How do underground lines compare to overhead lines with respect to operating costs, line loss, capital cost, EMF, other health and safety concerns, and environmental impact?
Construction & Operating Costs The capital cost to install high-voltage transmission lines underground can range from four to twenty times the cost of overhead lines. Additional expense depends on the length of the line and the geotechnical, physical, and environmental conditions of the area. We are currently reviewing the technical feasibility and costs for underground construction for this project. Operation and maintenance costs are not a significant component of overall expense and have generally not influenced a choice of between underground and overhead lines in the past. Line Losses Line losses are considered in the size of the overhead wires or underground cable. EMF The electric fields from underground cables are shielded by the wire’s insulation and the earth, but the magnetic fields are not. Typically, the magnetic field could be higher immediately on top of a buried transmission line than below an overhead line, depending on the design. However, the magnetic field from an u
