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
