Who should be responsible for generation capacity addition?

There is an ongoing discussion of who should be responsible for adding new capacity to the power system in the deregulated environment. One first step in this discussion is who should be responsible for that there must be enough reserve capacity available in the system. In Sweden, this responsibility is rather unclear in the legislation, where it is stated that the system responsible is responsible for the "short term" balance in the system. This implies of course primary control, but where is the time limit? If "short term" includes the next day, then the consequence is that the system responsible also will be responsible for capacity expansion! In this paper, three different suggestions of how to solve the problem of reserve capacity are discussed. Finally a newly introduced system is presented as well as the coupling to the question of who should be responsible for generation capacity addition.