How Long Are Wind Turbine Blades?

When there is a difference in air pressure along the sides of a blade, lift and drag forces are produced, which is how wind turbines produce power. The wind turbine spins the rotor and produces electricity when the lift force is greater than the drag.

But how long are the blades of a wind turbine? In this post, we will discuss the issue and other pertinent issues.

Further Reading: Wind Power Plant: a Complete Guide

How Long Are Wind Turbine Blades?

Only 26 feet long and made of fiberglass and resin forty years ago, wind turbine blades. Today, blades can be 351 feet long, longer than the Statue of Liberty, and generate 15,000 kW of power.

Due to their higher strength qualities, modern blades made of carbon fiber can withstand more stress. The design of the blade tip has been improved aerodynamically, which also results in less noise.

The Siemens Gamesa SG 14-222 DD offshore wind turbine prototype, which is undergoing testing in Denmark, is the biggest and most potent wind turbine in the world. This can provide 18,000 European homes with electricity each year thanks to its 15 MW capacity and 222-meter rotor.

The swept area is 39,000 m² (translating to a larger volume of air and more mass to move) with each blade being 108 meters (354 feet). This flagship model is expected to go on sale in 2024, with an installation date set for later that year, in 2022. It is roughly the length of an entire football field or 1.5 times the wingspan of a Boeing 747 aircraft.

The average swept area of wind turbines has increased by half since 2009, while the length of the blades has grown by 20%. More wind is captured by larger swept areas, which calls for more flexibility in the blades so they can bend and deflect the wind.

Why Has Turbine Blade Length Doubled?

Longer blades make turbines more effective, but they also put more mechanical stress on the structure, necessitating lighter materials and better engineering.

Due to advancements in the fabrication process, the size of wind turbine blades has doubled since the 1980s.

Polyurethane can reduce the amount of material needed for a blade by 10%, making them lighter and more wind-resistant. Long wind turbine blades can be produced more easily thanks to polyurethane’s superior mechanical and fatigue properties over epoxy.

As blades account for 30% of the cost of a wind turbine due to complex composite molds, polyurethane’s lower cost is essential for reducing the Levelized cost of energy (LCOE).

This results in smaller wind farms that occupy less space while housing more potent wind turbines because of larger wind turbine blades. Having one very powerful wind turbine rather than three smaller ones with less maintenance and material costs is also more cost-effective. Since there will be fewer wind turbines overall, fewer blades will end up in landfills, making wind energy more sustainable.

Although the rotor diameter and tower height have no predetermined ideal ratio, on average, the rotor diameter and tower height are equal. Offshore, the blades are typically larger than onshore and more than half the height of the tower.

For instance, the 107-meter blades of the 14 MW GE Haliade-X wind turbine, which is the largest wind turbine currently in production, occupy 80% of the tower’s height. Some of the biggest parts of a machine ever constructed are these blades.

These massive blades don’t require strong winds to move; in fact, their low rotational inertia maintains momentum even when the wind speed has significantly decreased.

What Sizes Are Wind Turbines?

Offshore wind, distributed wind, and utility wind are the three types of wind energy that are harvested. The size of the needed wind turbines will be determined by the area that needs to be powered.

For horizontal axis wind turbines (HAWT), the wind must be aligned with the turbine for proper setup. Let’s look at the three sizing differences in wind turbines:

120-215 Feet Towers

Typically, these towers produce less than 100kW, which is regarded as small and primarily for household needs. Additionally, they require less land and financial investment than larger wind turbines, which makes them more popular.

These sizes are more profitable and economical while still satisfying customer coverage requirements. This size wind turbine may be suitable for you if you live off the grid or in a rural area.

215-275 Feet Towers

These typical-sized towers produce between 100kW and 1MW. In the United States, this is the typical size. The height range is just tall enough to generate electricity for a neighborhood. The majority of locations have strong winds that are high above the ground, which makes this clean energy harvesting possible.

280 Feet Or More Towers

The largest and tallest group of wind turbines is located at this level. The largest towers produce 7.8 to 8.8MW on average. Most often, offshore wind turbines require an enormous size. Several megawatts of power is generated on a large scale and distributed over a wider area.

How a Wind Turbine Works?

The rotor blades of a wind turbine, which operate similarly to an airplane wing or a helicopter rotor blade, convert wind energy into electricity using aerodynamic force. The air pressure on one side of the blade decreases as the wind passes across it.

Both lift and drag are produced by the difference in air pressure between the blade’s two sides. The rotor spins because the lift force is greater than the drag force.

The connection between the rotor and the generator can be made directly (in the case of a direct drive turbine) or through a gearbox, which speeds up rotation and enables a physically smaller generator. Electricity is produced when an engine’s rotation is converted into aerodynamic force.

FAQs