(773b) Incorporating Water Resources, Electricity Supply, and Allocation of Sequestered CO2 in the Nationwide Hybrid Energy Supply Chain

Previously developed frameworks on the nationwide energy supply chain analysis for transportation fuels based on hybrid coal, biomass, and natural gas to liquids (CBGTL) processes are expanded to incorporate water supply chain, electricity resources, and feasible allocation of sequestered CO₂ [1-9]. The CBGTL plants are optimized using from an expanded superstructure that includes syngas conversion to liquid fuel products via both Fischer-Tropsch reactions and methanol intermediate [6-8]. The fuels can be upgraded in a standard upgrading section similar to the operation of petroleum refineries, or over zeolite catalysts. Multiple carbon conversion levels (i.e., 40%, 50%, and 60%) are imposed to represent varying degrees of feedstock utilization and electricity production for the single plant, giving a total of 162 distinct configurations of CBGTL facilities that may exist in the supply chain. Each of the topology is optimized with simultaneous heat, power, and water integration approaches.

Water, electricity, and CO₂ sequestration considerations are incorporated both on the single plant level and on the supply chain level. On the individual plant, freshwater consumption and wastewater discharge are minimized via the water integration approaches. On the supply chain level, United States data on water availabilities are incorporated in the model constraints and the transportation cost to deliver water to the CBGTL plants is included in the objective function. The three carbon conversion levels give rise to plant topologies that are net producers (lower conversion levels) and net consumers of electricity (higher conversion levels). In the supply chain analysis, combinations of these plants are used to achieve a target of total electricity consumption in the United States such that the grid electricity expansion does not exceed 10% of the current capacity (i.e., 102.5 GW). Finally, in a single CBGTL plant, CO₂ is either vented, recycled, or captured for sequestration to fulfill a minimum of 50% emissions reduction from petroleum-based processes. The pipeline investment, transportation and injection costs of the captured CO₂ are incorporated in the supply chain analysis.

Case studies are presented to illustrate the performance of the optimal supply chain network for multiple levels of petroleum fuel replacement (i.e., 50%, 75%, and 100%) for the United States. A case study using the locations of current energy infrastructure (i.e., coal mines and oil refineries) is also included to examine the trade offs between facility location selections and the overall cost of fuel production.

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