Float-o-voltaics ready to power California club

The Preserve Golf Club in Carmel, Calif., created a "floating solar" solution to electricity offset.


floating solar photovoltaic system
A recently installed floating photovoltaic array at The Preserve Golf Club in Carmel, Calif., is expected to produce 460 kilowatts as soon as it goes online. Photo by Jimmy Ferreira

When the powers-that-be at The Preserve Golf Club in Carmel, Calif., started looking into solar as a way to offset much of their electricity needs, they were wary about how such a large array would fit in at the course and the surrounding 20,000-acre Santa Lucia Preserve.

A lightbulb lit when Forrest Arthur, chief operating officer and general manager of the Santa Lucia Preserve Community Services District, happened upon a floating photovoltaic solar-panel array at a winery in Northern California.

“We wanted to do floating solar,” says Kyle Butler, GCSAA Class A superintendent at The Preserve GC and 14-year association member. “There were two reasons. One is the viewshed. We didn’t want to have a large on-ground array out. More important is evaporation control.”

Talk about a cake-and-eat-it-too solution. The club’s 1,178-panel, 460-kilowatt array is installed and ready to start turning sunlight into roughly 80% of the electricity for the course, comfort stations and clubhouse. And unlike an unsightly ground array, they’re tucked away on one of the course’s lined retention ponds. The benefits of that go beyond simple aesthetics. The panels cover roughly 70% of the surface area of the acre-plus pond, and the shade they produce should reduce the millions of gallons of water lost yearly to evaporation.

“We definitely look at it as a problem,” says Butler, who factors in yearly evaporation losses of roughly 20% from the course’s five storage facilities that collect 50 million gallons per year; the course supplements its water needs with wells connected to underground aquifers. “It’s a hole in our cup of water, so to speak. Every year, we look and say, ‘OK, the rainy season is over. How much do we have, and how are the wells producing? Can we get our quota from the wells?’ If not, then we have to make a decision at that point.

“We’re losing so many millions of gallons of water just to evaporation, water that’s so hard to capture. We need that water. We can’t store a surplus of water, so it’s crucial to keep every drop we get.”

Enter the $1.2-million solar solution that is installed but hasn’t generated even one measly watt as the course awaits upgrades from utility provider Pacific Gas & Electric to its infrastructure to be able to handle the considerable renewable contribution to the power grid.

Floating solar isn’t a new idea, but it seems to be gaining in popularity, especially internationally. Besides the potential for reducing evaporation losses, it has a few other potential benefits as well. Frequently, waterborne arrays tend to be cooler than their ground-mounted counterparts, and cooler panels are more efficient than warm ones. They also offer an alternative where surface mounting is limited, whether by the finite space afforded by rooftops or, in the case of California wine country, where terroir is a tangible commodity. There, it’s not economically sensible to, say, sacrifice acres of grape-growing ground to the interests of electric sustainability.

Such was the case at the Far Niente Winery in Napa Valley, which in 2008 installed what was billed as the world’s first nonexperimental floating solar array. The winery had estimated a two-acre array would meet its needs but wanted to limit the reduction of its prime real estate. The compromise resulted in nearly half of its 2,296 solar panels — 994, to be exact — mounted on pontoons floating in and anchored to the bottom of the estate’s pond.

According to the U.S. National Renewable Energy Laboratory, global floating photovoltaic (FPV) deployment has increased substantially in the past decade, up to about 2.6 gigawatts — that’s 2.6 billion watts, or enough to power nearly 2 million homes. China hosts about 52% of global FPV capacity. The U.S., which had only two FPV projects before 2016, had more than 20 by 2020 — most on water treatment plants or flooded quarries — with a combined capacity of roughly 12 megawatts (that’s 12,000 kilowatts).

The NREL has found there’s a premium associated with the installation of floating arrays: Higher structural costs related to the floats and anchoring system make floating arrays costs more per watt generated than ground-mounted arrays.

Another issue: keeping the panels clean. Butler says once the system goes online, the panels will need to need to be monitored, and as production drops, they’ll needed to be spruced up “to knock the bird poop and dust off.” Butler is looking into a semi-autonomous system to handle that task.

Though that would add to the cost, at places like Far Niente, where the value of the ground itself, or The Preserve, where its commitment to sustainability and low-impact human development, can take precedent over price, FPV can be a good fit.

Though potential impacts to wildlife, particularly fish and birds, haven’t been assessed, Butler is confident The Preserve’s array won’t upset local flora or fauna.

“It’s a lined pond that we nearly drain every year,” he says. “Fish and, really, any aquatic life is very minimal. Even birds are very minimal. We’re surrounded by a 20,000-acre nature preserve. There are so many bodies of water better suited for them.”

Andrew Hartsock is GCM’s senior managing editor.