Tommy O'Neal revs his all-terrain vehicle up and down the bumps of this moonscape in southern Polk County. He turns off the engine, whips out his keys and opens the gate leading to an old phosphate mining pit.
O'Neal is an environmental specialist for Duke Energy Florida. As we navigate the sandy road around a lake, we see a flock of pelicans bobbing in water, reflecting the blue and white expanse of cloud and sky above.
Floating near them is an odd-looking platform the size of eight Olympic swimming pools. From the distance, it looks like a bunch of squares stitched together into a gigantic raft on one side of the pond.
"The part in the middle," O'Neal points out to me as we drive by, "is the actual floating solar arrays."
As we exit the ATV, O'Neal explains that this is atest project that produces only a fraction of the power generated by the hulking power plant nearby.
"We're at the Hines Energy Complex, which is a combined-cycle natural gas power plant. And attached to the power plant is the Hines cooling pond, which is the glorified radiator for the plant," O'Neal said. "It's a 1,200 acre, man-made cooling pond, which is a former phosphate pit. And on this, we built a three-quarters of a megawatt, or two-acre solar array on top of the cooling pond."
Here are the advantages
Project manager Shayna White said having solar arrays over water like this has several advantages. They don't have to lease new land from other property owners and there's little impact to the surrounding area.
"We're also looking at other benefits of floating solar, which would include better efficiency for the photovoltaic modules," White said. "The pond water should have a cooling effect, so they can produce their electricity more efficiently. In a larger scale, it would also prevent evaporation and help the pond stay it its stable level."
And it has another advantage: a positive use for one of the former phosphate mines that have scarred this region for more than a century.
If the project proves fruitful after it's completed in August, the 1,872 modules can be expanded with additional arrays.
The system will power about 100 homes. That's in contrast to the natural gas-fired Hines plant, which can power 1.5 million homes. But it would lessen the need for more generation from there during sunny days.
The pilot is part of Duke Energy's Vision Florida program, which is designed to test innovative projects such as microgrids and battery energy storage, among others, to prepare the power grid for a cleaner energy future.
It poses some challenges
Duke spokeswoman Audrey Stasko said this complements other "micro-grid" projects the company is working on.
"This is a pilot. That's exactly why we're doing it on a very small scale like this," Stasko said. "We want to look at the challenges, the limitations, and also the benefits. And that will help us decide if we want to do this on a larger, more operational scale."
Floating solar has already caught on in Asia.
The biggest one in the world in China can power about 52,000 homes. The largest one in the U.S. in New Jersey can power about 1,500 homes.
O'Neal said one of the challenges with being on a former mine is that clays and mud tend to muck up the pond during heavy rains.
There are other challenges, as well.
Too many solar panels covering the surface of a lake or pond can cause dissolved oxygen levels and water temperatures to drop, harming marine life. And there is ongoing research in other countries into whether the electromagnetic fields generated could harm the aquatic ecosystem.
White says that's not a problem in this disturbed region.
"That's definitely something that as a pilot project I think that will be looked at in the future," White said. "But one of the benefits of putting it on the cooling pond is this body of water is not used for that.
"So it's not a recreational body of water. There is wildlife, of course, here. But it's not used for any kind of consumption or selling of the fish or anything that's in here."
What they're doing, White says, could transform one of the most devastated landscapes in Florida into something that could create a cleaner environment in the future.
