Incorporating environmental impacts in strategic redesign of an engineered system

Large engineered systems do not often live out their life cycles as originally planned. Traditional methods do not address redesign issues that arise during long term operation of these systems. The problem of how to consider the environmental impacts of stranded assets is especially problematic, particularly during system operational changes. This paper presents a method for analysis of a dynamically changing system that includes consideration of both economic and environmental impacts. A case study of an electrical power system illustrates the approach. Using a 100 yr time period and using several decision rules (e.g., keep all plants operating until planned retirement age or retire all plants 10% early), the aggregated results were derived. The best sequence of decision or decision rule can now be determined by the highest multiattribute utility score. The best decision sequence is one that immediately retires and decommissions all fossil fueled electrical power plants, although early retirement without immediate decommissioning produces inferior utility values. There is little gained in utility when extending operational life of the plants, and as the 100 yr period moves forward, all solutions collapse on the final system configuration. The results provide several insights that were gained through the ability to forecast the environmental impact caused by changes within the life cycle phases of a system, such as early retirement or operational life extension of facilities.