We install overhead electric transmission lines for three primary reasons: 1) cost, 2) installation disruption and 3) outage restoration. Cost: Undergrounding an electric transmission line is approximately quadruple (3 to 5 times) the cost of an overhead equivalent; a cost that would be borne by all Colorado Springs Utilities’ ratepayers.
Disruption: Although it is often assumed that undergrounding a large transmission line is less disruptive to surrounding property owners and vegetation, it is actually more disruptive to both. During initial installation, and in cases of service restoration efforts, considerable digging and vegetation clearing is required. Use of space under an overhead line can be maximized, but usable space over a buried electrical system is limited. For example, trees can grow under the transmission line and be limited to a certain height, but they cannot grow or have a root ball over underground cable.
Service restoration: If an electric outage is traced to an underground transmission line, the process of finding the exact cause of the failure is much more involved. It is sometimes necessary to make several digs to find the source. This translates into much longer outages and more disruption to roadways, easements and surrounding vegetation.