Sustainable Aviation. CO 2 Road-Map.

Transcription

1 Sustainable Aviation CO 2 Road-Map

2 SUSTAINABLE AVIATION CO 2 ROAD-MAP 2012 Sustainable Aviation is a unique alliance of the UK s airlines, airports, aerospace manufacturers and air navigation service providers. Together, we drive a long term strategy to deliver cleaner, quieter, smarter flying. SA is the first alliance of its type in the world, and reports regularly on progress in reducing aviation s environmental impact. Executive Summary This document sets out Sustainable Aviation s projection of future CO 2 emissions from UK aviation. Our projection is based on recently published UK-Government forecasts of aviation demand-growth, together with our own assumptions concerning the deployment of technology, sustainable fuels, operational measures and carbon trading. We conclude that UK aviation is able to accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. Projection of CO 2 Emissions from UK Aviation UK aviation can accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. Government will play a key role in supporting research and development in aerospace technology, encouraging the introduction of sustainable biofuels, delivering on infrastructure projects such as the Single European Sky initiative, and working with other countries to establish a global sectoral approach for regulating international aviation emissions based on carbon trading. We do not support unilateral UK targets and measures as they would be unnecessary and counter productive. Such measures would deliver no overall environmental benefit, but would result in carbon leakage, market distortion, and the loss of economic benefits to our international competitors. Recent and future developments in aircraft and engine technology will play a major role in reducing UK aviation s carbon intensity. We anticipate absolute CO 2 emissions will continue to fall post-2050 due to the ongoing penetration into the fleet of new wide-body aircraft types entering service from around 2035 onwards. The same technologies will also be deployed on a worldwide basis, with a correspondingly greater CO 2 mitigation impact. Page 1 of 58

3 The potential for sustainable biofuels to reduce CO 2 emissions from UK aviation has increased dramatically over the past three years. During this period, two classes of sustainable fuel have been certified for commercial use, and there has been considerable diversification in the range of potential feedstocks and processing routes being developed. This area continues to develop rapidly. Improvements in air traffic management and operational procedures will also play a material role in reducing the carbon intensity of aviation in the coming decades. Although UK aviation currently accounts for some 5-6% of global aviation s CO 2 emissions, this proportion is likely to fall significantly over the next few decades due to rapid growth in large developing aviation markets such as China, India, and Latin America. Looking forwards therefore, significant UK influence over CO 2 emissions from aviation will be achieved not through restricting the scale of UK aviation activity, but rather through internationally focussed efforts. Government should therefore: support the development of more efficient aircraft and engine technologies which will be deployed on a worldwide basis; support the development and large-scale deployment of sustainable aviation fuels offering very significant life-cycle CO 2 savings relative to conventional fossil-based fuels; work with international partners to enable more efficient air traffic management on nondomestic routes, within the context of increased capacity requirements; press for agreement on and support implementation of a global carbon-trading solution encompassing all of aviation and ensuring a level playing field for all participants. Key areas in which this (2012) CO 2 Road-Map differs from our previously published (2008) CO 2 Road- Map are as follows: The demand-growth trajectory upon which our Road-Map is based now takes account not only of growth in passenger numbers but also of changes in the average distance travelled by passengers, and of growth in cargo flights. Our view of the extent to which more efficient engines and aircraft will impact fleet fuel efficiency now benefits from greater clarity concerning the capabilities of aircraft types due to enter service during the current decade. Our assessment of the likely impact of sustainable fuels upon UK aviation s CO 2 emissions takes account of the significant progress made in this field over the past three years. Our assessment of the likely mitigation impact of improved air traffic management is now based on a bottom up analysis which includes the impact - on flights which depart from UK airports - of the fuel-burn reduction target adopted by the UK s air navigation service provider. The global aviation emissions objective to reduce net CO 2 emissions to 50% of 2005 levels by 2050 using carbon trading is presented. Aviation is a globally interconnected industry and needs a global solution to address its emissions in a cost effective manner without introducing competitive distortions. Any unilateral targets and measures that attempt to limit UK aviation s emissions through capacity constraints or price-related demand reduction will lead to carbon leakage, market distortion and the loss of economic benefit to our international competitors. We do not support the inclusion of international aviation emissions in UK carbon budgets. Our Road-Map shows that such unilateral policy measures are not necessary and that UK aviation can accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of aviation s net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. Page 2 of 58

