Exploring offshore wind energy storage methods

my country is rich in offshore wind energy resources, with a continental coastline of more than 18,000 kilometers and a usable sea area of ​​more than 3 million square kilometers, making it one of the countries with the richest offshore wind energy resources in the world. Offshore wind power is located in the southeast coast, close to the power load center, and land resources are scarce. Offshore wind power can alleviate these problems. In order to seize the opportunity, major domestic energy companies have "snatched land" and almost divided up all the sea areas suitable for offshore wind power in my country. China's offshore wind power market is booming.

Offshore wind power, like onshore wind power, is volatile, intermittent and irregular, which makes the contribution rate of wind power to the power grid less than 10%. At 10%, it will bring hidden dangers to the operation of the power grid. Offshore wind power also has the problem of "wind abandonment", and the problem of offshore wind power energy storage needs to be solved. The energy storage technology of onshore wind power is constantly improving, and a number of new energy storage technologies are being developed, such as: wind power solid energy storage devices, solar energy solid energy storage devices and other new energy storage technologies, which have been developed one after another, greatly enriching the energy storage methods of onshore wind power, but offshore wind power energy storage is still blank.

At present, the more advanced one is the offshore wind power pumped storage system developed by the Fraunhofer Institute in Germany. This system uses the pumped storage power station located on the seabed to store energy. It puts a hollow ball into deep water, and uses the seawater pressure in deep water to store energy. When energy storage is needed, electricity is used to pump water from the ball. When energy needs to be released, the water flows through the turbine and returns to the ball, thereby driving the generator to generate electricity. Although this technology solves the problem of offshore wind power generation and energy storage, it has defects. First, it has a narrow scope of application. It is only suitable for deep water areas because the deeper the water, the greater the pressure; second, it requires multiple conversions and has low efficiency. It first converts wind energy into electrical energy, then electrical energy into mechanical energy to pump water, and then water energy into electrical energy, which is very inefficient.

Recently, the "buoyancy and gravity composite energy storage offshore wind power generation system" developed by Zhang Zhanhai in Chengde City, Hebei Province has been successful. It mainly uses the buoyancy of seawater to store energy. When there is wind at sea and the power grid is at peak power consumption, the wind power system works normally and the fan drives the engine to generate electricity; when there is wind at sea and the power grid is at low power consumption, power is transmitted through the system to press the buoy into the seawater, and at the same time, the bucket filled with seawater is raised out of the sea surface, using the buoyancy and gravity of seawater to store power; when there is no wind at sea and the power grid is at peak power consumption, the buoyancy of the seawater generates power upward, and at the same time, the bucket generates power downward due to the gravity of the seawater, releasing the stored energy.

Its benefit lies in that it adapts to local conditions and takes advantage of the fact that offshore wind power is located in abundant seawater. The seawater can generate buoyancy upwards and gravity downwards. By effectively utilizing these two forces, energy storage is achieved. It is suitable for both deep and shallow waters. At the same time, energy is directly converted with high efficiency.

The successful research and development of this offshore wind power energy storage technology can not only fill the gap in offshore wind power energy storage technology, but can effectively solve the problem of offshore wind power energy storage and will promote the vigorous development of offshore wind power.