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Wind power generation utilizes the strength of wind to generate power by spinning turbines. Since wind power is considered clean energy that does not emit CO2, its role is critically important in preserving the future of the environment.
How does wind blow in the first place? Let's first consider what we learned in elementary school science classes. The answer includes the air and the sun.
Cycles of air heated by the sun and cold air cause air to move. Heated air becomes an updraft that causes a vacuum in the surrounding air, creating low pressure.
Meanwhile, cold air becomes a downdraft, forcing air into the surrounding area, creating high pressure. When air flows from an area with higher pressure than that with lower pressure--This is wind. An important difference between the pressure increases the amount of air flow, creating stronger wind power. Air flows from high pressure areas to low pressure areas.
Wind power generation is designed to generate power using the natural force of wind. The fact that wind power is a sustainable form of energy differentiates it from non-reusable forms of energy.
Now, let's take a look at the structure of a wind turbine, using the 2,000kW Wind Power Generation System co-developed by Hitachi and Fuji Heavy Industries as an example.
The most noticeable feature is the propeller-type blade. Because the blade receives wind and converts it into a rotary motion, its shape and angle are keyed to rotate even with moderate wind.
The part standing upright from the ground to the sky is called the tower. A cone-shaped steel tower is generally used, as it is of a lighter weight compared to a concrete tower. This is tube-shaped and has power cables, control optical fibers and so on inside.
The structural object on the top of tower is called a nacelle. The nacelle contains a speed-up gearbox and power generator, which can be called the “heart” of the wind power generation system.
What is surprising is the size of the wind turbine, with its 60 or 80-meter high tower and 40-meter-long blades. This also proves that only one unit can generate a great deal of power. Since an industrial motor (induction motor) was the first product of Hitachi, Ltd., the company is taking advantage of its know how of 'Monozukuri (manufacturing)' that it has cultivated over the 100 years since its inception in 1910 for the development of this product.
The share of wind power generation in electricity is only 0.1% in Japan. This is because the wind conditions are comparatively unstable in Japan. Since, the speed of wind, which is normally weak, the erratic direction and speed of the wind due to typhoons and seasonal winds and the complex topography exacerbate this tendency.
The 'Downwind rotor system' that makes wind blow from behind the rotor is used to deal with climates not only overseas but also in Japan in which the direction and power of the wind are erratic. This allows a wind turbine to catch wind blowing upwards along the terrain efficiently, even if it is set on a mountain or hilly terrain. In addition, the blades constantly move downwind and can fend off gusts from typhoon.
The wind turbine contains a Hitachi power generator that enables constant and stable power generation responding to changes in air volume for its power generation system. Also, an insulated gate bipolar transistor (IGBT) has been newly developed as the main circuit to allow for highly efficient and stable operations, enabling higher voltage and reduction of power loss.
Thus, the 2,000kW Wind Power Generation System is the culmination of the thorough pursuit of an ideal wind turbine, which is able to respond to changes in the direction and speed of wind firmly resulting in creating cleaner energy.
The Hitachi Group views the 2000kW Wind Power Generation System as one of the ways we can achieve our Environmental Vision 2025, with a goal of helping to reduce annual CO2 emissions by 100 million tons by 2025 through our products and services.