4 Contents 1 Introduction Sustainable Aviation UK Aviation s Economic Value Aviation and the Environment UK Aviation in the International Context The First SA Road-Map a Retrospective View Motivation for an Updated Road-Map Methodology Scope of the SA CO 2 Road-Map The Role of Government Document Structure Hypothetical No-Improvements Scenario Introduction Demand Growth Projections The Hypothetical No-Improvements Scenario Overview of Mitigation Opportunities Introduction Industry Motivation and Commitment Potential Mitigation Approaches Improvements in Air Traffic Management and Operations Introduction Air Traffic Management (ATM) APU Substitution Aircraft Operations Assessment of Potential Mitigation Impact Improvements in Aircraft and Engine Efficiency Introduction Aircraft Technology Overview of Options Engine Technology Overview of Options Fuel Efficiency Improvements the Evidence Base Aircraft Fuel Efficiency Assumptions Impact on Fleet-Average Fuel Efficiency Sustainable Fuels Introduction UK Initiatives Sustainability Overview of Sustainable Fuel Categories Economics of Biojet Scale-Up and Deployment European Advanced Biofuels Flightpath Assessment of Potential Mitigation Impact Carbon Trading Introduction The Need for a Global Approach Assessment of Potential Mitigation Impact Summary of Assumptions Demand Growth Mitigation Assumptions The Sustainable Aviation CO 2 Road-Map Page 3 of 58

5 9.1 The Road-Map Discussion Average Rates of Improvement Comparison of SA s Projection with DfT s CO 2 Forecasts Comparison of SA s and CCC s Mitigation Assumptions Conclusions References APPENDIX A Fleet Turnover Assumptions APPENDIX B Distribution of Fuel-Burn APPENDIX C Less Likely Mitigation Options APPENDIX D Comparing the 2008 and 2012 Road-Maps APPENDIX E Impact of Fuel Efficiency on Mission Fuel-Burn APPENDIX F ATM efficiency improvements in NATS airspace Page 4 of 58

6 1 Introduction 1.1 Sustainable Aviation Sustainable Aviation (SA) is a unique alliance of the UK s airlines, airports, aerospace manufacturers and air navigation service providers. Together, we drive a long term strategy to deliver cleaner, quieter, smarter flying. SA is the first alliance of its type in the world, and reports regularly on progress in reducing aviation s environmental impact. Over the past 50 years, the aviation industry has delivered dramatic improvements in emissions. SA is now looking at how the industry can deliver even more advances over the next 40 years. We are undertaking work to reduce emissions from aircraft whilst on the ground, reviewing our CO 2 Road-Map and contributing to the roll out of the Departures Code of Practice. SA supports a global agreement on aviation emissions with the goal of securing a 50% reduction in global aviation s net CO 2 emissions by 2050 relative to 2005, as agreed by the International Air Transport Association (IATA), Airports Council International (ACI), International Coordinating Council of Aerospace Industries Associations (ICCAIA) and the Civil Air Navigation Services Organisation (CANSO). 1.2 UK Aviation s Economic Value Aviation brings economic benefits to society as a whole and to the UK in particular, supporting trade, investment and employment. In 2009, the combined activities of airlines, airports, ground services and aerospace directly contributed 24.0 billion to UK GDP, whilst directly supporting 352,000 jobs in the UK. The aviation sector s supply chain contributed a further 16.6 billion to UK GDP in the same year [OE, 2011]. The UK s aerospace manufacturing sector is the world s second largest, directly employing 105,000 people and directly generating 10.3 billion of UK GDP in 2009, with a further 7.6 billion of UK GDP being generated by the aerospace sector s supply chain [OE, 2011]. The sector brings further economic benefits through the generation of intellectual property which frequently has spin-off benefits in other sectors. 1.3 Aviation and the Environment The aviation industry takes extremely seriously its responsibility to reduce its environmental impact, as its track record illustrates. Over the last half-century, fuel-burn per passenger-kilometre has been reduced by some 70 percent against a backdrop of progressively tightening noise and NO x regulations. The industry remains resolute in its drive to reduce emissions even further, as demonstrated not only by the commitments of aircraft operators to refreshing their fleets with newer, more efficient aircraft, but also by significant investment in ongoing research and development [SA, 2011], [SA, 2009] to ensure that future generations of aircraft are even more efficient. Recently the European Commission s High Level Group on Aviation Research has published a vision for aviation in 2050 entitled Flightpath 2050 [HLG, 2011], calling for a reduction in CO 2 emissions per passenger kilometre of 75%, a 90% reduction in NO x emissions and a 65% reduction in perceived noise emissions from flying aircraft. This vision is benchmarked against the capabilities of a typical new aircraft in However, aviation s social and economic contribution to society is such that underlying demand for air travel continues to rise, placing upward pressure on emissions. This Road-Map brings together Page 5 of 58

