The Northeast Blackout of 2003 cut power to approximately 55-million people in eight states and Canada. A tree coming into contact with a transmission line contributed to that massive outage.
After the blackout, new federal regulations with substantial penalties for noncompliance were created to ensure the reliability of the nation’s high-voltage electrical grid. These regulations mandate that minimum clearance distances between transmission lines and the nearest vegetation must be established. To comply with these regulations, NPPD has made it a policy to remove trees and other woody-stemmed vegetation within the transmission line right-of-way as well as tall-growing trees located outside the right-of-way that could interfere with the continuous safe operation of the transmission system. In many cases, this means removing trees in areas where they may have been only been trimmed in the past.