It is a recognized fact that the lack of public and political Support is one of the main sources of delay in building new transmission lines. In an energy era where there is an increasing lag between transmission grid development and the rapid generation growth, it is essential to streamline the related transmission line approval procedures. There is a strong relationship between stakeholder engagement on one side, and acceptance and support on the other side. The aim of the paper is to investigate ways of fostering acceptance of transmission lines through participation by analyzing in detail the case of a disputed France-Spain interconnection project. We argue that participatory processes should embrace not only an instrumental rationale, but also normative and substantive rationales. Based on literature and the case study, we analyze this important condition for effective participation in transmission planning procedures. (C) 2013 Elsevier Ltd. All rights reserved.