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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 remember 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 2MW Wind Power Generation System developed by Hitachi.
The most noticeable component 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 conical steel tower is generally used, as it is of a lighter weight compared to a concrete tower. This is tubular and has power cables, control optical fibers and so on inside.
The structure installed on the top of tower is called a nacelle. The nacelle contains a step-up gearbox and generator, which can be called the “heart” of the wind power generation system.
The height of taller 2MW-class towers are approximately 80 meters, with each blade approximately 40 meters long. The size of the newly developed 5MW-class wind turbine towers will astound you, standing at approximately 90 meters tall with 66.5-meter-long blades.
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 100 years since its inception in 1910 for the development of this product.
One of the reasons why wind power generation is not widely used in Japan 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 Tyhoons and seasonal winds and the complex topography exacerbate this tendency.
The 'Downwind Rotor' that makes blades position leeward of the tower 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 up-blow wind along the slope of terrain efficiently, even if it is installed on a mountain or hilly terrain. In addition, the blades constantly move downwind and can fend off cross wind 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 developed as the main circuit to allow for highly efficient,reliabile and stable operations, enabling reduction of power loss.
Thus, Hitachi’s 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 2MW 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.