The story of Singapore's floating solar farm in the Straits of Johor is a fascinating one, filled with unexpected twists and turns. It's a tale of innovation, caution, and the challenges of bringing cutting-edge technology to the open sea. The farm, a marvel of engineering, was designed to harness the power of the sun on the water, but it quickly became clear that the real challenge was not the solar panels themselves, but the barnacles.
The farm, built by Sunseap Group, consists of 13,312 solar panels, 40 inverters, and over 30,000 floats, all rated at 5 megawatts-peak. It was installed in the channel separating Singapore from Malaysia, with a view to generating clean energy. However, the real test of this project was the wave-tank test in 2020, which identified barnacles as a potential issue. Despite this, the farm was built, and it has been operating for five years, still carrying its original rating.
The barnacles, as anyone who has kept a boat in salt water knows, are a persistent problem. They cement themselves to surfaces, making removal difficult and costly. The farm's designers and builders were aware of this, having tested for corrosion, wave motion, and biofouling, including barnacles and algae, in a wave tank before installation. Yet, the barnacles have proven to be a persistent issue, and the real question is why they are so difficult to manage.
The impact of barnacles on the floats is significant. They add weight and drag, affecting the buoyancy calculation and the overall behavior of the array when ships pass by. A study on the FLOATGEN floating wind demonstrator found that barnacle growth on mooring lines increased their thickness by 7-32%, highlighting the structural impact of these organisms.
However, the literature on floating PV modules is less conclusive. While degradation rates over five years resemble those of land-based panels, the long-term durability of floating solar systems remains unproven. The lack of standardized measurement protocols and in-situ offshore data makes it challenging to assess the true cost of barnacle management over a 25-year asset life.
The industry is now grappling with this uncertainty, leading to the development of new standards. DNV has published guidelines for structural design and station keeping, recognizing the unique challenges of floating solar in harsh offshore environments. Singapore's SERIS has also been working on national and international standards, but the open sea remains a complex and uncharted territory for this technology.
In contrast, freshwater environments, where most installed capacity is found, do not face the same barnacle issues. Projects in Taiwan, China, and the Netherlands have tackled the problem in different ways, but the open sea presents a unique set of challenges. The potential for floating solar in offshore areas is vast, with estimates suggesting it could support over 718 TWp of capacity, but the cost of barnacle management in warm water remains a critical question.
The Woodlands array, while a success in terms of mooring and operation, highlights the need for further research and standardization. The barnacle, once a predicted issue, has become an unpriced line item in infrastructure finance. Until the true cost of barnacle management is determined, it remains a challenge that must be addressed for floating solar to reach its full potential.
