5.4.2.2 Aircraft

QinetiQ (UK)^[38] analysed the fuel consumption and CO₂ trends for a simple global aviation growth scenario to provide an indicative view on the extent that technology and other developments might mitigate aviation emissions. The ICAO traffic forecast (ICAO/FESG, 2003) defined traffic growth to 2030 from which a future fleet composition was developed, using a range of current and future aircraft types where their introduction could be assumed, as well as representative aircraft types based on seat capacity. Fuel burn and emissions were calculated using known emissions performance and projections for future aircraft where necessary.

The analysis assumed a range of technology options as follows:

• Case 1 assumed no technology change from 2002 to 2030; using the extrapolated traffic forecast from ICAO FESG – this case shows only the effects of traffic growth on emissions.
• Case 2 – as Case 1, but assumes all new aircraft deliveries after 2005 would be ‘best available technology at a 2005 (BAT)’ performance standard, and with specific new aircraft (A380, A350, B787) delivered from 2008.
• Case 3 – as Case 1, but with assumed annual fleet fuel efficiency improvements as per ‘Greene’ and DTI (IPCC 1999, Chapter 9, Table 9.15). This assumes a fleet efficiency improvement trend of 1.3% per year to 2010, assumed then to decline to 1.0% per year to 2020 and 0.5% per year thereafter. This is the reference case.
• Case 4 – as Case 3, plus the assumption that a 50 US$/tCO₂ cost will produce a further 0.5% fuel efficiency improvement per annum from 2005, as suggested by the cost-potential estimates of Wit et al., (2002), that assume technologies such as winglets, fuselage skin treatments (riblets) and further weight reductions and engine developments will be introduced by airlines.
• Case 5 – as Case 3, plus the assumption of 100 US$/tCO₂ cost, producing a 1.0% fuel efficiency improvement per annum from 2005 (Wit et al., 2002), again influencing the introduction of additional technologies as above.

The results of this analysis are summarised in Table 5.13.

Table 5.13: Summaries of CO₂ mitigation potential analysis in aviation

Case 2 is a simple representation of planned industry developments and shows their effect to 2030, ignoring further technology developments. This is an artificial case, as on-going efficiency improvements would occur as a matter of course, but it shows that these planned fleet developments alone might save 14% of the CO₂ that the ‘no technology change’ of Case 1 would have produced. Case 3 should be regarded as the ‘base case’ from which benefits are measured, as this case reflects an agreed fuel efficiency trend assumed for some of the calculations produced in the IPCC Special Report (1999). This results in a further 11% reduction in CO₂ by 2030 compared with Case 2. Cases 4 and 5 assume that a carbon cost will drive additional technology developments from 2005 – no additional demand effect has been assumed. These show further CO₂ reduction of 11.8% and 22.2% compared with ‘base case’ 3 over the same period from technologies that are assumed to be more attractive than hitherto. However, even the most ambitious scenario suggests that CO₂ production will increase by almost 100% from the base year. The cost potentials for Cases 4 and 5 are based on one study and further studies may refine these results. There is limited literature in the public domain on costs of mitigation technologies. The effects of more advanced technology developments, such as the blended wing body, are not modelled here, as these developments are assumed to take place after 2030.

The analysis suggests that aviation emissions will continue to grow as a result of continued demand for civil aviation. Assuming the historical fuel efficiency trend produced by industry developments will continue (albeit at a declining level), carbon emissions will also grow, but at a lower rate than traffic. Carbon pricing could effect further emissions reductions if the aviation industry introduces further technology measures in response.