Emissions Mitigation Strategies

**145**

in emissions.

**Chapter 8**

Strategy

**Abstract**

*Oluwaferanmi Oguntona*

emission mitigation, aircraft retirement

**1. Introduction**

Increasing the Emission

an Economically Optimised

Transport Aircraft Retirement

Mitigation Potential by Employing

This study investigates the emission mitigation potential of retiring passenger aircraft economically at the global fleet level. In an integrated model of the air transport system, fleet turnover aspects of the global passenger aircraft fleet are defined using aircraft lifetime direct operating costs. Two fleet renewal strategies are compared in the study. The growth strategy (the baseline scenario) prioritises aircraft allocation for serving demand growth and replacing aircraft retired at the end of their design lives, before replacing those that are retired because of their operating cost disadvantage. Conversely, the replacement strategy allocates global aircraft production capacity first for replacing aircraft that are retired based on their operating cost disadvantage and those retired on reaching their design life limit, before serving growth in air travel demand. Results show that in year 2024, emission savings of three percent were achieved at the global fleet level using the Replacement Strategy, when compared to the baseline. Afterwards, due to the unavailability of newer efficient aircraft, emission savings diminish to two percent (around 40 million tonnes of CO2). This research is useful to aviation stakeholders in having an

overview of expected emission savings of the proposed strategic measure.

**Keywords:** fleet renewal strategies, aircraft direct operating cost, aviation emissions,

There were around 28,000 commercial aircraft as of 2017, and out of these, 22,337 passenger jet aircraft have operations that yielded around 859 million tonnes of CO2 [1–3]. Based on forecast of growth in air traffic, aviation emissions are also expected to grow in the long term. For example, Japan Aircraft Development Corporation [3] claimed that approximately 33,500 aircraft would be added to the global fleet over the next 20 years. The International Civil Aviation Organization [4] also claimed that a five percent growth in air traffic, compared to the projected one to two percent annual increase in aircraft fuel efficiency, would lead to the growth
