Flexible Floating Photovoltaic Systems - A Novel Solar Energy Utilization Technology
I. Background of Flexible Floating Photovoltaic Systems
Traditional photovoltaic systems are mostly deployed on land. With the increasing cost of land resources and policy promotion, inland water surfaces such as reservoirs and lakes have gradually become new frontiers for photovoltaics. In recent years, offshore floating photovoltaics, which have greater spatial potential, have attracted the attention of more and more countries. However, unlike the static water environment of inland areas, ocean areas have stronger waves and winds, posing higher requirements on the fatigue resistance of photovoltaic modules and structural systems. Traditional rigid modules are prone to damage under long-term wave loads, while flexible floating structures are a new solution proposed to address this issue, which can better adapt to wave motion, reduce structural stress, and enhance the overall stability and longevity of the system.
II. Structural Configuration of Flexible Floating Photovoltaic Systems
Flexible floating photovoltaic systems are typically composed of three core components: a flexible support structure, photovoltaic modules, and a mooring system.
Photovoltaic modules are directly laid on tensioned flexible membrane materials or elastic substrates, which must possess good tensile strength, UV resistance, and seawater corrosion resistance. Compared to traditional rigid platforms, this flexible design enables the structure to conform to wave undulations, significantly reducing the load impact caused by waves. The entire photovoltaic platform is supported by annularly or radially arranged buoys to achieve stable floating. Buoys are often made of high-density polyethylene or composite materials, combining lightweight, high buoyancy, and durability. The periphery of the platform is connected to the seabed through an anchoring system and flexible cables to resist overall displacement caused by wind and waves. In terms of power transmission, the system uses flexible waterproof cables, coupled with floating cables or sliding rail structures for dynamic compensation. The overall design emphasizes modular arrangement, ease of maintenance, and reliability for long-term operation.
III. Application Cases Foreign Case
The La Palma Boost project in Spain. In December 2023, Ocean Sun completed the construction of a 275kw offshore flexible floating photovoltaic demonstration system in the La Palma sea area of Spain, which is currently the largest offshore photovoltaic platform in Europe. Funded by the EU Horizon 2020 program, this project aims to verify the adaptability and engineering reliability of flexible floating PV systems in marine environments. The system adopts a flexible membrane structure supported by circular buoys and has passed analysis and testing by Innosea, a third-party engineering company, and obtained design verification from DNV for site conditions. The three-year research and development work of this project has provided actual operational data, which is of great reference value for subsequent commercial promotion.
Domestic case: The floating photovoltaic pilot project in Haiyang, Shandong, China. In 2023, the Shandong branch of State Power Investment Corporation constructed a 500kw floating photovoltaic system in the southern waters of Haiyang, Shandong. The project is located in the offshore area approximately 30 kilometers from the shore and at a water depth of 30 meters, and is deployed within the No.3 offshore wind farm in the southern part of the peninsula, achieving co-location with the wind turbines. The project utilizes Ocean Sun's flexible thin-film floating photovoltaic technology and a dedicated anchoring system. The system comprises two floating units, each with an installed capacity of 250 kw and a diameter of approximately 53 meters. Each platform is equipped with 770 double-sided, double-glass, monocrystalline photovoltaic modules. The floating structure is composed of high-density polyethylene annular buoys, secured through four mooring points and 12 anchor cables. The photovoltaic modules are connected to the flexible thin film via sliding rails and are in direct contact with seawater for natural cooling.
Currently, both projects are in the experimental or small-scale commercialization phase, and the data collected can serve as technical references and performance verifications for subsequent larger-scale deployments.
IV. Current Major Technical Challenges
Despite the significant advantages exhibited by flexible floating photovoltaic systems in offshore photovoltaics, several key technical challenges still persist. (1) Material Durability: Flexible films and photovoltaic modules must withstand ultraviolet radiation, seawater corrosion, and mechanical fatigue over the long term, demanding extremely high material performance. (2) Hydrodynamic Stability: The system must remain stable under the combined effects of waves, tidal currents, and wind loads to prevent drift or damage. (3) Cable Laying and Connection Technology: The wiring in flexible systems must ensure reliable connections and waterproof performance during system movement. (4) Maintenance and Monitoring Difficulties: The high maintenance costs of offshore systems necessitate higher requirements for real-time monitoring, intelligent diagnosis, and other technologies.
V. Application Prospects and Development
Trends Flexible floating photovoltaic systems are gradually moving from demonstration to large-scale application. With the continuous advancements in marine engineering, materials science, and intelligent control technology, it is expected that systems with larger scale, higher efficiency, and lower cost will be deployed in the future. From a global perspective, countries and regions with abundant sunshine and tight land constraints, such as Southeast Asia, coastal Africa, and the Middle East Gulf region, will be the main markets for flexible offshore photovoltaics.
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