Water and desert photovoltaic technology: potential for future development and application prospects

After the rapid increase in photovoltaic installations in recent years, the installation of photovoltaic systems this year will exceed 450 GW. The market must start looking for more photovoltaic application scenarios to cope with the problem of gradually decreasing suitable land resources. This year, at SNEC, the world’s largest photovoltaic exhibition, many component manufacturers have exhibited components adapted to different application scenarios, among which the applications in water and desert environments are particularly eye-catching and provide the market with new business opportunities.

These application scenarios can not only effectively solve the problem of land resource limitations, but also combine with the local natural environment to achieve mutual benefit in economic and ecological benefits. This article will explore the application scenarios, technical characteristics and future development potential of water photovoltaic and desert photovoltaic technologies in depth, and analyze the advantages and challenges of these two technologies in practical applications through specific cases.

(I) Application and characteristics of water photovoltaic application scenarios

Water photovoltaic power generation is an emerging and potential technology. It has multiple advantages such as environmental protection, technical economy and social benefits by installing photovoltaic components on the water surface to generate electricity. In terms of installation, in addition to using environmentally friendly materials to protect the ecological environment, it can also reduce construction costs through simple and fast construction methods, while avoiding the land property rights issues encountered in land photovoltaic development.

At present, water photovoltaics are divided into two types, namely offshore projects and terrestrial water projects, of which terrestrial water projects include lakes, reservoirs, abandoned mine construction, artificial lakes and ponds and other different application scenarios.

In terms of component selection, double-glass components can better solve the problem of water vapor permeability in the scenario of water photovoltaics, and can increase power generation by 5-10% compared to ground-based photovoltaics. In terms of application design, waters with a depth of less than 3 meters usually use pile foundation fixed type, while waters with a depth of more than 3 meters mostly use floating type (floating tube type, pontoon type). Since the construction scheme on water is simpler and faster than on land, many developers have realized this business opportunity and started to develop on water sites, which also brought differentiated markets to component manufacturers. For example, at this SNEC exhibition, many manufacturers also began to exhibit various photovoltaic modules for water scenes, reflecting the development potential of water surface photovoltaics.

As the application of water photovoltaics is gradually valued, China’s offshore photovoltaic projects are expected to have a scale of 2-3 GW this year, and are mainly concentrated in coastal areas such as Shandong, Jiangsu, Zhejiang and Fujian. At present, some projects will be planned to be built in the second half of this year and the first half of next year, and will start to pull goods in the fourth quarter. Among them, Sunshine Water Surface Photovoltaic Company is the company with the highest market share at present, and it is also the only company that can build photovoltaic sites in waters 100 meters deep.

In addition to the application of large-scale offshore photovoltaics, there are many undeveloped areas in China’s terrestrial water bodies. The development projects are divided into centralized and distributed. The former’s terrestrial water body projects are mostly from coal mining subsidence areas, with a scale of about 50-200 MW, while the latter are mostly pond water surface projects, with a single case capacity of 5-30 MW. In summary, terrestrial water body projects have great potential. Overall, InfoLink expects that China’s cumulative installation of floating photovoltaics will exceed 5 GW this year, and the global cumulative installation is expected to reach 7-8 GW.

Although floating photovoltaics will contribute to the continued growth of photovoltaic installations, there are still many difficulties in the development process. In addition to the difficulty of construction and subsequent operation and maintenance, the market’s concerns about water quality and aquatic ecology also need to be verified by more cases. In recent years, manufacturers have also begun to provide solutions to these opinions.

For example, in the 60 MW reservoir project in Singapore, Sunshine Water Surface Photovoltaic Company used food-grade materials in the water photovoltaic project to ensure that the water quality was not affected, and passed strict inspections and quality control to ensure the safety of drinking water and eliminate the public’s concerns about the impact on water quality. As more companies introduce innovative technologies and implement strict environmental protection measures, and the number of successful cases increases, the social acceptance of water photovoltaics is gradually increasing, and it is expected that more consensus can be reached between environmental protection and stakeholders to achieve sustainable development.

(II) Application scenarios and characteristics of desert photovoltaics

Desert photovoltaic power generation is to achieve efficient and economical power generation benefits through strong sunshine, vast large-scale sites, etc. In the global desert photovoltaic plan, China is a very representative country. The most famous of them is the national large-scale base “Shagohuang” plan in the northwest regions of Xinjiang and Inner Mongolia.

As the first large-scale wind and solar base plan of 10 million kilowatts, the first phase of 1 GW has been successfully connected to the grid for power generation, and the second and third phases are under construction. As the recent centralized plans are mostly affected by policies such as land compliance review and ecological conservation, and the desert land is relatively easy to obtain, developers are gradually going deep into the inland desert areas to look for land; in addition, building photovoltaic sites in desert areas can also improve the effectiveness of sand control, so that photovoltaic sand control projects are gradually gaining attention.

In terms of the selection of components, the desert environment has extremely high technical requirements for photovoltaic components. Considering the high temperature, large temperature difference between day and night, high ultraviolet rays and sandstorms in the desert area, the high temperature resistance and wind and sand resistance of the components are extremely high. At present, some component manufacturers are also stepping up breakthroughs in technology, such as increasing the thickness of component glass to resist wind and sand, introducing dust and sand prevention technology, and improving the high temperature resistance of components.

Test conditions. In terms of application scenarios in the desert, some regions also have special regulations. For example, Inner Mongolia has relevant regulations on sand control plans, requiring the site project to set up battery and component production capacity locally, and requiring stable peak load regulation and self-use with energy storage.

Therefore, manufacturers still need to consider the above points when building sites in the area. In addition, the current sand control plan in the northwest region is still limited in development due to feeder transmission problems, and electricity cannot be transmitted to other provinces in large quantities, which has prompted some manufacturers to pay less attention to desert photovoltaic projects than other application scenarios. Therefore, the demand for sand control projects this year is expected to be relatively limited.

Both water photovoltaic and desert photovoltaic technologies indicate a special direction for the development of renewable energy in the future. In order to maximize the economic benefits of water photovoltaic and desert photovoltaic, some water photovoltaic projects use multi-functional development such as fishery farming and leisure tourism to form a comprehensive utilization model of “fish-light complementarity”.

In terms of desert photovoltaic, there are currently projects that use photovoltaic power generation, agricultural planting, and ecological restoration as concepts to create multi-functional desert parks. Although both are still niche markets in global applications at this stage, with the continuous advancement of technology and continued policy support, they still have certain development potential in the future, and are expected to achieve a win-win situation between economic and environmental benefits.