On October 14th, Caixin reported (Reporter Liu Mengran) that offshore photovoltaics, as a new way to utilize marine energy and develop photovoltaic resources, has received widespread attention in recent years. In September of this year, as reported by CCTV news, China Huaneng Group independently developed China's first set of wave-resistant floating photovoltaics successfully launched into the sea, marking a crucial step in the large-scale development of deep-sea offshore photovoltaics.

As an extension of land and water surface photovoltaics, companies started researching offshore photovoltaics as early as 2021, but specialized products only showed explosive growth last year. Caixin reporters noticed that component manufacturers including JA Solar Technology (002459.SZ), Trina Solar Co., Ltd., Smart Energy, Guangdong Quanwei Technology (300716.SZ), China Sunergy, etc., have introduced products specifically for offshore photovoltaics.

According to institutional statistics, the current planned or under-construction offshore photovoltaic projects have reached around 30GW. Thanks to the strong support of national policies and the active promotion of local governments, the offshore photovoltaic industry is undergoing a new phase of rapid development. However, many technical and ecological constraints are still the main challenges for the promotion of offshore photovoltaics in this stage.

Wang Le, head of the Trina Solar Co., Ltd. Photovoltaic Module Technology Engineering Center, told Caixin reporters that offshore photovoltaics exhibit the characteristics of 'three highs and two strengths': high temperature, humidity, high salt spray, strong wind, and strong waves have high requirements for components and systems. With the widespread application of technologies like double-layer coatings, the rational and orderly development of offshore wind power, and the promotion of distributed new energy development and utilization, offshore photovoltaics are expected to become an important force for China to achieve energy saving, carbon reduction goals, and steadily achieve carbon neutrality.

Further validation of reliability

The important background for the development of offshore photovoltaics lies in the increasing scarcity of land resources available for building large-scale power plants on land. Wang Le told Caixin reporters that most of China's major power-consuming provinces are located in coastal areas, providing a geographical advantage for offshore photovoltaics; meanwhile, offshore photovoltaics have less shading, vast sea areas for continuous power generation, fewer clouds at sea, conducive to increasing power generation.

However, compared to land-based photovoltaics, offshore photovoltaics need to extend their optimal service life, reduce the later operation and maintenance costs of power station systems and customers, and also face challenges such as salt spray corrosion, marine organisms, bird droppings erosion, and environmental water vapor infiltration.

To solve the difficulties and pain points in marine scenarios, the industry has been conducting technological experiments for many years. WuXi Benkang High-Tech Materials Co., Ltd. Chairman Zou Wankang told Caijing reporters that offshore photovoltaics face extremely harsh natural environments, such as high temperatures, high humidity, high salt spray, temperature fluctuations, and wet-dry alternation. As early as 2017, the company cooperated with Trina Solar Co., Ltd. to develop double-layer coating technology to prevent water vapor from corroding glass.

As transitioning from single-layer coating to double-layer would increase costs, and since the technical advantages and potential benefits were not clear at that time, this technology was not initially bullish. Moreover, at that time, the single-layer coating production line was running well, the length of the factory building was limited, and introducing double-layer coating meant that the production line needed to be modified. During the development process, the glass factory was clearly resistant.

However, by the end of 2018, Trina Solar Co., Ltd. successfully introduced double-layer coating technology to the market. In the following year, this technology was widely used. By 2019, with enhanced power of photovoltaic components and significantly improved corrosion resistance, newly built glass production lines began to consider and incorporate double-layer coating technology.

Currently, double-layer coating technology has become a "standard" for photovoltaic glass. In offshore photovoltaic scenarios, the application of double-layer coating and accessories such as sealed junction boxes has greatly improved water resistance and anti-corrosion performance. According to a set of empirical data provided by Zou Wankang from a Yinchuan outdoor base, the decay rate of double-layer coating is much lower than that of single-layer coating components, resulting in a significant increase in power generation: an increase of 0.85% in the first year, 1.06% in the second year, 1.1% in the third year, 1.5% in the fourth year, and up to 1.99% in the fifth year.

