The Huge Potential of Floating Photovoltaic Systems

The National Renewable Energy Laboratory (NREL) elaborated on the huge potential of floating photovoltaic systems. Researchers at the National Renewable Energy Laboratory estimate that installing floating solar photovoltaic devices on over 24000 artificial reservoirs in the United States can generate approximately 10% of the country's annual total electricity generation. This discovery was published in the journal Environmental Science and Technology, revealing for the first time the potential of floating photovoltaic systems in the United States. Although the United States was the first country to showcase floating photovoltaic panels and installed them on a floating bridge in an irrigation pond in Napa Valley, California 10 years ago, this idea has not been widely recognized nationwide. As of December 2017, the United States had focused on installing large-scale onshore photovoltaic power stations, while there were only seven floating photovoltaic power stations.

However, the deployment of the floating photovoltaic system overseas is increasing, and by the end of last year, there were over 100 floating photovoltaic power stations worldwide. Among the 70 largest floating photovoltaic devices, 56 are located in Japan. Floating photovoltaic panels were installed in Walden Lake, Colorado River (photographed by Dennis Schroeder/NREL)"In the United States. This is a niche application, and in other regions, such demand is real." "We expect this application to take off in the United States, especially in areas where there is a significant conflict between solar land and agricultural land." Mackneck and his NREL co-authors Robert Spencer, Alexandra Aznar, Adam Warren, and Matthew Reese estimate that if solar panels were installed in water instead of land, they could save about 2.1 million hectares of land. The use of floating photovoltaics has other benefits, including reducing water evaporation and inhibiting the growth of algae.​ The lead author of the paper, Spencer, added, "In some cases, the benefits can be even greater than what is stated in the paper. Our team used a 'strict assumption' method to estimate the potential total power generation and benefits, providing a very conservative estimation result."

The NREL team also found that operating floating photovoltaic power generation next to hydroelectric facilities based on existing transmission infrastructure can improve energy output and save costs. Warren, Director of the NREL Integrated Applications Center, believes that "the rapid decline in solar photovoltaic module prices will make floating solar power an emerging industry." "The cost of acquiring and developing land is becoming a major part of the cost of solar energy projects. In some places, islands and land prices are quite high, and we can foresee that floating solar energy will soon be accepted and put into use." According to a Bloomberg New Energy Finance report, the global photovoltaic installed capacity reached 98GW in 2017, an increase of 31% from 2016, with China accounting for 53GW, accounting for more than half of the global total capacity. In the development of floating photovoltaic systems, compared to countries such as the United States, Japan, the United Kingdom, and South Korea, China started relatively late and is in its early stages.

However, due to the vast water area in China, which accounts for 4.735% of the national territory, and the strong demand for electricity, floating photovoltaic power stations are developing rapidly in China. It is expected that by 2020, the Asia Pacific region will dominate the global floating power plant market. At the end of 2015, the first floating photovoltaic power station in China, located in the reservoir area of Xucun Hydropower Station in Bai Autonomous Prefecture, Dali City, Yunnan Province, was completed. In 2017, China built the world's largest floating photovoltaic power station - Anhui Huainan Power Station, with 160,000 solar panels and a total installed capacity of up to 40MW. The generated electricity can meet the electricity needs of 15,000 households.

As a typical example, this power station not only leads the world in scale, but also highlights the advantages of floating photovoltaics to the fullest. It effectively improves power generation efficiency, saves land costs, and optimizes water bodies. Of course, there are also shortcomings. Compared to land-based power stations, the construction and operation costs of water power stations will also increase. Based on the current situation in our country, we will discuss the advantages of developing floating photovoltaics and what other issues need to be considered. 

Development advantages:
The per capita land area in our country is relatively small, and developing floating photovoltaic systems can save land. Due to the permanent occupation of land by photovoltaic systems, water-based photovoltaics effectively activate the land. On water, due to the water cooling effect of photovoltaic panels and the almost dust-free environment, the power generation efficiency is higher than that of terrestrial photovoltaic systems. The evaporation in northern China is greater than the rainfall, and the imbalance of water balance leads to increasingly severe climate drying. Water surface photovoltaic systems can reduce water evaporation by covering a large amount of water surface. China has abundant water resources, 32,000 kilometers of coastline, 86,000 reservoirs (as of the end of 2012), and a total area of 91,000 square kilometers of lakes, making it suitable for the development of water-based photovoltaics.

Question to be considered:
The selection of materials for the floating platform requires innovation. On the one hand, the floating platform must have good corrosion resistance, low density, frost resistance, wind and wave resistance, and other properties. On the other hand, it is necessary to consider the difficulty of obtaining and processing materials, as well as the economic viability of costs. Experiments must be conducted at appropriate locations. It is possible to consider conducting experiments in lakes and reservoirs in calm climate areas within the mainland. Like the Jinsha River, it has the characteristics of abundant and stable runoff, low wind speed, good lighting conditions, and good development conditions. In addition to achieving capacity grid connection, floating photovoltaics can also be used as distributed energy storage photovoltaic systems. In this case, the selection of energy storage equipment is more crucial. The performance, cost, and adaptability of the battery to water environment operations need to be considered.