I understand that DC underground transmission is certainly used for long underwater interconnections. The ESB has informed me that the cost of putting transmission cables underground would be approximately 15 to 20 times more expensive than equivalent overhead lines. In addition, ESB's transmission network is based on AC current and the cost of conversion to DC would be extremely high. Therefore, for any application that the ESB may consider, the cost of underground DC transmission would be enormous and not economical.
Extensive research is being carried out worldwide in an attempt to establish if there is a link between adverse health effects on humans and the electromagnetic fields, EMF, emitted when electric current flows through objects such as power lines. Based on the research undertaken to date, there is not enough evidence to indicate that electromagnetic fields constitute a hazard to health.