This paper discusses the optimization of linepack usage in gas networks to meet the demand for flexibility in consumptions. The rapid development of flexible gas plants known as CCGTs (Combined Cycle Gas Turbines) and the recent evolutions of the energy markets makes it a key issue in computing capacities for TSOs. This paper describes the operating principles of tools designed by CRIGEN to address this subject, highlighting the respective roles of steady-state- and transient-modeling in that task.
GRTgaz owns, develops, maintains and operates the main part of the French gas transmission system (a highly meshed network composed of over 20 000 miles of pipes, 25 compression stations, over 4500 delivery points, that transmitted 640 TWh of gas in 2011). In the last few years, GRTgaz, has experienced challenging evolutions in energy regulation and in its relation to energy markets. One of them, maybe the most remarkable, is the development of many CCGTs. The capacities of those consumers are expected to double between 2010 to 2020, to account for a quarter of the transmitted flows in 2020. This paper presents how CRIGEN combined its existing tools and its expertise in the fields of complex networks, steady-state and transient modeling to help GRTgaz compute and optimize the available linepack for a given set of transmission capacities. Since the notion of available linepack is relative to different factors, rather than focusing only on the computation of a simple number, the paper also discusses the different impacts of the most remarkable factors we studied. We will then discuss the use of linepack in operations, and how the dynamic of utilization of linepack affects the value of the available linepack : depending on how linepack is used, there can be different amounts of available linepack.