7 analysis from the various sectors of the UK industry, together with demand-growth projections from the UK s Department for Transport [DfT, 2011], to provide a balanced view of the likely trajectory of CO 2 emissions from UK aviation over the period to UK Aviation in the International Context CO 2 emissions from UK aviation 1 currently correspond to around 5-6% of CO 2 emissions from aviation worldwide. Whilst UK aviation s growth rates 2 to 2050 will average around 2% per annum [DfT, 2011], global growth rates are expected to be considerably higher due to the rapid development of emerging markets in Asia and elsewhere. As a result, the proportion of global aviation s emissions attributable to the UK is likely to diminish over time. The most compelling opportunity for the UK to exert an influence over CO 2 emissions from aviation is therefore not by constraining demand for UK aviation, but rather through investment in advanced technologies 3 which can be deployed globally, earning export revenues for the UK while contributing to a more environmentally efficient industry world-wide. To illustrate the comparative scale of the global mitigation opportunity, analysis by IATA [IATA, 2010] has shown that global commercial airline fuel efficiency has improved by over 30% in the past two decades, saving over 400 million tonnes of CO 2 per annum at current activity levels, relative to the fleet efficiency in In contrast, total annual emissions of CO 2 attributable to UK aviation correspond to less than one tenth of this figure. Since CO 2 is a well-mixed greenhouse gas, the geographical or sectoral distribution of CO 2 emissions does not influence the climate system s response to those emissions. Accordingly, the pursuit of the most cost-effective mitigation opportunities, irrespective of sector or geography, should be incentivised. Aviation should be therefore be regulated at the global level, avoiding a patchwork of competing and conflicting national and regional emissions regulation which would lead to carbon leakage and market distortions. We strongly oppose including international aviation in the UK carbon budget or introducing national targets or measures aimed at reducing international aviation emissions. If international aviation were included in the UK budget, this would lead to perverse policy decisions that would not reduce global emissions, but would only give the illusion of a reduction in UK emissions. For this reason we support the drive for a global sectoral agreement to regulate CO 2 emissions from international aviation. 1.5 The First SA Road-Map a Retrospective View With the first version of the SA Road-Map [SA, 2008a], issued in December 2008, the UK aviation industry presented for the first time a consensus view of its likely CO 2 emissions trajectory to The analysis therein was informed by input from all four sectors of the industry - manufacturers, airlines, airports and the UK s air navigation service provider. Based on clearly laid out assumptions and calculations, the first SA Road-Map set out our view that CO 2 emissions from UK aviation would not - as some had suggested - occupy 50% or even 100% of the UK s carbon budget by 2050, but rather would return to below 2005 levels by At the time of the first Road-Map s publication, audited figures for actual CO 2 emissions from UK aviation were available up to and including Since that time figures for have become available [NAEI, 2011]. Figure 1 illustrates the level of agreement between actual CO 2 emissions and corresponding figures derived from the first Road-Map so as to take account of actual passenger numbers. 1 Our interpretation of this phrase is set out in section In terms of passenger numbers 3 This would include not only engine and aircraft technologies, but also bio-fuel technologies and ATM-related technologies. Page 6 of 58

