As long as there will be a cost price difference for energy in the various countries there will be a demand for interconnection capacity for import as well as for export capacities. The capacity for interconnections is limited due to the fact that there is no copper plate principle but a system with limitations concerning safety and capacities. Eventually the cross border capacity available to the market is determined by the physical capacity of the tie-lines itself but also of generation and consumption in the transmission grid. Congestion is caused by the thread of acceding the limits of to the market safely available transmission capacity by expected or realized transmission flows. Congestion management method With congestion management is meant the method applied, not taking into consideration expansions of the transmission grid or interconnections itself, which will manage the for the market maximum available transmission capacity, taking into account the limitations of the electricity supply system within the boundaries of the security of supply. In the following document TenneT explains the congestion management method applied on its interconnections: PDF document