Life cycle assessment of underground cables

The increasing use of underground cables instead of overhead lines for electricity transmission for acceptability reason or landscaping integration raises the question of its environmental impacts. To reduce the impact of underground cables, it can be necessary to carry out eco-design studies which will help identify the most efficient areas for improvement. In order to be as relevant as possible, such an approach implies to take into account every phase of the life cycle of the underground cable: manufacture of the cable, operation phase and end of life. To that end, Life Cycle Assessment (LCA) methodology turns out to be a precious tool. Defined by the ISO standard 14040, this method takes into account every phase of the life cycle related to studied good or service, from the extraction of raw materials to the disposal of wastes which are produced, in order to carry out a multicriteria evaluation of the potential impacts of the studied system on the environment. The implementation of this method requires the achievement of a balance sheet for the consumptions of energy, natural resources, and for the emissions of polluting substances. These material and energy flows are then incorporated into models which will bring quantified information on the environmental impacts with the help of specific indicators. LCA method applied to underground cable can be used to: - improve one given technology by identifying phases of the life cycle responsible for the most important share of the environmental impact, and acting on it; - compare different solutions or system having the same function (for instance underground cable