Green Engineering and Sustainability: A Systems Analysis Perspective

This chapter presents a systems analysis perspective that extends the traditional plant design framework to green engineering, green energy and industrial ecology leading to sustainability. For green engineering this involves starting the design decisions as early as chemical and material selection stage on one end, and managing and planning decisions at the other end. However, uncertainties and multiple and conflicting objectives are inherent in such a design process. Green engineering principles are illustrated here using a green energy sector case study. Uncertainties increase further in industrial ecology. The concept of overall sustainability goes beyond industrial ecology and brings in time dependent nature of the ecosystem and multi-disciplinary decision making. Optimal control methods and theories from financial literature can be useful in handling the time dependent uncertainties in this problem. Decision making at various stages starting from green plant design, green energy, to industrial ecology, and sustainability is illustrated for the mercury cycling. Power plant sector is a major source of mercury pollution. In order to circumvent the persistent, bioaccumulative effect of mercury, one has to take decisions at various levels of the cycle starting with greener power systems, industrial symbiosis through trading, and controlling the toxic methyl mercury formation in water bodies and accumulation in aquatic biota.

Keywords: Green engineering principles, uncertainties, decision making, optimization, optimal control, stochastic optimization, multi-objective optimization, stochastic optimal control, mercury cycle, methyl mercury, pH control, nutrient control, trading, Savanna river water shed, fuel cell power plants time dependent uncertainty, Ito processes, financial engineering