Wind Power Generation Q&A

Ｑ１How big is a small windmill?

A windmill with a diameter of 7 m or less (a wind-swept area of 40 m2 or less) or a windmill output of 20 kW or less is called a small windmill. In particular, those with a power output of less than 1 kW are called micro windmills.

Ｑ２What can a small windmill be used for?

A small windmill can obtain energy independently, so they can be used in a variety of applications, such as power sources for mountain huts and farmlands, ships, wireless devices, LED display panels for advertising, and submersible electric pumps. In urban areas, it can be used as a night light, emergency power source, park, and, of course, home power.

Ｑ３What kind of windmills are there? Which windmill is better?

Windmills are classified into vertical-axis winmills and horizontal-axis windmills, depending on the direction of wind on the windmill axix. Each type has its advantages and disadvantages. Vertical-axis windmills can receive wind from anywhere in 360 degrees, but it is generally said that the amount of energy they can receive from the wind is small. Horizontal-axis windmills can obtain a large amount of energy from the swept area, but directional control is important to receive the wind from the front.

Ｑ４What should we pay attention to when installing a small windmill?

Please avoid places where people come close. Choose the place that is well-ventilated and free of obstructions. We do not recommend using it on the balcony of an apartment building, as there are many unfavorable conditions such as safety, noise, and wind conditions.

Ｑ５How do we handle a small windmill against strong winds?

Each windmill has its own blade rotation limit and wind resistance. If it reaches the upper limit of the rotation, it may cause failure such as damage to the generator or blades, so the control is implemented to prevent this.

Ｑ６How can we check the power generation performance of a windmill?

Most of the performance shown in the manufacturer's catalog is the data obtained from the wind tunnel experiments, so the amount of power generated by the natural wind when installed tends to be lower than in the catalog. For this reason, we recommend that manufacturers confirm the power generation data from natural winds. Unlike the wind tunnel, the direction of the wind changes and the natural wind blows strongly or weakly therefore even if the wind tunnel test data is good, it may not be obtained in the natural wind.

Ｑ７How does a windmill work?

Basically, the structure of the motor is reversed. A motor uses electricity to rotate its shaft (power), but a windmill rotates its shaft using wind power to obtain electricity. Since the generated electricity is alternating current, it is rectified to convert it to direct current. After that, the battery is charged or boosted, converted to alternating current, and used as a power source.

Ｑ８Can the generated electricity be used as a power source for home appliances?

The energy obtained from the windmill cannot be used directly as a power source for a home. The power obtained from the blades is transmitted to the shaft of the generator and converted into electricity. It is rectified once and then used as a power source. How to use it as a power supply is ...
① Independent Power Supply
The generated electricity is first stored in a battery, converted to AC 100V by an inverter, and supplied to electrical equipment. If the battery voltage drops below the lower limit, the power supply will stop.
② Switching Power Supply
The independent power supply reduces the power supply when the battery voltage drops, but the switching power supply automatically switches to the commercial power supply of the power company when the power supply drops. However, when switching, it will stop momentarily.
③ Grid Connection
A system that allows you to buy and sell electricity by connecting to the commercial power supply of an electric power company. It is the same system as a home solar system.

Ｑ９What is the average annual power consumption of a general household?

The average annual power consumption of a general household is estimated at approximately 4,500 kWh (approximately 370 kWh/month). It is a good idea to check the electricity tariff that will be delivered to your home.

Ｑ１０Is it a good combination with solar power generation?

The hours of sunshine are longer in summer than in winter. The wind tends to blow seasonally in winter rather than in summer. Therefore, the advantages and disadvantages of sunshine and wind conditions change between summer and winter, so we can expect relatively stable power generation by combining wind power generation and photovoltaic power generation.