Due to a strong economic and demographic growth around the world, global energy needs are going to increase by about 35% from now until 2030 and energy must be saved. In addition to this, GHG emissions must be reduced in order to limit the consequences of global warming. In this context, TOTAL is working on minimizing flaring and on improving the energy efficiency of its existing and future facilities.

The in-house tool presented in this paper, EAT (Energy Architecture Tool), is primarily designed for future E&P facilities: it aids in the selection of an energy-efficient and low GHG-intensive architecture, during conceptual and pre-project studies. The tool allows doing the case-by-case approach instead of a "dogma" saying that a specific architecture is equally efficient in every case. It has been validated on four new projects.

Contrarily to studies based on design cases, i.e. extreme cases, this tool simulates the behavior of the energy generation unit (mostly gas turbines) and the energy users (compressors, pumps, furnaces), for the various flows, pressure and heat requirements over the field life. These requirements are less constraining than the design case, but they last much longer, and thus they are to be considered for the energy efficiency purpose.

EAT is a two-steps tool. The first step is to set a reference of energy consumption / GHG emissions. The reference is not a target but it is an ideally optimized case taking into account the process constraints (e.g. the amount of gas to be compressed, its molecular weight, the required suction/discharge pressures per year, site conditions…). The second step is the screening of several architectures to get as close as possible to this reference over the field life. The various alternatives simulated are: number of compression / pumping trains installed, load shedding strategy, use of constant or variable speed drive, all-electric configuration (turbogenerators and electrical drivers only) versus distributed power generation (e.g. turbocompressors), turbine model or other drives, electricity import or export etc.

Once the optimal architectures are identified, the Process, Operations, Technological and Architecture teams check the operability, availability, technical feasibility and economic profitability aspects.

The tool can also be used for existing fields, for building GHG mitigation plans, for setting challenging yet achievable objectives to Operations teams and for developing more accurate forecasts.

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