Floating Solar PV: A New Solution for Offshore Solar Power

With the advancement of global "dual-carbon" goals, offshore solar PV, with its advantages of not occupying arable land, superior sunlight conditions, and high power generation efficiency, has become an important area for new energy development. It is estimated that the global potential installed capacity of offshore solar PV is approximately 4 billion kW, with a theoretical installed capacity exceeding 100 million kW in China, indicating broad development prospects. Currently, offshore solar PV projects in China have moved from the "pilot" stage to the "large-scale" stage, and floating solar PV, as a key direction for expanding incremental space at sea, is becoming the focus of the industry.

1. Two Main Forms of Offshore Solar PV

Offshore solar PV mainly falls into two technical routes: pile-based fixed type and floating type.

Pile-based fixed type: Suitable for near-shore shallow sea areas with a water depth of less than 5 meters, such as tidal flats and intertidal zones. It uses prestressed reinforced concrete pipe piles for fixing; the technology is mature but resources are limited.

Floating photovoltaic (PV) systems utilize a float and anchoring system to keep the PV modules afloat on the water surface. Suitable for deep-sea environments deeper than 5 meters, they offer greater adaptability and represent a major future development direction.

2. Technological Bottlenecks and Challenges

Despite the promising future of floating PV systems, the technology is still in the "demonstration and verification stage" and faces multiple challenges:

Environmental Adaptability: Harsh environments in deep-sea areas, such as high winds, waves, typhoons, and high salt spray, place extremely high demands on the equipment's corrosion resistance and wave resistance.

Shortcomings in the Support System:

Blow-molded floats: Weak wave resistance, lifespan less than 5 years, only suitable for enclosed waters.

Thin-film type: Relies on water pumps for stability, raising questions about reliability.

High freeboard structure: Excellent wave resistance, but excessively high cost, hindering large-scale deployment.

3. A Breakthrough Solution for Basalt Support Systems

Addressing the bottlenecks of traditional technologies, basalt offshore floating support systems offer a solution that balances performance and cost through material and structural innovation:

Material Innovation:

The float body uses PE100 grade polyethylene round pipe with a design life of 25 years; the support system uses basalt fiber composite profiles, which are high in strength and corrosion-resistant.

Structural Optimization:

Annular float design: Disperses wave impact and enhances resistance to deformation.

Spoke-type purlins: Connected by pins, they can rotate and swing, avoiding stress concentration.

Anchoring system: A three-section mooring line design (chain-polyester fiber rope-chain) adapts to complex seabed environments.

Ease of Operation and Maintenance: The annular float serves as an operation and maintenance channel, supporting modular replacement and reducing maintenance costs.

Currently, the support system has passed testing at the Tangjing Hydropower Station in Jiangshan City. A single support unit has a capacity of 1440kW, a wind resistance of 50m/s, and a wave resistance of 4 meters, placing it at an industry-leading level.

4. Large-Scale Application and Future Trends

China's offshore photovoltaic projects are accelerating their implementation, such as the Guohua Shandong 1 million kW project (the world's largest open-type offshore photovoltaic project). In the future, floating photovoltaic systems need further breakthroughs in cost reduction and efficiency improvement, as well as technological reliability, to propel the transition from "demonstration and verification" to "large-scale development." With the maturation of innovative technologies such as basalt support systems, offshore photovoltaics is expected to become an important pillar of "blue energy."