Imagine a solar farm that rises and falls with the tides, its panels cooled by the sea below, generating electricity while waves crash against its floats. This is not a futuristic concept-it is already a reality. In July 2025, Sinopec commissioned China's first commercial floating offshore PV project in a full-seawater environment off the coast of Qingdao. The 7.5 MW station, spanning 60,000 square meters, demonstrates a remarkable advantage: thanks to the cooling effect of seawater, its power generation efficiency is actually 5-8% higher than equivalent land-based installations.
Constructing offshore solar farms is not as easy as just putting panels on floating devices, as they operate in one of the harshest environments for solar energy production: the ocean. According to Van Hua (Project Manager, SGS, a leading certification/testing organization), "There are numerous and ongoing challenges to consider when building an offshore solar array such as salt spray corrosion, high humidity/moisture, extreme temperatures, high wind, mechanical stress, and UV exposure". While continuing to develop further offshore, engineers are engaged in a silent battle with corrosion, moisture, and biofouling; this battle will determine if offshore solar can produce its full potential.
The Enemy: A Perfect Storm of Degradation
To understand how difficult it is for a solar panel to operate in the ocean, think about what happens to a typical offshore solar installation. For example, solar panels are continually covered with salt-laden water mist. Humidity levels are almost 100%. Waves beat down on both the floating structure and the anchors holding them in place. The underwater surfaces of the float and any submerged structure will be consumed by marine life looking for a place to attach itself. And all of this must take place while providing reliable electricity from the solar panel for at least 25 years!
Corrosion is the primary threat. Saltwater is an excellent electrolyte, accelerating electrochemical reactions that eat away at metal frames, connectors, and mounting structures . But the damage goes deeper. In standard salt spray tests conducted for marine certification, components must withstand Level 8 salt fog exposure-among the most severe classifications . Without proper protection, corrosion can infiltrate junction boxes, degrade electrical contacts, and ultimately cause system failure.
The infiltration of moisture is just as dangerous as the infiltration of water. Water vapor is capable of penetrating the encapsulations of solar panels, resulting in potential induced degradation (PID) of PV cells. During the Atlantic Rowing Expedition of 44west, SGS conducted a series of tests for solar panels intended for use in ocean waters. Incending extreme conditions, engineers submerged the solar panels in salt water while applying high voltage to them. The aim of such tests was to be sure that there would be no electrical leakage regardless of how high the waves are.
Biofouling occurs when marine organisms like algae and barnacles clog the surface. Biofouling not only increases pressure on floating structures, it also has an impact on solar panels as they can be shaded by the organism or corrode locally. Traditionally, antifouling paints were created with the help of biocides which have a number of negative impacts on marine ecological systems thus creating a contradiction for eco-friendly projects.
Testing to Destruction: Proving Fitness for Purpose
Before any offshore solar system can be deployed, it must prove itself in the laboratory. The testing protocol for the 44west expedition panels is instructive:
Visual inspection checks for cracks, delamination, or sealing defects that could become entry points for corrosion
Insulation resistance testing verifies that no dangerous current can leak from internal circuits to the frame
Wet leakage current testing submerges panels in saltwater while applying high voltage, simulating worst-case ocean conditions
Salt mist corrosion testing exposes components to concentrated salt fog for extended periods
Mechanical load testing confirms the structure can withstand wind, waves, and vibration
The results from rigorous testing build confidence that offshore solar can deliver on its promise. As Van Hua notes, "Ensuring the quality and durability of solar panels helps extend product lifespan, reduce failure rates and lower the overall cost of clean energy systems".
The Road Ahead: Standardization and Scale
Recognizing the strategic importance of offshore solar, China's standardization bodies are moving to establish clear technical guidelines. An ongoing national effort to create a "Technical Specification for the Control of Corrosion in Offshore Photovoltaic Systems", primarily developed by Shandong Electric Power Engineering Consulting Institute, is now underway. This initiative involves a wide range of industry experts such as LONGi, Huawei and several research institutions that are contributing to the establishment of this National Standardisation Project and subsequently will be developed into a soon to be published document.
Offshore solar is moving from being an experimental idea to being a legitimate industry, with offshore solar projects now operational and stricter standards enroute. The Sinopec project is generating 16.7 million kWh of renewable power annualy while displacing 14,000 tons of carbon emissions from the atmosphere and has plans to expand its capacity to 23 MW.
Although there are many challenges that coastal areas must face due to saltwater exposure, storms and wind; through innovative materials; intelligent design; and extensive testing, the solar industry has developed ways to be successful in utilizing solar energy where land meets ocean. As a result, solar has opened new renewable resources to support up to 71% of Earth's surface that is covered by oceans.
