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September 2009

Turbines must meet certification requirements

NREL and AWEA collaborate with industry professionals to align international wind-turbine certifications with U.S. regulations, both local and national.

Almost all large wind turbines available on the market today have been certified by an international certification body through a comprehensive design evaluation, testing, and quality-manufacturing review process. When these turbines are introduced into the U.S. market they must also satisfy local requirements for items such as structural and electrical permits. As offshore wind plants […]
Sandy Butterfield

A look at preventive maintenance

The generator is the heart of the windmill power generation system, so developing an ongoing maintenance program will help protect your investment.

With the increasing investment into the development of wind farms, preventive maintenance takes on an important role in ensuring the reliability and cost-effectiveness of this energy business. The reliable operation of the drive train requires the preventive maintenance of key components such as generators and gearboxes. The generator is the heart of the windmill power […]
Garnik Haghverdi, V. Anton Soldo, Sumit Singhal

Micropiles are versatile foundation systems

Micropiles are versatile enough to function either as a new foundation, or as a remedial solution for an existing foundation. This installment provides insights.

Many deep foundation systems are available for support of wind turbine tower foundations, including driven piles, drilled caissons, augercast piles, and micropiles. Of these systems only micropiles are versatile enough to function either as a new foundation for a planned structure, or as a remedial solution for an existing foundation. Also known as minipiles, pin […]
James D. Hussin

Making sense of small wind

For those with creative minds and spirits, small wind offers an amazing opportunity for designing systems to fulfill a growing market demand.

In the small wind industry you will often encounter the sentiment that you should buy the biggest tower you can afford in order to maximize the total energy harvested from the system. This is true, in a sense, and I personally believe that every homeowner with enough space and wind should be allowed to erect […]
Michael Miller

Understanding the entitlement process with small wind

The more you know about how to go about winning planning approvals and assisting your customers, the more successful your small-wind projects will be.

There are over 25,000 individual planning commissions in the United States, and each has the potential to promote the adoption of regulations hostile to the growth of distributed generation small wind systems. In order to effectively market home and commercial small wind systems, installers need to understand the entitlement process and be able to guide […]
Michael Miller

July 2009

Ground improvement techniques for turbine sites

Performed properly, a mat foundation bearing on aggregate piers is an efficient and economical alternative to traditional deep foundation systems.

When the geotechnical exploration at a planned wind turbine tower location reveals that the subsurface conditions are weak and compressible, a deep foundation system consisting of a mono-pole or drilled/driven piles is often recommended by the geotechnical engineer. However, often the poor soils can be strengthened and stiffened economically to enable the tower to be […]
James D. Hussin

Maintaining gearbox oil properly

Lubrication quality is a key driver for gearbox reliability in wind turbines. This installment focuses on choosing the best type and how to maintain it.

Oil is a key life-cycle driver of a gearbox, and proper maintenance is important. The primary purpose of oil is to provide lubrication and protection to rotating mechanical parts such as gears and bearings, and it’s used as a coolant for the gearbox as well. Each of these components’ life-cycle design is based on certain […]
Shawn Doner, Parthiv Amin

Making sure the gearbox stays realiable

Gearbox designers and manufacturers follow stringent standards for designing and building gearboxes, but failures persist. This group is seeking a solution.

Gearbox reliability is a crucial issue for the wind energy industry. The gearbox and its supporting components (i.e. shafts, generator, brakes, and lubrication system) account for roughly 30 percent of the turbine’s capital cost, excluding foundations and site infrastructure, and the gearbox is the most expensive component to repair or replace. Recurrent gearbox failures have […]
Kathleen O’Dell

May 2009

Dealing with the gearbox

Ideally, gearboxes would run forever with no downtime, but repairs are required in the real world. Ask the following questions for improved outcomes.

As you know, the gearbox is a critical component of the wind turbine drivetrain. Should you encounter a problem with this unit, what should you do? Who can handle the repairs, what will they cost, and how long will it be down? All are valid questions, but one of the most important is whether the […]
Eckart Bodenbach, P.E.

Foundation problems and their solutions

No structure can remain standing without a solid foundation. Read on for a primer in foundation types and ground-preparation techniques.

Foundations have been a critical aspect of wind turbine tower design since the earliest days of the industry. Many early towers experienced foundation problems since the unique loading associated with these structures was not yet fully understood. As towers become taller, efficient foundation design is an increasingly significant component of the overall profitability of wind […]
James D. Hussin

Inside NREL’s National Wind Technology Center

You’ll be amazed by the wind-industry support capabilities of NREL’s wind energy research facility, at the foot of the Colorado Rockies.

“You make ‘em, we’ll break ‘em” could be the motto of the National Renewable Energy Laboratory’s (NREL’s) National Wind Technology Center (NWTC). Located just south of Boulder, Colorado, it is the U.S. Department of Energy’s premier wind energy research facility. At the NWTC researchers work with industry partners, testing full-scale wind turbines and their components […]
Kathleen O’Dell