8 Figure 1 Comparison of actual CO 2 vs. the first SA CO 2 Roadmap (adjusted for actual passenger numbers). Data sources: [CAA, 2010], [NAEI, 2011], [SA, 2008a]. 1.6 Motivation for an Updated Road-Map Since our first CO 2 Road-Map was conceived and developed, there have been a number of developments which have a bearing on the likely future trajectory of UK aviation s CO 2 emissions. We have taken the opportunity to revise our Road-Map, taking account of the latest evidence available to us. Developments since late 2008 include the following: The impact of the global economic downturn upon future levels of demand for UK aviation was assessed by the UK s Department for Transport in their growth forecast released in the summer of 2011 [DfT, 2011]. The benefits of a more efficient single-aisle airliner will be seen earlier than previously anticipated, due to the two largest manufacturers both offering a re-engined aircraft type in this category, with entry into service expected around the middle of this decade. The level of ambition of European aerospace research, and the timescale over which that ambition extends, has benefitted from renewed focus. The European Commission s High Level Group on Aviation Research published in 2011 a vision for aviation in 2050 entitled Flightpath 2050 [HLG, 2011]. Certification for commercial aviation of two main classes of biofuel blends has been achieved. In summer 2011, a small number of scheduled airline services commenced operations using fuel partly derived from biomass. This area continues to develop rapidly. The aviation industry now has visibility of the implementation of aviation s incorporation in the EU Emissions Trading Scheme. At the global level, ACI, CANSO, IATA and ICCAIA collectively announced in 2009 a commitment for the international aviation industry to pursue a 1.5% per annum improvement in fuel efficiency up to 2020, to achieve carbon neutral growth from 2020, and to reduce net carbon emissions (relative to 2005 levels) by 50% by 2050 [ACI, 2009]. Also at the global level, the UN s aviation body, ICAO, declared in 2009 a requirement to pursue improvements in fuel efficiency (defined as volume of fuel used per RTK 4 performed) of 2% per annum up to 2020, and an aspiration to pursue the same rate of improvement up to 2050 [ICAO, 2009]. 4 RTK = revenue tonne kilometre Page 7 of 58

9 Further, in 2010, ICAO resolution A37-19 set out an aspirational goal of keeping the global net carbon emissions from international aviation from 2020 at the same level, together with an intention to work with member states to develop a framework for market-based measures (MBMs) in international aviation [ICAO, 2010]. 1.7 Methodology The approach taken in this issue of our Road-Map is as follows: We first consider the likely growth in demand for UK aviation, using it to derive a hypothetical no-improvements emissions scenario, corresponding to a constant level of technology, operational practices and biofuel adoption. We then consider in turn the potential for mitigation from the adoption of improvements in airtraffic management and operational practices, more efficient engines and aircraft, and the use of sustainable biofuels. Having established the potential mitigation opportunity, we then set out our assumptions concerning the extent to which that potential will be realised. We also present the potential contribution of aviation s participation in carbon trading, which can deliver the most cost effective carbon reductions across the economy as a whole, and will allow aviation to purchase carbon reductions from sectors where they may be achieved more economically. 1.8 Scope of the SA CO 2 Road-Map In this document we interpret UK aviation to mean flights which depart from UK airports. This is consistent with the accounting convention used by the UK to assess emissions from UK aviation. Our use of this interpretation is motivated by the need for consistency with published figures and does not imply support for or agreement with the corresponding accounting practice. Besides carbon dioxide, emissions from aviation also include oxides of nitrogen (NO x ), water vapour, particulates, carbon monoxide, unburned hydrocarbons, soot and oxides of sulphur (SO x ). The climate impact of many of these is discussed in a separate paper [SA, 2008b]. This Road-Map focuses purely on CO The Role of Government Bringing to fruition the projection set out in our Road-Map will not only require the continued commitment and focus of the aviation industry itself, but will also rely on engagement from Government, which should: support the development of more efficient aircraft and engine technologies which will be deployed on a worldwide basis; support the development and large-scale deployment of sustainable aviation fuels offering very significant life-cycle CO 2 savings relative to conventional fossil-based fuels; work with international partners to enable more efficient air traffic management on nondomestic routes, within the context of increased capacity requirements; press for agreement on and support the implementation of a global carbon-trading solution encompassing all of aviation and ensuring a level playing field for all participants. In reaching our view of the extent to which mitigation options identified in this document will reduce CO 2 emissions from UK aviation, we have assumed that suitable levels of Government engagement will be achieved with respect to each of the above areas. Page 8 of 58

10 1.10 Document Structure The remainder of this document is structured as follows: In section 2 we establish a hypothetical no-improvements scenario detailing the notional growth in CO 2 emissions from UK aviation that would take place assuming no improvements in fleet fuel efficiency, no improvements in operational practices, and no adoption of sustainable fuels. In sections 3 to 6 we set out our assumptions and analysis concerning the potential for aviation to improve its carbon intensity through a variety of measures. Section 7 sets out the need for a global approach using carbon trading to reduce aviation s net emissions, and allowing aviation to fund mitigation actions in other sectors in those cases where they can be achieved more cost effectively than within the industry itself. Section 8 brings together the assumptions employed in our Road-Map. Finally, section 9 presents the Road-Map itself along with a discussion of its key messages. Comparisons with the results of other recent publications in this area are also presented. Page 9 of 58

