(381f) Sustainable Design of Energy Supply Chains From P-Graphs: Cost, Ecological Footprint, and Emergy

A collaboration consisting of the Office of Research and Development (ORD) of the U.S. EPA and the research group led by the founders of the P-graph framework at the University of Pannoniahas developed a methodology for designing sustainable supply chains based on an optimization using the p-graph framework constrained by integrated sustainability indicators and engineering costs.  The result was a powerful methodology for designing cost-effective and environmentally sustainable supply chains.  We illustrated the methodology with a prototype supply chain designed to produce heat and electricity for a generic district in Hungary.  Possible sources of heat and electricity included electricity from the Hungarian grid, and heat and electricity generated from natural gas, corn, corn silage, grass silage, or wood or some combination of these sources.  Twenty-one different supply chains, each capable of producing 18 TJ per year of heat and 7.2 TJ per year of electricity were found.  Each supply chain was ranked according to cost, and assessed environmental impacts using the ecological footprint (representing land use burden), and emergy (representing energy resource burden).  Decisively feasible supply chains were found with cost variations of +2% to -17% compared to “business as usual” scenarios i.e. using only natural gas and electricity from the Hungarian grid.  For these supply chains, the sustainability profile as represented by the ecological footprint varied from +8% to -78%, and the emergy results ranged from -54% to -93%.  Both comparisons were done in contrast to the conventional natural gas/electricity from the Hungarian grid. Most importantly, it appeared feasibly possible to  design supply chains for heat and electricity generation which were both cheaper and more sustainable than the supply chain currently in use.