11. Systems Modeling and Technology Sensitivity Analysis

This chapter takes a functional view of how technologies can and should be evaluated in a systems context. The main point is that technologies don’t have value on their own. Only in the context of a “host” system or product can technologies be properly evaluated. The simplest way to do this is to generate a two-level decomposition with the product or system at level 1 and the constituent technologies at level 2.

Once this decomposition is done, we perform system modeling to quantitatively relate the technological variables and figures of merit (FOMs) at level 2 to product-level FOMs at level 1. This then enables a sensitivity analysis to see how much a unit improvement in a specific technology will improve a product or system at the level above. When constrained system optimization is performed, we obtain the Lagrange multipliers (also known as shadow prices) for the active constraints in the system. This is a powerful way to quantify how technological progress can move or eliminate active constraints in the system, which leads to further improvement in the FOMs at the product or system level. Said differently, it may not help to improve a technology at the lower level, if it is not somehow associated with an active constraint at the system or product level. Understanding this in a quantitative way is a crucial – and often overlooked – element of technology roadmapping. Examples in this chapter include aircraft, diesel exhaust aftertreatment systems, as well as local resource production on the Moon (This is also known as in situ resource utilization (ISRU). Examples of ISRU include drilling for water ice on the Moon or on our neighboring planet Mars. The recent MOXIE experiment on the Mars 2020 Perseverance Rover has demonstrated oxygen production from the CO₂-rich Martian atmosphere using a technology called solid oxide electrolysis (SOE)).