1 What Drives Efficiency on the Portuguese Gas Distribution?

The Portuguese natural gas sector is still growing, with a history of less than two decades. Consequently, the impact of regulatory reform is evidently recent. The aim of this paper is to assess the performance of the Portuguese gas distributors in order to define the efficiency targets for the regulatory period, 2010-2013. It also conducted further analysis in order to determine the best level of attainable operating costs by deriving the major costs driver of the Portuguese gas distributors. Therefore, the focus was on the deterministic frontier method, Data Envelopment Analysis (DEA) accounting for variable returns to scale (VRS). This technique allowed the computation of X-factors for each firm. The study suffered from data problems since the sector is very recent and the set of comparable companies is small. In order to avoid misspecifications or misinterpretations, firms were divided into three main groups with different scale factors and exogenous factors were also considered. The cross-section analysis was crossed with a dynamic one using panel data methodology