Floating photovoltaic solutions
have been popular worldwide.
The 320 MW project of Huaneng Dezhou Dingzhuang Reservoir, which is currently the world's largest single floating photovoltaic power station.
The latest research released by the international academic journal Nature, Nature Sustainability, shows that placing floating solar panels in major reservoirs around the world can significantly increase power generation and achieve water conservation, thereby meeting the energy needs of thousands of cities.
This floating photovoltaic power generation technology, which places and fixes solar panels on the water surface and generates electricity by connecting underwater cables, is accelerating its global popularity. The function is the same as land solar power generation, but the power generation capacity far exceeds that of land, which not only saves valuable land area but also reduces water surface evaporation. It is a technological achievement in the field of solar energy that is tailored to local conditions and constantly innovated.
Annual power generation potential exceeds 9,000 terawatt hours.
According to Nature Sustainability, there are over 110,000 reservoirs worldwide that meet the standards for the application of floating photovoltaics, with a total area of 55,411,100 square kilometers. If 30% of the surface of these reservoirs is covered, that is, each reservoir has a coverage area of no more than 30 square kilometers, it can reduce water evaporation by 106 cubic kilometers per year, which is close to 300 million people's annual water consumption. At the same time, it can also achieve an annual floating photovoltaic power generation potential of 9,434 terawatt hours, which is about 2.4 times the total electricity generation in the United States in 2021 and more than three times the total electricity generation in the European Union in 2021. If the coverage rate is reduced to 20% or 10%, the average annual power generation of floating photovoltaics will be 7,113 terawatt hours and 4,356 terawatt hours, respectively.
One of the co-authors of the research paper and environmental engineer at the University of California, Santa Cruz, Elliot Campbell, said, "The potential for the floating photovoltaic solution
is amazing, more than 10 times the current solar power generation capacity. If you ask me when I can push this technology forward, I think it's now."
Based on factors such as reservoir location, population density, and power system, a total of 6,256 cities worldwide can achieve energy self-sufficiency through floating photovoltaic power generation, including 154 major cities. Campbell pointed out that the floating photovoltaic solution requires stable and shadowless water surfaces, and irrigation channels, quarry lakes, or reservoirs are ideal locations. In fact, this technology is largely beneficial for urban and rural areas with lower population density.
According to Wired, previous studies have shown that countries need to allocate 0.5% to 5% of their land area to solar power generation in order to achieve comprehensive decarbonization. The unit energy footprint of solar power projects is 70 times that of natural gas power projects.
Floating photovoltaics are developing the fastest in China.
Nature Sustainability summarizes the top 20 countries with the highest potential for floating photovoltaic solutions worldwide, with the United States leading with 1,911 terawatt hours per year, and China closely following with 1,107 terawatt hours per year. Brazil ranks third with an annual output of 865 terawatt hours, while India and Canada rank fourth and fifth respectively.
Based on the 2021 electricity consumption level in the United States, 30% of the country's reservoirs are equipped with floating photovoltaic solutions, which can meet nearly half of the country's electricity demand. As of now, a few countries such as China, the United States, and Brazil have begun to apply floating photovoltaic technology under limited capacity.
Our country has developed the fastest and achieved the most significant results in this technology. The 320 MW project of Huaneng Dezhou Dingzhuang Reservoir, undertaken by China Electric Power Construction Group Hubei Engineering Co., Ltd. in Shandong Province, is currently the world's largest single floating photovoltaic power station, with full capacity grid-connected power generation by the end of 2021.
At the end of last year, the largest floating photovoltaic project jointly built by China and Thailand was connected to the grid, with an annual power generation of 95 million kilowatt hours. In October 2021, a floating hydroelectric solar power plant built by China and Thailand in northeastern Thailand was put into operation, capable of generating 45 megawatts of electricity. The project adopts a hybrid system, which converts solar energy during the day and utilizes hydroelectric power at night.
Europe is also accelerating the deployment of floating photovoltaic projects. According to Reuters, the largest floating solar power plant in Europe began generating electricity in July last year and can provide electricity to approximately 1500 households.
Cost remains a development obstacle.
Improving power generation efficiency is one of the important advantages of floating photovoltaic solutions. Because the higher the temperature of the photovoltaic module, the greater its energy consumption, it is possible to lower the operating temperature of the photovoltaic module in water environments, thereby improving its efficiency.
According to "Technology Art" on the American Technology Trends News website, solar panels can provide shade, thereby lowering water temperature and reducing water surface evaporation. On the contrary, water can cool solar panels, making the efficiency of floating photovoltaics 15% higher than that of terrestrial photovoltaics. In addition, saving land space can free up more land for agriculture or habitat protection.
At present, the biggest obstacle to the application of floating photovoltaic technology is cost, as floating solar panels require anchoring systems for fixation, which requires additional cost expenditures. According to Sika Gazanku, an energy technology and policy researcher at the National Renewable Energy Laboratory in the United States, installing floating photovoltaic systems is 25% more expensive than on land and may reduce oxygen levels in water, harm fish and affect aquatic ecological balance, and even have a negative impact on water quality.
"Considering the aquatic ecosystem, we need to further study the potential impacts of floating photovoltaic solutions," admitted Jia Zanku. "At the same time, we also need to address a series of issues such as policy, planning, financing, regulation, technical support, and construction and maintenance."