Daniel J. Garcia

Introducing Green GDP as an Objective to Account for Changes in Global Ecosystem Services Due to Biofuel Production

Abstract Accounting for ecosystem services is necessary for sustainable processes or systems. Biofuels production impacts land use change and, thus, ecosystem services. However, studies that minimise loss of ecosystem services from biofuels are rare. Ecosystem service values evaluate services – in monetary units – that ecosystems provide and could naturally be integrated into decision-making processes. The concept of Green GDP emerges when these values are considered with nominal GDP, providing an economic objective for large-scale biofuel value chains. We consider a biofuel value chain for the United States that considers process economics, supply chain economics, and the value of ecosystem services in a holistic, integrated model. First, we consider a case study where the objective is to maximise the US’s Green GDP before considering a case study where the objective is to minimise the overall annual cost. Loss of ecosystem services of the resulting value chain range from 4.7% to 6.8% of the overall cost of the value chain. Gains in green GDP compared to gains in nominal GDP are lower by 12.0% when optimising Green GDP and by 13.1% when optimising only for value chain cost.

Including Agricultural and Organic Waste in Food-Water-Energy-Waste Nexus Modelling and Decision-Making

Abstract The Food-Energy-Water-Waste Nexus (FEWWN) represents the interconnections between food, energy, water, and waste production systems and has become a key research area in recent years. Enormous quantities of agricultural and organic wastes are produced throughout the FEWWN, representing a hurdle to sustainability. Often, these wastes are not treated appropriately because their true costs are not only rarely quantified, but they are also usually externalised to the surrounding communities and environments. In this work, we address this shortcoming from a systems perspective fused with approaches from ecological economics and ecosystem service valuation. We construct a bioenergy production framework where the bioenergy may be produced from ethanol and/or agricultural and organic wastes. If waste is converted, we consider the regenerated ecosystem services as an economic benefit. We apply the framework to a multiobjective case study on the US state of Illinois where 160 PJ of bioenergy is to be produced considering objectives of net cost and Green GDP. Green GDP ranges from -

Multi-Stage Adaptive Robust Optimization over Bioconversion Product and Process Networks with Uncertain Feedstock Price and Biofuel Demand

125M/y to

Optimising the water-energy nexus over process and product networks

132M/y with corresponding net costs ranging from

Towards implementing a total capital cost budgeting constraint in MILP-based approximations to MIFP problems

107M/y to

Supply chain design and optimization: Challenges and opportunities

260M/y.

The water-energy-food nexus and process systems engineering: A new focus

Abstract Uncertainties abound in the biofuel industry and other product and process networks. Some key uncertainties include feedstock price uncertainty and product demand uncertainty. Product demand can guide strategic decisions such as sizing of capital equipment, and feedstock price can affect operational purchasing and processing decisions. We propose a multi-stage adaptive robust optimization approach to handle both of these different types of uncertainties in order to find the minimum total annualized cost of a bioconversion product and process network. Robustness of the solutions are controlled by budgets of the uncertainty, allowing for various solutions with varying levels of conservativeness. The minimum total annualized cost among the robust solutions ranges from

Multiobjective optimization of product and process networks: General modeling framework, efficient global optimization algorithm, and case studies on bioconversion

17.9M/y to

Unraveling Optimal Biomass Processing Routes from Bioconversion Product and Process Networks under Uncertainty: An Adaptive Robust Optimization Approach

22.5M/y. A solution with a good compromise between risk and cost was identified with a cost of

Network-Based Life Cycle Optimization of the Net Atmospheric CO2-eq Ratio (NACR) of Fuels and Chemicals Production from Biomass

21.9M/y.