Techno-economic optimisation of large natural gas transmission systems

This article shares experience with the optimal design of large cross-country, onshore natural gas transmission systems. It is essential to find the techno-economic optimum depending on the different design criteria and to keep the balance between market flexibility and minimizing the capital expenditures as main target of the investors. Here the specific gas transportation costs serve as the main benchmark and allow proofing the economic viability of the project. The influence on the specific transportation cost is analysed based on different capacity utilization scenarios applied on a virtual large gas transmission system. For a pipeline system with line pipe diameter 56’’ and assumed optimal 30 bcm/a capacity the techno-economic optimisation results in specific transportation cost at approximately 3 €/1000 Nm³/100 km. Further it is illustrated how unused pipeline capacity leads to significant higher transportation cost. Due to commercial reasons it is therefore crucial to consider very short build-up phases until the full capacity of the pipeline system is reached. Further parameters with important influence on the specific transportation cost are the amount of capital expenditures, cost of capital and fuel gas cost.