By Amy Berry

Traditional Wind Farm Site Disadvantages Are Actually Advantages in Urban Settings

For most who hear the words “wind power” the mind conjures up images of towering white propellers in a wide open rural setting. These large propeller turbines, also known as horizontal axis wind turbines (HAWTs), are the standard in the large wind industry due to their excellent efficiency in converting wind to power. However, what makes them ideal for large scale wind farms (large and remote open spaces with consistent wind direction) does not necessarily make them a great fit for urban sites. In fact, the traditional limitations of vertical axis wind turbine (VAWT) technology for wind farm applications can actually turn into advantages for more urban locations.   Increasingly, homeowners and small businesses are considering VAWTs to help overcome the challenges associated with many small wind sites.

By Sustainable Business – Matter Network

The U.S. market for small wind turbines–those with capacities of 100 kilowatts (kW) and less–grew 78% in 2008, according to the American Wind Energy Association (AWEA).

With a total of 17.3 megawatts (MW) of new installed capacity, consumer demand for clean energy options is on the rise, the Association said.

U.S. manufacturers sold about half of all small wind turbines installed worldwide last year. U.S. market share amounted to $77 million of the $156 million global total. (Worldwide, about 38.7 MW of new small wind capacity was installed in 2008.)

“The U.S. wind industry is a growing bright spot in our domestic economy, and the small wind sector is no exception,” said AWEA CEO Denise Bode. “Strong federal policies like the federal investment tax credit for small wind are critical to future growth, just as adoption of a federal renewable electricity standard (RES) is essential to growth in the utility-scale market.”

Companies like AVN Energy, a Danish manufacturer of wind-power equipment, are creating the technology which now provides 20% of Denmark’s electricity production. AVN co-operated with The Trelleborg Group’s Sealing Solutions to develop seals for their wind power actuators. Trelleborg’s reporter, Donna Guinivan, visited AVN’s plant, Silkeborg, Denmark, to get the full story on this and the future of wind power in general:

New AeroCam Turbine Turns Almost Any Location Into an Affordable Source of Wind Power Generation

Renewable energy from the wind, which previously could only be generated in restricted geographic locations – typically off-shore or in remote rural areas – can now be made available almost anywhere, including urban environments, with the introduction of the AeroCam wind turbine.

The AeroCam, developed by BroadStar Wind Systems, was designed and patented for commercial applications. With its parallel rotor blades, not only does it look radically different from conventional propeller designs, but also can be manufactured, transported, installed and maintained at lower cost.

SCHENECTADY, N.Y. – Renewable Energy Systems (RES) Americas Inc. of Austin, Texas, one of the leading wind developers in North America, has signed agreements exceeding $700 million to receive GE Energy 1.5-megawatt wind turbines for projects in 2009 and 2010.

GE Energy will supply RES with nearly 500 megawatts of new wind energy capacity, and will provide commissioning and operations services as well as maintenance support. “Throughout the United States we continue to witness strong interest in the production of cleaner, wind-generated electricity,” said Victor Abate, vice president-renewables for GE Energy. “We are pleased that RES has selected our well-proven, 1.5-megawatt technology to help the company reach its build-out goals for the years ahead.”

Aiming laser at model windmills shows how clean power source can stir up the atmosphere

Using smoke, laser light, model airplane propellers and a campus wind tunnel, a team led by Johns Hopkins University researchers is trying to solve the airflow mysteries that surround wind turbines, an increasingly popular source of “green” energy. The National Science Foundation recently awarded the team a three-year, $321,000 grant to support the project.

The rise in oil prices and a growing demand for energy from non-polluting sources has led to a global boom in construction of tall wind turbines that convert the power of moving air into electricity. The technology of these devices has improved dramatically in recent years, making wind energy more attractive. For example, Denmark is able to produce about 20 percent of its electric energy through wind turbines. But important questions remain: Could large wind farms, whipping up the air with massive whirling blades, alter local weather conditions? Could changing the arrangement of these turbines lead to even more efficient power production? The researchers from Johns Hopkins and Rensselaer Polytechnic Institute hope their work will help answer such questions.

“With diameters spanning up to 100 meters across, these wind turbines are the largest rotating machines ever built,” said research team leader Charles Meneveau, a turbulence expert in Johns Hopkins’ Whiting School of Engineering. “There’s been a lot of research done on wind turbine blade aerodynamics, but few people have looked at the way these machines interact with the turbulent wind conditions around them. By studying the airflow around small, scale-model windmills in the lab, we can develop computer models that tell us more about what’s happening in the atmosphere at full-size wind farms.”

To collect data for such models, Meneveau’s team is conducting experiments in a campus wind tunnel. The tunnel uses a large fan to generate a stream of air moving at about 40 mph. Before it enters the testing area, the air passes through an “active grid,” a curtain of perforated plates that rotate randomly and create turbulence so that air currents in the tunnel more closely resemble real-life wind conditions. The air currents then pass through a series of small model airplane propellers mounted atop posts, mimicking an array of full-size wind turbines.