A systematic and structured approach is presented to identify a complete set of transmission stress tests in an entry-exit system. The tests can be used to determine the size and capacity of the system. The method is based on the transport load for balanced entry-exit combinations, without having to rely on detailed properties of the network, nor on an extensive evaluation of all possible combinations.

For long distance transport, the stress tests result from maximization of the product of throughput and mean transport distance in all relevant directions through the system. Local transport stress tests can be generated in a similar way, by focusing on the appropriate part of the network and applying the procedure locally. Multi-route systems require additional treatment to ensure that all relevant paths are addressed.

The method can be extended to transmission systems in which, apart from transport phenomena, blending of different gas qualities plays a role. This may require the use of additional load parameters to the transport load.

Our approach finds its application in capacity planning issues for gas transmission networks and can be of particular interest for natural gas TSOs using decoupled entry-exit systems - as in many European countries. The procedure can be straightforwardly implemented as a pre-processing algorithm in pipeline simulation programs.

Decoupled Entry-Exit

Transmission system operators (TSOs) in the European Union are required to supply entry and exit capacity to the market in a decoupled way [1]. This implies there are no point-to-point contracts; instead, shippers contract entry and exit capacity independently and may use this capacity without having to maintain entry-exit balance at all times individually (of course, the transmission system as a whole must be in balance).

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