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Announcing the AEE Solar 2007-2008

Renewable Energy Design Guide & Catalog

Our 2007-2008 Renewable Energy Design Guide & Catalog has been completely updated, redesigned and produced in full color for the first time; 192 pages displaying thousands of renewable energy products -systems, equipment, components and parts.

Retail End-Users

Contact us to find an AEE Solar dealer/installer near you!

When you join our network of AEE Solar wholesale customers - renewable energy dealers and installers, grid-tie system integrators, online solar dealers, specialty resellers, and government and industrial remote power users -you can utilize this invaluable resource in two ways. You can use it as:

• Our Printed Catalog - A well-organized, handy reference to the most extensive inventory in the industry, providing all the latest specs and information, suggested retail prices, expert advice on system design and installation, helpful tips on product usage, and more.

• YOUR Printed Catalog! As an authorized AEE Solar reseller,you can order multiple catalogs with a special cover that has space for your company's name and logo instead of ours, thereby making the industry's leading catalog your own powerful sales tool!

We'll send you a free copy when you apply to become an AEE Solar customer. Apply online, or download a mail-in form from our site.

See our new website - with online ordering!

constant speed. These measures will help increase your city fuel economy (as well as increase the time between brake replacements). Likewise, mountain driving offers a number of challenges to fuel economy. Here again, coasting (when possible) and driving slower (when no one is tailing you) will save fuel and reduce pollution.

Another means of saving fuel is to consider carpooling. If you put four people in one car, you'll cut pollution and fuel consumption by about 75 percent compared to four people driving their individual cars. Now that's impressive!

Dominic Crea • Institute for Sustainable Energy & Education

How Tall?

I hear a lot of talk about wind generators needing tall towers. How do I decide what's tall enough? Is there such a thing as too tall?

Jon Powell • Duluth, Minnesota

Although there are several factors that affect tower height, your choice will most likely be a compromise between energy production and economics.

Proper tower height is essential for two reasons: Turbulent wind is not only a poor quality fuel, but it dramatically increases wear and tear on the turbine and tower. To provide the turbine with high quality "fuel," the tower must be tall enough to be well above the turbulence layer created by obstructions such as buildings and vegetation. The wind is stronger up there, and smoother. Ground drag created by obstructions and the ground itself reduces the energy available in the wind. To minimize ground drag, we need altitude. Put simply, wind speed increases with height.

Minimum guidelines for tower height require the turbine rotor to be a minimum of 30 feet higher than obstructions within 500 feet. You should go even taller if the obstructions are young trees that will continue to grow. Finding the average annual wind speed at your site at a given tower height is a bit more difficult, but I would highly recommend trying to determine or at least estimate it, starting with regional wind energy consultants and dealers.

Now for the economics. Once I know the minimum tower height needed to get above the turbulence, I let the turbine and the customer's budget help determine the maximum tower height. I look at the cost of the turbine, its estimated energy production at various tower heights, and the cost of the towers.

The following example uses wind data from my hilltop in western New York, a Bergey Excel-S grid-tie turbine, and three different heights of guyed lattice tower:

Sample Tower Height

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