Compared with land wind power, the environment and land conditions of offshore and intertidal wind turbines are completely different, and the offshore wind power technology is far more complicated than land wind power. In the process of designing and building offshore wind farms, we will have to consider the impact of harsh natural and environmental conditions at sea. Such as salt spray corrosion, wave load, sea ice collision, typhoon damage and other restrictive factors.
Offshore wind power construction is different from other projects, involving a series of issues such as the division of sea functions, the laying of navigation channels and cables, the design, construction and installation of offshore wind turbines, grid connection, environmental protection and even national defense security.
Compared with onshore wind power, offshore wind power is far from the coast. Under the influence of harsh marine environment, the failure of vulnerable parts such as bolts is accelerated, and the failure rate of electromechanical system is greatly increased, which leads to the accelerated maintenance frequency. At the same time, special equipment and transportation tools are needed for operation and maintenance, which leads to a great increase in maintenance expenditure.
Then, since the conditions of offshore wind power are not as good as those on land, why should we develop offshore wind power?
Specifically, the advantages of offshore wind power generation over land are obvious:
1. The wind at sea is very stable.
Whether the fan works well depends on the wind. The wind at sea is generally stronger than that on land. The fluctuation of land topography plays an important role in slowing down the ground wind speed, so the land fans are set very high to take advantage of the high-altitude wind. However, due to the terrain problem, the wind speed at different heights on the land is very different, which leads to a large wind shear (vertical wind speed change), which makes the wind turbine unbalanced up and down, which leads to the easy damage of the transmission system. There is no such problem at sea. The sea level is generally flat, the wind has no resistance, the average wind speed is high, and the wind shear is less than that of land. In addition, the frequency of wind direction change at sea is lower than that on land, so the wind energy at sea is very stable.
2. The utilization rate of the fan is higher.
The power generation of wind turbines is directly proportional to the cubic power of wind speed, and the wind speed at sea is about 20% higher than that on land, so the annual power generation of wind turbines at sea can be 70% higher than that on land under the same power generation. If the annual power generation utilization hours of onshore wind turbines are 2,000 hours, the offshore wind turbines can reach more than 3,000 hours.
3. The installed capacity of single machine is large.
The greater the power generation capacity of a single fan, the more cleaning area and energy used in the same place, that is, the more fully utilized resources. The larger the capacity of a single machine, the larger the generator and the longer the blades. The biggest problem on land is traffic. It is difficult to transport blades nearly 100 meters long on land (even tens of meters when divided into two sections), but this problem does not exist at sea. Just pull them by boat. For example, Youshi Electric participated in the onshore wind turbine project with a maximum capacity of 2.5MW, while the offshore wind turbine in Pingwan, Hunan started directly at 5MW. In China market, a 5MW wind turbine can get more than 400 million yuan of electricity from the air without consuming any energy.
4. Do not occupy land and disturb people.
Land resources are scarce, the red line of cultivated land cannot be moved, forest land cannot be built, and so on. With the development of onshore wind power, there are fewer and fewer places with good onshore wind resources, and the noise of wind turbines has a greater impact on residents and animals. Some research institutions have specially studied the influence of vermicelli on wild ducks. However, these problems do not exist in offshore wind farms. China is a maritime power with a coastline of over 6,543,800 km, ranking fourth in the world.
5. Close to the electric load
A large number of wind farms have been built in the vast northwest of China, and these wind farms will undoubtedly be transported to the power load center in the southeast coast through UHV and UHV lines, with a distance of more than two or three kilometers. However, offshore wind farms are basically built in coastal areas of one or two hundred kilometers, which are close to the load center and windy all the year round, which is very suitable for the needs of power load centers.
Based on the above advantages, building offshore wind farms is the development trend. Although offshore wind power is still in its infancy, especially in China, all countries are developing offshore wind power in general. In the future global energy supply system, offshore wind power will have a broader prospect than onshore wind power.