When deciding where wind turbines should be placed, there are many concerns including, the best location, the optimal height, environmental concerns, and cost. Even though wind energy is clean, renewable energy resource there are still environmental concerns. Wind turbines have been known to kill birds. Also they make irritating noise when spinning. These problems can be reduced however if a location relatively far from popular areas is chosen. Also wind energy is significantly more expensive than fossil fuels. With time and development in the technology the cost could be reduced. This topic is discussed on the Future of Wind Power page.
The aesthetics of wind turbines as also been a question, particularly in Massachusetts where the Cape Wind Project is located. This is discussed later on this page.
Turbine Height
Standard turbine height is 50 m. Since there’s more wind at higher altitudes the wind turbine height ranges from 50 m to about 100 m.
But how does height impact the power output? The following equation shows the relationship between tower height and velocity.
(V/Vo) = (H/Ho)^a where a is coefficient of friction is the turbine, Ho is the height from the bottom of the turbine to ground, H is the height from the center of the turbine to ground, V is wind speed at H, and Vo is wind speed at Ho. Since P is proportional to v^3 the resulting equation is (H/Ho)^3a=(P/Po). The coefficient of friction increases with rougher terrain and which in turn increase the power significantly. Therefore, higher turbines are ideal. The trade of is the higher turbine is more expensive.
Cape Wind Project
The map below shows the areas of the US that have winds at 50 m above ground that can produce usable amounts of electric energy.
According to the map the fastest winds occur in between the Midwest and West Coast. If you look at the East Coast you will notice a tiny locating offshore Massachusetts with very high wind. Sitting nearly 5 miles from shore will be the site of America’s first offshore wind farm and construction is expected to begin in 2013. It is expected to produce energy about 86% of the time and the turbine cut-in speed will be 8m/s.
This project is an interesting one because in the years leading up to its approval the residents of Nantucket sound were concerned with the location of the wind farm. Many said that the wind farm would ruin the view and decrease property value. This is why it has taken so long for approval. Click here for more information and updates on the Cape Wind Project.
Sources
http://windeis.anl.gov/guide/basics/index.cfm
http://www.capewind.org/index.php
Edited: 11/27/12 by Andria Young, young10@illinois.edu
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