11 2 Hypothetical No-Improvements Scenario SUMMARY in the absence of any improvements in fleet fuel efficiency or in operational practices, and assuming no use of biofuels, CO 2 emissions from UK aviation would rise 150% between 2010 and 2050, implying an average annual growth rate of 2.32%. 2.1 Introduction In this section we identify the hypothetical trajectory that UK aviation s emissions could be expected to follow in the absence of any action to improve the industry s carbon intensity. This no-improvements trajectory then serves as a reference against which the potential impact of our anticipated improvement activities can be assessed. Our hypothetical no-improvements scenario assumes a constant level of technology, operational procedures, and biofuel penetration, in which more aviation activity is delivered at the same load factors using an increasing number of the same types of aircraft without changing over time the manner in which they are operated, or the type of fuel used. It is worth pointing out that this scenario does not correspond to a business as usual scenario, since business as usual involves the rigorous pursuit of cost-reduction opportunities of which improving fuel efficiency - and hence carbon intensity - is a major part. 2.2 Demand Growth Projections In the previous SA Road-Map [SA, 2008a] we used forecasts of growth in passenger 5 numbers published by the UK s Department for Transport (DfT) as the basis for our estimate of growth in delivered aviation activity. Whilst this was an adequate proxy for our purposes, we were nonetheless aware that a better proxy would have been a forecast of delivered revenue passenger kilometres (RPKs) 6, on the basis that RPK growth also captures changes in the average distance flown by passengers. Although a long-term forecast of RPK growth was not available to us at the time of the previous SA Road-Map, the DfT s most recent forecast document [DfT, 2011] tabulates RPK growth for each of DfT s three scenarios. Figure 2 comparison of DfT s Central growth forecasts for passenger numbers (pax) and revenue passenger kilometres (RPKs). Source: SA analysis based on data from [DfT, 2011] 5 Passengers - often abbreviated to pax 6 RPKs for a single flight, this term is the product of the number of passengers carried and the distance travelled Page 10 of 58

12 Figure 2 compares DfT s Central forecasts for growth in passenger numbers to the corresponding forecast for growth in RPKs 7. The chart illustrates that the difference, whilst material, is not large, since over the 40 year period RPKs are forecast to grow by a factor of 2.3, whilst passenger numbers are forecast to grow by a factor of 2.2. Nonetheless, with respect to the growth in CO 2 emissions that would take place in the reference scenario, we believe that RPKs are more representative than passenger numbers. For this reason we employ DfT s Central RPK growth forecast in our reference scenario. However, our usage of DfT s growth forecasts does not imply our support for the policy assumptions upon which those forecasts are based. Whilst the above discussion refers to passenger flights, emissions from freight-only flights must also be assessed for their significance. In addition to forecasts of RPKs, [DfT, 2011] also presents forecasts of freight tonnes carried on freight-only flights, together with an estimate of the average distance travelled by such flights. The following procedure establishes a common framework in which growth forecasts of passenger activity and freight-only flights are combined in our hypothetical noimprovements scenario: Freight-only flights accounted for 3.2% of UK aviation s 33.4 MtCO 2 emissions in 2010, with the remainder being attributable to passenger-flights 8. Using these values we establish separate baseline figures for CO 2 emissions in 2010 from 1) passenger-flights and 2) freight only flights. Using DfT s forecasts of freight tonnes carried on freight only flights, coupled with DfT s forecast of the average distance of freight only flights 9, we estimate the growth over time of FTKs 10 carried by freight-only flights. The 2010 baseline emissions figures for each of the two flight categories is then scaled up - according to the growth in delivered RPKs or FTKs relative to to yield a trajectory for each category. These can then be added to yield the total, as shown in section The Hypothetical No-Improvements Scenario The hypothetical no-improvements scenario employed in the 2012 SA CO2 Road-Map directly tracks the sum of the following two terms which are summarised in Table 1: CO 2 emissions arising from the growth in FTKs on freight only flights, derived from data presented in Table G.12 of [DfT, 2011], and assuming that in 2010, freight only flights accounted for 3.2% of UK aviation s total 33.4 MtCO 2 emissions (as set out in Table H.6 of [DfT, 2011]. CO 2 emissions arising from the growth in passenger RPKs set out in Table G.11 of [DfT, 2011], assuming that in 2010 passenger RPKs accounted for the remaining 96.8% of UK aviation s 33.4MtCO 2. In our hypothetical no-improvements scenario, illustrated in Figure 3, CO 2 emissions from UK aviation rise by 150% during the period from 2010 to 2050, implying an average annual growth rate of 2.32%. In subsequent sections of this document we examine opportunities for mitigating this growthdriven upward pressure on CO 2 emissions from UK aviation. 7 DfT s growth forecasts take into account the impact on demand of factors such as carbon pricing 8 Table H.6 of [DfT, 2011] 9 Table G.12 of [DfT, 2011] 10 FTKs = freight tonne kilometres Page 11 of 58

