The shift from a fossil fuel system to a low carbon economy is changing the shape of power systems. This change is mainly driven by the deployment of large amounts of RES generation in the medium-term future, which will require a significant amount of transmission investments. However, the undertaking of these investments is at risk.

In order to address this problem, the European Commission has established a process to identify the projects that provide a high-value to the EU based on a CBA. But the process to determine the benefits and beneficiaries of projects is a controversial issue. This thesis aims to develop a comprehensive method able to assess the benefits and beneficiaries produced by expansion projects. This method uses cooperative game theory, in particular the Aumann-Shapley concept.