Singapore, a nation with limited land area, has increasingly looked to its surrounding waters to meet ambitious renewable energy targets under the Singapore Green Plan 2030. One such initiative, the Woodlands Sea-Based Floating Photovoltaic (OFPV) System in the Strait of Johor, aimed to harness solar power offshore. However, this pioneering project has encountered an unexpected and significant challenge from marine life.
A Solution to Land Scarcity
With a population of nearly six million people packed into just 280 square miles, Singapore has little room for expansive land-based solar farms. While rooftop solar installations contribute, they are insufficient to meet the country's clean energy goals. This scarcity drove developers like EDP APAC and its subsidiary Sunseap Group to explore floating solar solutions at sea.
The Woodlands OFPV System is a five-megawatt project, one of the world's largest floating solar installations in a marine environment. It comprises 13,312 solar panels mounted on over 30,000 pontoons, spanning 12 acres of the Strait of Johor off Singapore's northern coast. The facility, equipped with 40 central inverters and a large transformer, is designed to produce approximately six million kilowatt-hours of clean electricity annually, cutting over four thousand metric tons of carbon emissions each year.
The Unexpected Foe: Marine Growth
Engineers initially focused on ensuring the floating structures could withstand saltwater corrosion, waves, tides, and strong winds. A custom tension system made from marine-grade materials was anchored to the seafloor to maintain stability and prevent movement. The sea also offered an advantage: cooler water temperatures that could enhance panel efficiency compared to land-based installations.
However, the biggest hurdle proved to be not the elements, but marine organisms. The warm tropical waters created ideal conditions for prolific growth. Algae, sea squirts, and thousands of barnacles rapidly attached themselves to the submerged pontoons and mooring lines. Over time, these marine organisms formed thick layers, dramatically increasing the mass of the floating system by nearly 43 percent.
Impact on Operations and Durability
- Reduced Buoyancy: The added weight pushed the pontoons deeper into the water, diminishing their ability to float effectively.
- Mechanical Strain: As platforms sank lower, heavy steel hinges designed to accommodate wave movement began to lock, impairing the system's flexibility.
- Corrosion Risk: The lower position increased the likelihood of seawater splashing onto electrical connectors, heightening the risk of corrosion and potential operational failures.
Seeking Solutions to Biofouling
To combat this biofouling problem, workers initially resorted to manual scraping of marine growth. Chemical anti-fouling treatments were also employed to slow down further accumulation. Engineers are now actively testing new designs, including elevated geometric pontoons and submerged load sensors, which can track weight changes caused by marine growth.
Singapore's experience highlights a critical lesson for other land-scarce nations considering offshore solar farms: successful deployment requires not only robust structural engineering but also comprehensive strategies to manage the inevitable challenges posed by marine life. While new pontoon designs and protective coatings offer promise, the long-term costs of cleaning and maintenance remain uncertain as multi-year trials continue.