13 Year RPKs (Billion) MtCO 2 Pax Flights FTKs (Billion) MtCO 2 Freighters MtCO 2 Total CO 2 Growth Factor Table 1 Key figures relating to the hypothetical no-improvements emissions trajectory used in this CO 2 Road-Map. Source: SA analysis based on Central demand forecast from [DfT, 2011]. Use of DfT s growth forecasts does not imply SA support for the policy assumptions underpinning those forecasts. CO 2 % Growth Figure 3 UK aviation CO 2 emissions in a hypothetical no-improvements scenario in which technology levels, operational practices, and biofuel penetration levels remain unchanged from Scope: flights which depart from UK airports, including passenger flights and freight-only flights. Source: SA analysis based on Central demand forecast from [DfT, 2011]. Use of DfT s growth forecasts does not imply SA support for the policy assumptions underpinning those forecasts. Page 12 of 58

14 3 Overview of Mitigation Opportunities 3.1 Introduction Although the aviation industry has made significant progress over the past few decades in reducing its carbon intensity, principally through improvements in fuel efficiency, many opportunities for further improvement remain. This section gives a brief overview of the wide variety of carbon mitigation opportunities that may be envisaged. In subsequent sections we explore these opportunities in more detail and set out our view of the extent to which some of them will contribute to reductions in UK aviation s carbon intensity. 3.2 Industry Motivation and Commitment The increase in oil prices witnessed over the past decade or so has meant that fuel-related costs now constitute a significantly greater percentage of airline operating costs than in the past. Figure 4 illustrates that since 2006 the global airline industry s annual jet fuel bill has greatly exceeded $100 billion. IATA 11 estimates that in 2011, fuel will account for 30% of global airline operating costs. Charges associated with participation in carbon-trading schemes present additional fuel related costs to aircraft operators. We believe that the significance of fuel-burn within the balance of drivers influencing aircraft and engine design, fleet renewal and operating practices is likely to increase still further in the future. Figure 4 Global airline industry spend on jet fuel. Data source: IATA 11 The resulting incentive for improved fuel efficiency is clear. Aviation has made significant progress over the past few decades in terms of reductions in fuel-burn per passenger kilometre. The significant rises in fuel price observed over the past decade only strengthen the drivers for continued progress. 3.3 Potential Mitigation Approaches In broad terms, the carbon footprint of a flight (per revenue tonne-kilometre) can theoretically be reduced by a combination of the following: Increasing the energy-per-unit-mass and/or energy-per-unit-volume of the fuel used. Increasing the efficiency with which fuel energy is converted into thrust by the engine(s). Increasing the aircraft s aerodynamic efficiency (lift to drag ratio). Reducing the structural weight of the aircraft for a given payload-range requirement. Reducing engine weight. Reducing the weight of aircraft systems and cabin infrastructure viewed 04 Oct Page 13 of 58

