How well can one measure market power in restructured electricity systems?

The integration of national electricity systems into a single internal European electricity market is not progressing well with the result that the level of competition in the sector remains unsatisfactory. This had led to proposals to apply ex ante remedies that directly bear on the structure of national incumbents. These measures involve quantitative recommendations such as virtual auctioning of capacity or divestitures that increase the number of competing firms. The evaluation of these measures partly relies on computable oligopoly models of the restructured electricity sector. This paper analyses the recent literature of these models and concludes that they are not currently capable of providing the degree of legal and regulatory certainty that the importance of these ex ante remedies requires. The state of the art in these models is such that their results reflect more a set of non-testable assumptions than observed facts or unambiguous theory. More academic work is necessary before these models can be applied in a legal or regulatory context. The conclusion is that this work on the structure of national electricity market distracts from the fundamental objective to introduce competition in the power sector by integrating the national markets into a single electricity market