Solar Panel Installation Teams Are Taking Advantage of Liquid Project Sites
Floating solar farm project in Huainan, China
PHOTO BY KEVIN FRAYER/GETTY IMAGES
It turns out water and electricity can mix well—at least when it comes to renewable power. Floating solar projects are popping up around the world, as teams seize on the unique advantages offered by reservoirs and other artificial bodies of water. In many countries it is easier to gain regulatory approvals for floating array projects than on-land projects, and adjacent water can keep photovoltaic cells cool, making them more efficient. But benefits go beyond power generation. By covering water surfaces, arrays can reduce evaporation rates and prevent algae blooms.
“I expect that after some more projects and pilots are completed, a new market will be created.”
—Mathias Ludwig, Ciel & Terre, São Paulo, Brazil
The largest-ever floating solar project closed in June near the Chinese city of Huainan. Boasting 160,000 solar panels, the 40-mega-watt system is located atop a collapsed coal mine. In July, sector mainstay Ciel & Terre International wrapped up a €400,000 pilot project to install 840 floating solar panels at the Alto Rabagão Dam in Portugal. The facility is the world's first combined hydroelectric and solar power plant.
But teams are still grappling with some technical issues that can undermine floating projects' benefits. These include how to prevent panels from moving across bodies of water and deteriorating due to moisture exposure.
Take the 16-month Alto Rabagão Dam project sponsored by Energias de Portugal. It aimed to prove the viability of installing floating solar panels at hydroelectric plants around the country. The project was successful in terms of schedule, budget and scope, but Paulo Pinto, who served as a project manager, says the pilot system has no economic viability. In part that's because engineering challenges drove up costs: The team had to account for dramatic water-level variations since the project was on a dam, as well as high winds and waves common in the region. So it designed an elastic cable system to anchor the panels to the bottom of the dam, allowing them to rise and fall with the surface level while remaining relatively stationary.
Future projects could be viable if implemented at scale, because the mooring system is a relatively fixed cost and the panels themselves will cost less when purchased on time and in bulk, says Mr. Pinto, senior electrical engineer, Energias de Portugal, Lisbon, Portugal. “We want to study bigger solutions and test other locations, but we are still collecting data and analyzing the market.”
In Brazil, Ciel & Terre teams are perfecting their approaches to executing floating solar projects. Strict environmental laws make it difficult to build around dams or lakes—but not on top of them. In the state of São Paulo, projects under 5 megawatts do not require regulatory approval if they do not impact vegetation, says Mathias Ludwig, project manager, Ciel & Terre, São Paulo, Brazil. This gives floating projects a distinct advantage over similar land-based projects.
For a 304-kilowatt floating project completed last May on a rainwater accumulation pond in the state of Goiás, the Ciel & Terre team designed the anchoring and flotation system. It delivered the equipment for the client to install while providing oversight and training.
As the organization looks to expand into other regions of Brazil, Mr. Ludwig anticipates transportation and logistics challenges. The flotation systems take up a lot of space, and moving them could get expensive—especially if the project site is in more remote parts of the Amazon. Other challenges include how much Ciel & Terre teams should rely on outside suppliers (which can often trigger delays) and how time-consuming it can be to cultivate relationships with key stakeholders. Strong relationships built on in-person meetings—which can necessitate a lot of travel—are needed to get things done.
“In Brazil, everything works on the personal level. Since we are developing a lot of new things, involving new suppliers and new applications for different products, we know this is just something to deal with,” he says.
Still, interest remains high and—as long as land remains scarce and expensive—proponents are confident that floating solar panels have a bright future. Clients have to “see to believe,” says Mr. Ludwig: “I expect that after some more projects and pilots are completed, a new market will be created.” —Ambreen Ali
With open land growing more scarce (and expensive) in many places, expect floating solar arrays to keep multiplying on various bodies of water.
RENT A RESERVOIR
If all goes well, a portion of the Olivenhain Reservoir near Escondido, California, USA should be covered by 24,000 solar panels by the end of this year. San Diego County Water Authority, which signed a project contract with Pristine Sun last year, will get a monthly fee for renting the reservoir surface and a portion of all power generated.
Australia's largest floating solar array project, community-funded and sponsored by the city of Lismore, started in October at the city sewage ponds. All power generated will help keep Lismore's sewage treatment plant running.
MORE TO DRINK
A 960-solar-panel project jointly completed by Istanbul Enerji and Istanbul Water and Sewerage Administration on Istanbul, Turkey's Lake Büyükçekmece in August aims to deliver two main benefits: prevent up to 210 tons of carbon dioxide emission annually and reduce water loss due to evaporation. The lake provides drinking water to city residents.