15 Cruising at reduced speed. Adapting aircraft design to maximise the advantages of reduced cruise speed. Using an aircraft whose range capability does not greatly exceed the mission s requirement. Making full use of the aircraft s mass-carrying capability at the desired range. Optimising stage-length. Adopting the most fuel-efficient route, taking weather and prevailing winds into account. Avoiding queuing or holding, whether on the ground or in the air. Replacing ground-based APU usage with lower-carbon power from airport infrastructure. Taxiing using fewer engines, or by towing the aircraft. Ensuring the aircraft and all its systems are operating at their most efficient state of maintenance. Using a lower carbon intensity sustainable fuel derived from biomass or waste. Capturing carbon-dioxide from the air and using it to artificially manufacture aviation fuel. Capturing carbon dioxide from the air and sequestering it. Reducing net emissions through funding more cost-effective emissions reduction in other economic sectors. Each of these options is subject to the commercial realities of a highly-competitive industry, in which fuel costs and carbon costs, while significant, are not the only drivers. Some of these options therefore will not in our view contribute materially to reducing aviation s carbon intensity before 2050, as we discuss further in Appendix C. Nonetheless, the remaining opportunities collectively present considerable scope for reducing the carbon intensity of air travel. Subsequent sections of this document present our view of the extent to which they will be pursued. Page 14 of 58

16 4 Improvements in Air Traffic Management and Operations SUMMARY Improvements in air traffic management and operational practices have the potential to improve the fuel efficiency of UK aviation by around 13.5% by 2050 relative to For the purposes of our Road-Map, we assume a 9% improvement. 4.1 Introduction In this section we examine the potential for improvements in aviation s carbon intensity arising from the more efficient operation and management of aircraft. We consider the following broad categories of opportunity: Air Traffic Management (ATM) - covering such aspects as optimised routing and altitude profiles, and the reduction of queuing or holding. This category also includes the management of aircraft flows on the ground. APU substitution - consisting of the use of electrical power and conditioned air provided more efficiently from airport infrastructure rather than from the aircraft s own auxiliary power unit (APU) when the aircraft is on the airport stand. Aircraft operations covering operationally-related sources of improvement such as higher load-factors and the optimisation of fuel-loads. 4.2 Air Traffic Management (ATM) Introduction Allowing aircraft to follow fuel-optimal routings and altitude profiles offers potential for significant reductions in CO 2 emissions. Minimisation of queuing and holding offers some further scope for CO 2 reduction. [CANSO, 2008] assessed the efficiency of global ATM provision and concluded that there exists an opportunity to improve global ATM efficiency by an average of 3 to 4 percentage points. However, the same report also makes clear that current ATM efficiencies in Europe are a few percentage points lower than the global average. This leads to a greater than average opportunity for ATM-related improvement in Europe. Figure 5 Distinction between typical stepped altitude profile and the optimal altitude profile which reduces fuel-burn. Source: [SA, 2011] Page 15 of 58

17 Opportunities for improvements in ATM and operational practices can be grouped broadly into groundbased opportunities and airborne opportunities. Examples of improvements currently being delivered include: ground-based: reducing taxi times, and improved taxiing techniques; airborne: better climb profiles avoiding inefficient level segments, more direct routes, improved access to fuel-efficient flight levels, achieving economic speeds, reducing reliance on airborne holding and working towards better descent profiles (see Figure 5). Several initiatives are underway to demonstrate and realise the potential savings that can be achieved through more effective routing and management of aircraft. [SA, 2011] describes the Perfect Flight 12 live trial which took place in July 2010 and demonstrated a reduction in CO 2 emissions of some 11% on a flight from Heathrow to Edinburgh, through the use of an optimal flight profile (see Figure 5) and the minimisation of delay at all stages of the flight. The ASPIRE initiative has demonstrated optimal flights on longer-haul routes across the Pacific, and assesses the average fuel-burn reduction opportunity on routes between the US and Australia/New Zealand to be in the region of 4% 13. The European SESAR project 14 aims to facilitate the defragmentation of European airspace to enable significant ATM-related efficiency improvements within this busy region. The Atlantic Interoperability Initiative to Reduce Emissions (AIRE) is working to demonstrate and validate solutions for gate-to-gate improvements in emissions from flights in the Atlantic region. NATS (the UK s air navigation service provider) has set a target to achieve a reduction of ATM CO 2 by an average of 10% per flight by , and has an active programme in place to deliver this Assessment of Mitigation Opportunity for UK Aviation Before assessing below the opportunities for reducing UK aviation s CO 2 emissions through advances in ATM efficiencies, we first set out the overlap and distinction between 1) CO 2 emissions from flights which depart from UK airports, 2) CO 2 emissions from flights whilst under NATS control, and 3) CO 2 emissions from flights whilst under the control of other ANSPs 16. Each flight within NATS control can be regarded as falling into one of four categories: overflights, domestic flights, inbound international, and outbound international. Notwithstanding the above categorisation, each flight can be regarded as consisting of a number of distinct phases: ground operations, climb, en-route, and descent. Not every phase of each UK-departing flight will take place under NATS control (e.g. the descent phase of an outbound international flight occurs elsewhere). Furthermore, not every flight under NATS control falls within the scope of our Road-Map. Over-flights and inbound international flights, for example, do not originate from a UK airport and thus lie outside our scope. NATS estimates that in 2006, CO 2 emissions in NATS controlled airspace from flights which departed from UK airports 17 amounted to 12.3Mt. We now consider the potential ATM-related CO 2 reduction in each of three categories: 12 Video containing more detail available at 13 Source: ANSPs = air navigation service providers 17 Only flights which depart from UK airports are within scope of our UK CO 2 Road-Map Page 16 of 58

