Dealing with uncertainties in long term transmission expansion planning problems

Transmission expansion planning corresponds to a very relevant issue that should not be forgotten in the scope of the implementation of market mechanisms in the electricity sector. This paper describes a multicriteria model to perform transmission expansion planning exercises that combines probabilistic models to represent the reliability of system components with fuzzy models to incorporate the uncertainty on load evolution along the planning horizon. This formulation also outputs long-term marginal prices that can be used to compute the Marginal Based Remuneration. The paper includes a case study based on the Portuguese 400/220/150 kV transmission network.