A floating photovoltaic array recently installed at the Preserve Golf Club in Carmel, Calif., is expected to produce 460 kilowatts when it comes online. Photo by Jimmy Ferreira
When executives at the Preserve Golf Club in Carmel, Calif., began considering solar power as a way to offset much of their electricity needs, they were wary of how such a grid could fit into the course. and the surrounding 20,000-acre Santa Lucia Reserve.
A light bulb was lit when Forrest Arthur, chief operating officer and general manager of the Santa Lucia Preserve Community Services District, came upon an array of floating solar photovoltaic panels at a Northern California winery.
“We wanted to do floating solar,” says Kyle Butler, GCSAA Class A superintendent at The Preserve GC and a member of the association for 14 years. “There were two reasons. One is the field of view. We didn’t want to have a large network on the ground. More important is the control of evaporation.
Talk about a cake fix and eat it too. The club’s 1,178-panel, 460 kilowatt array is installed and ready to begin transforming sunlight into approximately 80% of the electricity for the course, toilet blocks and clubhouse. And unlike an unsightly ground network, they are nestled on one of the course’s lined retention basins. The benefits go beyond mere aesthetics. The panels cover about 70% of the acre-plus pond surface, and the shade they provide is expected to reduce the millions of gallons of water lost to evaporation each year.
“We see that as a problem,” says Butler, who factors in annual evaporative losses of about 20 percent from the five storage facilities on the course that collect 50 million gallons a year; the course supplements its water needs through wells connected to underground aquifers. “It’s a hole in our water cup, so to speak. Every year we look and say, ‘OK, the rainy season is over. How many do we have and how do the wells produce? Can we get our quota from the wells? If not, we have to make a decision at that time.
“We are losing so many millions of gallons of water just to evaporation, water that is so hard to capture. We need this water. We cannot store excess water, so it is crucial to save every drop we receive.
Enter the $1.2m solar solution that’s installed but hasn’t generated a single watt as the price awaits utility provider Pacific Gas & Electric’s upgrades to its infrastructure to handle the contribution considerable renewable energy to the electricity grid.
Floating solar power is not a new idea, but it seems to be growing in popularity, especially internationally. Besides the potential for reducing evaporative losses, it also has a few other potential benefits. Often, water-based panels tend to be cooler than their floor-mounted counterparts, and cooler panels are more efficient than hot panels. They also offer an alternative where surface mounting is limited, whether by the limited space offered by rooftops or, in the case of California wine country, where terroir is a tangible commodity. There, it does not make economic sense, for example, to sacrifice hectares of vineyard land to the interests of electrical sustainability.
Such was the case at Far Niente Winery in Napa Valley, which in 2008 installed what was billed as the world’s first non-experimental floating solar panel. The winery had felt that a two-acre set would meet its needs, but wanted to limit the reduction of its main real estate. The compromise resulted in nearly half of its 2,296 solar panels — 994, to be exact — being mounted on pontoons floating and anchored to the bottom of the estate’s pond.
According to the U.S. National Renewable Energy Laboratory, the global deployment of floating photovoltaics (FPV) has increased dramatically over the past decade, to about 2.6 gigawatts, or 2.6 billion watts, enough to power nearly 2 million homes. China hosts around 52% of the world’s FPV capacity. The United States, which had only two FPV projects before 2016, had more than 20 by 2020 – most at water treatment plants or flooded quarries – with a combined capacity of around 12 megawatts (12,000 kilowatts).
NREL has found that there is a premium associated with installing floating racks: the higher structural costs associated with floats and the anchoring system cause floating racks to cost more per watt generated than racks mounted on the ground. floor.
Another problem: keeping the panels clean. Butler says that once the system is online, the panels will need to be monitored, and as production drops they will need to be refreshed “to knock off the bird poop and dust.” Butler is studying a semi-autonomous system to handle this task.
While that would drive up the cost, in places like Far Niente, where the value of the land itself, or The Preserve, where its commitment to sustainability and low-impact human development, can outweigh the price, FPV may be a good fit.
Although potential impacts on wildlife, particularly fish and birds, have not been assessed, Butler is confident that The Preserve’s range will not disturb local flora or fauna.
“It’s a lined pond that we empty almost every year,” he says. “Fish and really all aquatic life are very minimal. Even the birds are very minimal. We are surrounded by a 20,000 acre nature reserve. There are so many bodies of water better suited for them.
Andrew Hartsock is CWM senior editor.