Air Travel – Greener by Design Mitigating the environmental impact of aviation: Opportunities and priorities

Abstract

The Technology Sub-Group of Air Travel – Greener by Design was instituted at the first full meeting of the GBD community in March 2000. Its first period of intense activity was from the summer of 2000 to the spring of 2001, culminating in the publication of its report The Technology Challenge in July 2001 at the first Air Travel – Greener by Design Conference at the Royal Aeronautical Society. In the period that followed, the contents of the report were further disseminated by presentations at conferences and publication of the report in The Aeronautical Journal but there was no substantial activity by the Sub-Group as such. In July 2003, a workshop on ‘The Effect of Aviation on the Atmosphere’, was held at St Catherine’s College, Cambridge. This was planned jointly by members of the Sub-Group and of the Centre for Atmospheric Science in the Department of Chemistry at Cambridge and was jointly funded by GBD and the EC project SCENIC. The organisation of events on the day and the collating and editing of the workshop report was done by Dr Helen Rogers of the Centre for Atmospheric Science. The workshop was attended by a broad cross section from the manufacturing and operating industries, government and academia and its report is a valuable summary of current understanding in 2003.

Airplane Design Optimization for Minimal Global Warming Impact

“…I, the engine design can have a strong effect on the emitted species. Although high pressure ratios and temperatures typically lead to reduced fuel consumption, and thus low(er) CO 2 emissions, they also increase the production of thermal NO x [16]. The production of NO x is also influenced by the detailed combustor design, which is not captured by the current design vector and is out of scope for the current study.…”

“…Although it was shown that such engine cycle modifications can yield a significant reduction in fuel burn (33 to 45% for a large single-aisle aircraft), they may have an adverse effect on non-CO 2 climate effects. Raising the OPR and TET, for example, increases the formation of thermal NO x [16], although the emission index of NO x in LTO and cruise can be further reduced through future combustor technologies [17]. Additionally, increasing the bypass ratio of turbofan engines increases the probability of contrail formation [18].…”

Airplane Design Optimization for Minimal Global Warming Impact

“…As briefly introduced in Section I, the engine design can have a strong effect on the emitted species. While high pressure ratios and temperatures typically lead to reduced fuel consumption and thus low(er) CO 2 emissions, they also increase the production of thermal NO x [14]. The production of NO x is also influenced by the detailed combustor design, which is not captured by the current design vector and is out of scope for the current study.…”

“…Although in recent years the bypass ratio (BPR), OPR and TET have been increased to decrease the specific fuel consumption, this may have an adverse effect on climate impact. Raising the OPR and TET, for example, increases the formation of thermal NO x [14], while increasing the bypass ratio of turbofan engines increases the probability of contrail formation [15]. This demonstrates that optimizing for minimum fuel burn, again, does not necessarily align with the objective of minimizing global-warming impact.…”

Integrated design and allocation of optimal aircraft departure routes

“…From a practical implementation point of view, it can be observed that the variation of aircraft/airport operational procedures emerges as a suitable option that can result in short term improvements and could be less costly in comparison with the other options. For this approach, the optimal design of routes for departures and arrivals, and the allocation of aircraft to these routes are considered as the most promising options (Green, 2005).…”