Electric transmission lines transport or distribute electricity from region to region. Transmission lines are typically overhead wires at voltages of 110 to 765 kilovolts supported by towers. A transmission line is built within an area known as a right-of-way (ROW). The ROW is often 100 to 2,000 feet or more wide in order to accommodate maintenance of the lines. The Energy Policy Act of 2005 granted the Federal Energy Regulatory Commission the authority to approve and issue siting permits for new transmission lines in areas designated by the Department of Energy as National Interest Electric Transmission Corridors (NIETC).

Fish and Wildlife Considerations

There are more than 150,000 miles of high-voltage power lines across our nation, the equivalent of traveling around the earth's equator six times. With so many miles of transmission lines, there are many potential wildlife impacts that should be considered. Transmission lines and other linear developments like pipelines, roads and trails, can increase human access into natural areas, displace wildlife from their habitat, act as barriers to wildlife movement and affect migration routes. They have the potential to impact sensitive ecosystems such as wetlands, impact high quality fishery resources when waterways are crossed, and create pathways for the spread of invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

Learn more about invasive species .

Operation and maintenance of transmission line ROWs may also result in environmental impacts. ROW maintenance often involves the chemical or mechanical control of vegetation that can contribute to the loss of native plant species diversity. Cleared ROWs may be a continuous source of sedimentation into waterways. In addition to these potential impacts, transmission lines can pose collision and electrocution risks to migratory birds.

Learn about efforts to protect birds from power line electrocutions and collisions.