Addressing equity issue in multi-actor policymaking via a system-of-systems approach: Aviation emissions reduction case study

Finding equitable policy solutions is critical for developing sustainable energy use. This paper presents a system-of-systems (SoS) formalism for addressing the equity issue in multi-actor policymaking. In a SoS, the control of the overall system performance is shared among a network of actors. In contrast to a single optimal solution that aggregates objectives of actors, the solution concept of iso-performance is formulated and employed to illuminate multiple solutions and hence the 'space' for actors to compromise. By specifically accounting for the equity issue, the level of sacrifice each actor makes for each iso-performance solution is computed. To demonstrate the approach, a case study is presented about policymaking to reduce fuel life cycle aviation emissions in the United States based on the year 2020 reduction target, involving government, airlines, jet fuel refinery companies, and aircraft and engine manufacturers. A resource allocation mixed integer programming model is employed to calculate carbon emissions resulting from airlines' deployment of aircraft fleet to meet changing air transport demand. The paper discusses three iso-performance solutions; each of them requires a different level of sacrifice from each actor. Such an insight can inform policymaking in determining the magnitude of compensation required when a particular solution is pursued.