I. Introduction
One major goal of European energy policy is the establishment of a pan-European market. In regulation 1228/2003 of the European parliament and the council [1] it is stated that: “The creation of a real internal electricity market should be promoted through an intensification of trade in electricity, which is currently underdeveloped compared with other sectors of the economy.” Such a reinforcement of trade is not only an objective in the electricity sector. Similar reasoning exists for natural gas markets and related infrastructures. Hence, the priority projects for Trans-European Energy Networks (TEN-E) include both: recommendations in terms of investments in cross-border electricity and natural gas interconnections. Legislation regarding markets as well the stimulation of investment projects may be seen as two major measures to further intensify trade. However, the success of these strategies seems to be closely linked to the overall developments in terms of technological progress in energy generation and transmission, depletion of fossil resources and related price changes for primary energy carriers, national policies in terms of renewable integration, energy efficiency, etc.