To ensure the stable operation of photovoltaic power stations, a high-sealing design for offshore photovoltaic module junction boxes and connectors is used to enhance water resistance. Additionally, high-corrosion-resistant frames are employed to guarantee the stable operation of photovoltaic power stations. For floating offshore photovoltaics, where cables are immersed in seawater for long periods, Trina Solar Co., Ltd., in collaboration with industry partners, has developed and tested waterproof cables and obtained the industry's first joint certification for offshore photovoltaic waterproof cables 2PFG 2962.

Various offshore photovoltaic components have been introduced.

Currently, pile-based systems dominate offshore photovoltaics, but from a long-term economic perspective, floating systems are expected to be the main form of offshore photovoltaic applications in the future. According to Trina Solar Co., Ltd.'s "Offshore Photovoltaic Module White Paper," more than 60 countries globally are actively promoting the construction of floating offshore photovoltaic power stations, with over 35 countries having 350 floating offshore photovoltaic power stations.

In the current planned projects in China, offshore photovoltaics to be built/under construction are mainly concentrated in coastal provinces such as Shandong, Jiangsu, Zhejiang, Fujian, etc. For example, Shandong Province has proposed the layout of two million-kilowatt-level offshore photovoltaic bases around the "CNI Bohai Sea" and "Along the Yellow Sea," with a total scale of more than 42 million kilowatts; in August of this year, Shanghai released the "Shanghai Offshore Photovoltaic Development and Construction Plan." It proposes to launch the first round of offshore photovoltaic project competitive allocation in 2024, with a scale of not less than 1 million kilowatts.

Driven by market demand, special offshore photovoltaic modules have frequently appeared in the past two years. Trina Solar Co., Ltd. can provide component solutions for both floating and pile-mounted systems; earlier this year, JA Solar Technology introduced offshore photovoltaic modules. In addition to using n-type battery technology, to cope with the challenges of the marine environment, this series of products also have features such as resistance to salt spray, ultraviolet rays, humidity, and hot spots.

According to JA Solar Technology's previous responses on interactive platforms, their products have been applied in offshore photovoltaic projects in Shandong, Anhui, and Guangdong. The company will continue to optimize product performance, enhance product adaptability and stability in the marine environment, expand more application scenarios and regions, and provide customers with higher quality and more efficient offshore photovoltaic solutions, supporting energy transformation.

Guangdong Quanwei Technology launched the "Tiger Whale XII" series of high-efficiency heterojunction cells in April this year, mainly for the offshore photovoltaic field. Certified by TUV Rheinland, the highest power can reach 742.7W. According to company sources, two technologies developed by Quanwei Technology, the "double-cycle self-cleaning anticorrosive glass" and "zero-water permeable special process," enhance reliability and reduce customer operation and maintenance costs.

During an interview with Caixin journalist, Wang Le mentioned that offshore photovoltaics face challenges in operation and maintenance, especially in cleaning and freshwater acquisition. He pointed out that there is currently a lack of in-depth research on offshore operation and maintenance in the industry, but it has already attracted attention. To address the problems faced by offshore photovoltaics and reduce costs, Trina Solar Co., Ltd. led the establishment of an offshore photovoltaic application ecological platform, starting from typical marine environments, establishing a component and material performance evaluation system against the challenges of "three highs and two strongs."

It should be noted that the current construction costs of offshore photovoltaics are still significantly higher than land-based photovoltaics. However, optimistic forecasts suggest that the growth in market demand has further reduced the cost per kilowatt-hour, which is conducive to larger-scale popularization, forming a growth loop. In the future, offshore photovoltaics will be integrated with industries such as aquaculture and hydrogen production to maximize value. Additionally, floating photovoltaics do not require complex and time-consuming infrastructure, facilitating rapid project construction and making them the mainstream of offshore photovoltaics.

Furthermore, as offshore photovoltaics continue to develop, the combination of offshore solar and wind power is considered a key direction for the future of marine energy. According to Wang Le, floating offshore photovoltaics can utilize the unused sea space within offshore wind farms; offshore photovoltaics can reuse submarine cables and power transmission lines from offshore wind power projects; wind and solar energy can effectively complement each other from a resource perspective; offshore photovoltaics can share the pile foundation of offshore wind power, providing a more convenient anchoring and installation method; this can significantly enhance resource intensiveness, increase power output and economic benefits of the generation fields.