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4 Wind Turbine Upgrades that Improve Efficiency

4 Wind Turbine Upgrades that Improve Efficiency

| John Meaney, Regional Sales Manager

It is astounding to see wind turbine technology the way it is now, compared to what it was just a decade ago. The production output has grown eight times from what it was in 2007. Wind turbines continue to get larger and more efficient each year with the goal of increasing wind energy’s competitiveness. Here are four areas where wind turbines have been evolving to achieve higher performance.

Longer blades
Wind turbine blades extend to lengths of 50 meters (164 feet). Wind farms get more efficiency out of longer blades because they sweep up more wind energy, resulting in improved economics for the wind farm.

When the wind spins the turbine blades, the blades rotate the gearbox, the gearbox turns the generator, and the generator converts the wind energy into electricity. The electricity is sent down into the transmission lines to power our homes and businesses. Longer blades makes this process more efficient. Investing in longer blades makes business sense for a new wind farm looking to optimize profitability.

Of course, when the blades are longer, they are heavier. Turbine manufacturers began building with high strength composite materials, such as carbon fiber and epoxies, to make the blades lighter and to increase their velocity.

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Taller wind turbines
Taller towers, many of which reach 100 meters (328 feet) or more, accommodate longer blades. New wind farms typically invest in larger turbines for maximum operational efficiency. Established wind farms with smaller turbines typically run the turbines to end-of-life before replacing them with the newest models.

Increased capacity
The capacity of the wind turbine is increasing with the latest models. A 1.7 megawatt turbine on the market, compared to its 1.5 megawatt predecessor, has a 24% increase in annual energy production, according to manufacturer literature. The average turbine capacity being deployed has increased significantly in the last ten years. Offshore wind turbines have capacities of six to twelve megawatts to capture the higher amounts of consistent wind over the ocean.

While renewable energy generation has proliferated, the success of new wind farms really depends on demand. During the summertime, wind turbines often reach their maximum generation capacity since there is high demand for electricity. In the winter, there is less demand. Wind farm operators consider these factors when investing in new technology.

Energy storage upgrades
As turbines get larger, they need more power for the emergency pitch control system, which rotates the blades out of the wind during an emergency shut-down situation. The pitch system is critical for protecting the wind turbine from severe damage in the case of high wind speeds that could spin the blades out of control.

In the US, most turbines with electric pitch control systems have been designed with lead-acid batteries for backup energy storage. The batteries provide the energy necessary to pitch the blades when grid power is down, and they recharge when grid power becomes available again.

While batteries are useful for many energy storage applications, wind farms experience many hours per week of turbine downtime due to the variety of maintenance tasks related to battery-based pitch control systems.

Batteries tend to perform poorly in very hot or cold temperatures and often do not serve their full lifetime due to demanding operational conditions. Premature failure requires wind technicians to shut down the turbines and climb to the nacelle with new batteries to make replacements. Batteries also require expensive chargers and in some cases take 20 to 30 minutes to recharge.

All of this matters when every hour that the turbine isn’t running equates to lost generation dollars.

Ultracapacitors have proven to be a more effective energy storage alternative to batteries for pitch control, providing increased operational efficiency. They are currently installed in thousands of onshore and offshore wind turbines. The switch from batteries to ultracapacitors for pitch control has accelerated significantly in several countries due to their reliability, minimal maintenance requirements, and the valuable time they save wind farm site personnel in terms of maintenance efforts as well as increased revenue hours.

The ultracapacitor (or supercapacitor) is an electrostatic device that unlike the battery is less susceptible to cold and hot temperatures and has the special ability to deliver high power in fast bursts and recharge rapidly. Many wind farms in the US have begun to retrofit battery-based systems with ultracapacitors to gain those same advantages.

Wind turbines are becoming more efficient and profitable with upgrades such as longer blades, higher generation capacities, and streamlining energy storage technologies. The past 10 years have shown tremendous progress in terms of number of wind farms, employment and technology advances. It is likely that the next 10 years will deliver much of the same growth.

Chuck Cook, senior field applications engineer, contributed to this post.

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Mike EverettJohn Meaney
Regional Sales Manager, Southeast U.S., Mexico and South America
About this author

John Meaney joined Maxwell Technologies as regional sales manager for the Southeast U.S., Mexico and South America in August 2010. Prior to joining Maxwell, he worked in the wireless and computer industries holding sales management and general management positions at D-link, Gateway, Toshiba, Panasonic and IBM. He holds a B.A. in economics from the University of Notre Dame and M.B.A.s in finance and marketing from Long Island University and Fairleigh Dickenson University, respectively.

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