Low-environmental impact routeing of overhead power lines for the connection of renewable energy plants to the Italian HV grid

Routing of high voltage electric transmission lines for the connection of renewable energy distributed generation plants is a critical issue from an environmental point of view. A standard methodology that incorporates multiple weighted perspectives of influence is useful in the route approval by the governmental and regulating permitting entities and the support of the affected public. In this paper we investigate the suitability of the procedure employed by Terna, the leading electricity HV transmission grid operator, to identify the corridors with lower environmental impact where to route the new overhead transmission lines. The methodology is named ERPA and it is based on the subdivision of all the relevant constraints dictated by environmental issues and territory legislations in four classes: Exclusion, Rejection, Problem and Attraction. The case study that we take into account concerns the design and connection of a wind-farm placed near Collarmele, in the centre of Italy.