Free riding effect in multi-national transmission expansion planning

The transmission system in EU is run by different TSOs with different nationalities, ownerships, and internal policies. This makes the transmission planning for the European Integrated Electricity Market difficult. In fact, each TSO tries to act strategically in order to maximise his social welfare and they are reluctant to act in a cooperative solution. In the context of multiple inter-connected transmission systems, it's very important to incentives TSOs to act in a cooperative solution. However, free riders are always waiting for other TSOs to push on transmission expansion and they make benefit out of it without contributing to the expansion. In this paper, we model the free riding effect and analyse its economic consequences in an inter-connected network by comparing two cases: considering congestion revenue just for cross-border lines and considering congestion revenue not only for cross-border lines but also for intra-area lines. Each transmission planner is modelled as a social-welfare maximising firm using a mixed-integer linear programming problem. This study is carried out on a Nine-bus network consisting of three TSOs.