Environmental Engineering Reference
In-Depth Information
FIGURE SB2.1.3
Power line right of way (ROW).
With regard to transmission siting, the remote location of much of the utility-scale
wind power capacity requires the construction of new high-voltage transmission lines to
transport electricity to population centers. Because transmission lines can cross private,
public (state and federal), and tribal lands, the process of planning, permitting, and build-
ing new lines is highly visible and implicates many diverse interests—and it can be costly,
time consuming, and controversial.
Another major consideration for the installation of transmission lines from remote
locations (and any other location) is right of way (ROW). The right of way for a transmis-
sion corridor includes land set aside for the transmission line and associated facilities, land
needed to facilitate maintenance, and land needed to avoid risk of fires and other accidents.
It provides a safety margin between the high-voltage lines and surrounding structures and
vegetation (see Figure SB2.1.3). Some vegetation clearing may be needed for safety or
access reasons. A ROW generally consists of native vegetation or plants selected for favor-
able growth patterns (slow growth and low mature heights). However, in some cases, access
roads constitute a portion of the ROW and provide more convenient access for repair and
inspection vehicles. Vegetation clearing or recontouring of land may be required for access
road construction. The width of a ROW varies depending on the voltage rating on the line,
ranging from 50 feet to approximately 175 feet or more for 500-kV lines.
Before approval for new transmission is granted, the regulatory authority must deter-
mine that the project is necessary. Non-transmission alternatives must often be considered,
including energy conservation, energy efficiency, distributed generation, and fully utilizing
unused capacity on existing transmission lines. When new transmission lines are deemed
necessary, developers and utilities must find the best routes to the greatest concentrations of
renewable energy and build with the least possible impact on the environment. Transmission
lines from tall transmission towers carry high-voltage energy (115 to 500 kV) over long
distances to a substation. Both transmission and distribution lines (from substations) carry
enough energy to harm or kill both people and birds. Kill birds? Yes, actually, contrary to
popular belief, some birds are electrocuted by electrical power lines. Small birds do not usu-
ally get electrocuted because they fail to complete a circuit either by touching a grounded
