilot the concept too. By adding 10 kilowatts of photovoltaic panels to one of the winery’s eight irrigation ponds, the winemakers could leverage solar energy, while preserving precious soil for the vineyards—a wise move considering the land for their wine’s terroir costs up to $150,000 per acre.
As the California wine industry begins to explore the novel application of floating photovoltaics, could others benefit from the same approach? This is the question a team of Stanford undergraduates set out to investigate last summer through support from the TomKat Center for Sustainable Energy.
“When I saw the project, I jumped at the chance to do this,” says Mfon Ikebwe, ’19, who is studying civil and environmental engineering. She was among six students who received Energy Impact Fellowships from the TomKat Center and the Haas Center for Public Service.
“Not only did I have the opportunity to learn from influential people who work with water and sanitation, but those who are powerful in the energy field,” she says.
The team spent June through August interviewing key stakeholders in the emerging field, including photovoltaic manufacturers, water districts and agencies like the Sonoma County Water District and the U.S. Bureau of Reclamation, cities such as San Diego and Santa Rosa, and the National Renewable Energy Laboratory.
The Stanford undergraduates developed a clear picture of the market potential for floating solar by the end of the summer. Their findings suggest that California's floating solar capacity could be a whopping 20 gigawatts. The best candidates for the new technology are at locations that already have an abundance of water, such as water treatment plants, reservoirs, and even industrial plants, or businesses where profit is tied to land productivity, such as wineries and farms. The team’s full report is available here.
“I hope that our research will be used to help inform state-level policy that makes the floating solar permitting process faster,” says Dylan Sarkisian, ’17, MS ’18. “It may take a few years, but I think our final report and case studies will serve as a helpful starting point for policy analysts.”
Like ground-mounted solar, Sarkisian explains that floating solar needs attention and recognition as a viable energy option in order for regulators to start streamlining the permitting process. He hopes the report will elevate other benefits of the floating panels too, such as the ease of cleaning them (dip a mop in the pond and voilé!) and increased panel efficiency, as well as reduced evaporation and algae growth in ponds. Given that the state of California intends to generate half of its electrical power from renewables by 2030, the Stanford students anticipate that floatovoltaics will become part of the energy puzzle.
Essential to that will be education; they heard over and over again from experts that the lack of awareness and knowledge about this technology will be its greatest hurdle.
For the six Energy Impact Fellows, it was a summer of learning and growth.
“The most challenging part of the fellowship was actually learning how to construct my own workday because I’m a very scheduled person during the school year. In the end, I really grew to like the freedom I had to call all the shots in my day,” says Ikebwe.
Emily Miller, ’20, shared similar thoughts: “The most valuable thing I learned about was working in groups with little supervision.”
The TomKat Center provided the framework, timelines and goals for the project and introduced the students to key stakeholders but gave them the flexibility to shape the project based on their own ideas and strategic decisions. Each Monday, the fellows gathered with their mentor Brian Bartholomeusz, executive director of innovation transfer at the TomKat Center, in a conference room in the Shriram Center and began the task of charting their course for the week. Throughout the week they reached out to experts in the field by phone or email and conducted other research, including site visits. The group met again later in the week to evaluate progress made toward the week’s objectives and to set the stage for the next Monday planning meeting.
“To me what is most striking is how confidently and competently the students take over handling interviews and discussions with the internal and external experts we enlist,” says Bartholomeusz, “This growth is what learning should be about.”
Learn more about the Energy Impact Fellowship.