Sustainable Systems: Measuring Carbon Emissions of Navy Ships

Many large and complex systems, which have service lives spanning decades, are not readily replaceable with new, environmentally sustainable designs despite the operating organization’s desire to mitigate carbon emissions. Hence, organizations must look toward how the extant system can become more sustainable through modification and/or operational changes. This paper investigates the potential for the US Navy to reduce emissions from its surface fleet of ships. The paper examines actions being taken by the commercial shipping industry, and then the paper adapts a measure of energy efficiency, the Energy Efficiency Existing Ship Index, to the context of combat ships. Measuring carbon emissions is important in order to identify how and where they can be reduced in the fleet. The paper describes the development of the measure and its application to existing ships. Navy ships currently perform worse in terms of emissions than comparable commercial ships, but this is largely due to redundancy in system design and operational characteristics such as speed. The results contribute to an enhanced understanding of the interplay between system design and system operation and how they affect the carbon emissions of the Navy’s surface fleet.