Recently, a video of "the first far-reaching sea scenery floating photovoltaic project ran away" circulated on the network. The video shows that the film and photovoltaic modules in the middle of the power station are missing, and many netizens have expressed doubt and confusion.
Financial reporters confirmed from informed sources that the project is a 20 MW far-reaching floating photovoltaic 500 kW demonstration project of the Shandong Peninsula South No. 3 offshore wind Farm of the State Power Investment, located in the south sea of Haiyang City, Shandong Province. An offshore photovoltaic technology expert who is familiar with the project and works for a private company told financial reporters that the "photovoltaic running" event shown in the video did not happen in the near future, but shortly after the photovoltaic project "launched" last year. At that time, the accident once triggered a high level of concern in the industry. Some netizens expressed concern about the whereabouts of the lost photovoltaic modules in the video message. The expert said that based on the technical solution of the project, the probability of the lost photovoltaic modules and films is not "floating away", but "sinking", so the impact on the safety of navigation is limited.
Why Components and Films run away
According to an article previously released by the official wechat public account of the State Power Investment, on October 31, 2022, the 20 MW far-reaching sea floating photovoltaic 500 kW demonstration project of the Shandong Peninsula South No. 3 offshore wind Farm of the State Power Investment successfully generated electricity, becoming the world's first far-reaching sea landscape floating photovoltaic demonstration project.
The article released by the State Power Investment said that different from the existing offshore photovoltaic in sheltered sea areas and offshore areas, the demonstration project is the world's first floating offshore photovoltaic engineering demonstration project studied and built in the offshore distance of 30 kilometers, the water depth of 30 meters, and the extreme wave height of 10 meters in the "double 30" Marine environment. The elastic film technology of Ocean Sun, Norway, the anchoring system design and the Marine environment resistant photovoltaic modules customized by GCL were jointly constructed by Beijing Xuneng Company and Tianjin Port and Navigation Company.
Offshore photovoltaic power stations are divided into two types: pile foundation type and floating type. At this stage, pile foundation type is the main type, mostly in the tidal flat and intertidal zone. At present, the construction of offshore floating power stations is still in the process from 0 to 1. Normally, the components of floating surface power plants rely on floating bodies to float above the water surface, which has a natural advantage in adapting to changes in water level. For irrigation reservoirs with large area and deep water depth, which are not suitable for piling operation and fish ponds in whole waters, floating surface power station has a more flexible application environment.
For the technical logic of the project accident, the above experts analyzed that there are two large possibilities for financial reporters.
First, according to the Norwegian company Ocean Sun, the structure of the power station film is shaped like a bowl, surrounded by a complete motor system, as long as the sense of water will not stop pumping. However, considering that the project is off the grid and other reasons, no pump is equipped, and the wave height in Yantai sea is more than 6 meters, the film is filled with water after the wave surges over, which may cause the film damage or overall fracture, and the failure of the buoyancy ring, which may eventually lead to the bottom of the film and components.
The second is that the system is paired with customized bezel-less photovoltaic modules, which are at risk of breakage under violent waves, which may cause the film to puncture and subsequent effects.
Another offshore photovoltaic technology expert working for a central enterprise also explained the above logic to financial reporters, saying that this is the mainstream speculation in the industry, that is, wave conditions, mechanical equipment problems are the main cause of the project accident. However, the State power investment has not made a public statement and characterization of the cause of the accident, so it is not possible to conclude.
The two experts also mentioned that it is feasible to make flexible solutions in closed seas without strong winds and waves. However, once it comes to the open sea, the wave is high and the water is deep, the bottom has no rigid support, and the impact pressure of the wind wave can not be transmitted to the attachment. There is also a binding rope between the membrane structure and the buoyancy ring, and the tensile limit is also greatly reduced when exposed to Marine ultraviolet light. If these weaknesses are not overcome, it is easy to leave security risks for the later system.
In addition, a number of industry experts who study offshore photovoltaic technology told financial reporters that the accident was caused by technical reasons.
How can offshore PV development be more robust
In recent years, with the large increase of pavement photovoltaic power stations, there is a serious shortage of land resources that can be used for installation and construction, which restricts the further development of such power stations. Local governments and enterprises have turned their attention to water floating power stations, hoping to create a new engine for photovoltaic growth.
The above technical experts working for a private company said that there are several mainstream technical routes in the offshore photovoltaic market: First, the elastic film technology of Norway's Ocean Sun company is applied in the North Sea of Europe, Singapore and other places; The second is flexible array, such as a new way and Three Gorges, State power Investment Jidian Shares and other central state-owned enterprise cooperation projects; The third is HDPE float box, representing enterprises such as sunshine power supply and Norseman, which produces plastic floats.
The relevant person in charge of two private PV module companies, Longi and JA, also told reporters that the company has technical reserves or solutions for offshore PV. "The challenge of doing offshore PV is all-round, both in terms of product technology to have corrosion resistance, wind and wave resistance, but also to deal with policy uncertainties."
The unevenness of heat and cold is the common feeling of many people in the industry. "Now the provinces present two extremes, some have not made a clear statement so far, some are very strong, by the end of this year there are some offshore photovoltaic projects have actually completed the grid." At the enterprise level, the central state-owned enterprises are more optimistic about the prospects of offshore photovoltaic, they generally hope to take more high-quality resources in the early stage, so they will also do some preliminary experiments, choose about one megawatt of photovoltaic sea area, choose several technical routes to do comparison and demonstration."
Another general consensus is that existing offshore PV projects are almost all difficult to establish from an economic point of view.
"Although there are occasional twists and turns in the process of exploring technology, we are still very optimistic about the blue ocean market of offshore photovoltaic, after all, it is an indisputable fact that land resources are increasingly scarce." In addition, offshore photovoltaics can also solve some difficulties that terrestrial photovoltaics cannot solve. For example, some islands without energy can be powered by offshore photovoltaic, and can also cooperate with far-reaching sea farming, combining offshore wind power and photovoltaic to create Marine pastures. In addition, the electricity generated by offshore wind and photovoltaic is converted into hydrogen energy, which can be mixed and transmitted to the corresponding base station on the shore through the oil pipeline to produce green hydrogen." The expert said.
Zhao Yue, senior engineer of East China Survey, Design and Research Institute Co., Ltd. of Power China Construction Group, believes that the lack of steady development rhythm is the main problem facing the industry at present. First of all, is the demand for offshore PV so urgent? The reason for the rapid development of offshore wind power is that offshore wind energy resources are larger than onshore wind energy resources, and the wind turbine output is more, but the lighting conditions on land and offshore at the same latitude are almost the same, and the construction and maintenance costs of the latter are many times higher than the former. Secondly, can we objectively face the technical difficulties of offshore PV? Many people think that offshore photovoltaics are consistent with onshore or shoal photovoltaics, which is a misunderstanding that needs to be carefully examined from a rigorous perspective and attitude of Marine engineering, and now the accidents in this project have proved this.
In response to the "photovoltaic road" event that triggered external attention, Zhao Yue believes that foreign technology needs to be combined with the domestic Marine environment to do further adaptation research, and gradually establish industry norms. At present, many domestic universities and research institutions are also trying to contact such projects, but whether it is in structure, materials or technology, there is an urgent need for cooperation and joint response from all parties in the industry chain in order to effectively help the development of the offshore photovoltaic industry.
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