18 Improvements implemented within NATS airspace by 2020: Appendix F details the relationship between the CO 2 reduction target adopted by NATS and the corresponding impact on CO 2 emissions from flights which depart from UK airports. In summary, we estimate that total savings achievable on flights which depart from UK airports, as a result of successful delivery of the NATS 10% target, amount to 3.9% of UK aviation s CO 2 emissions. Although in the analysis presented in Appendix F this saving is expressed relative to the stated 2006 baseline, the phasing of delivery is such that the vast majority will be achieved post We therefore take this 3.9% as being the available saving relative to the SA Road-Map s 2010 baseline. To take account of possible uncertainties, in our Road-Map we conservatively assume a contribution of 3.0% from this source. Improvements implemented outside NATS airspace by 2020: We anticipate that other ANSPs will also deliver improvements in ATM efficiency within the next decade, and that these will yield CO 2 reductions during the en-route and arrival phases of outbound international flights once they leave NATS airspace. We conservatively estimate that the benefit to these flights corresponds to two tenths of the 10% efficiency improvement targeted by projects such as [SESAR]. In 2006, CO 2 emissions outside NATS airspace attributable to flights which departed from UK airports amounted to 25.7Mt 18. Saving 2% of these emissions would yield a reduction of 0.51 MtCO 2 relative to 2006 emissions, corresponding to 1.3% of total UK aviation CO 2 emissions in Again, due to the anticipated phasing of delivery of these savings, we take this 1.3% as being relative to the Road-Map s 2010 baseline. To take account of possible uncertainties, in our Road-Map we take 1.0% as the likely contribution from this source. Other ATM-related improvements implemented : While many major airspace improvements will have been delivered by 2020, there will remain further scope for improvement in airspace structures as well as in technology to manage traffic flows and improve separation minima so that aircraft can achieve more optimum flight profiles. New navigation technologies, restructuring of airspace boundaries and traffic management techniques offer potential for reductions in fuel-burn in excess of 5%, over and above savings delivered prior to However, to allow for uncertainties concerning the level to which this potential might be realised, we conservatively assume a further saving of some 2.5% of all CO 2 emissions from all UK originating flights which will become effective gradually between 2020 and The above discussion is summarised in Table 2. ANSP Timescale Phase of Flight Saving (% of UK aviation CO 2 ) Assumed Potential NATS Pre 2020 All Other Pre 2020 En-Route, Descent NATS & Other Post 2020 All TOTAL Table 2 potential reductions in CO 2 emissions from flights which depart from UK airports, arising from anticipated improvements in ATM efficiency 18 38MtCO 2 total [NAEI, 2011], minus the 12.3MtCO 2 taking place in NATS airspace, leaves 25.7Mt outside NATS airspace. 19 Values rounded to the nearest 0.5% Page 17 of 58

19 4.3 APU Substitution Opportunities to reduce CO 2 emissions from aircraft on the airport stand through the provision of lower-carbon electrical power and/or conditioned air from airport infrastructure rather than from the aircraft s own APU 20 were discussed in [SA, 2010a], [SA, 2011]. This approach also offers potential for reducing noise and NO x emissions. The Aircraft on the Ground CO 2 Reduction (AGR) Programme [SA, 2010a], [SA, 2011] was developed following two years of collaborative work involving Sustainable Aviation led by Heathrow Airport and with the input of the Clinton Climate Initiative. The programme has a simple and pragmatic objective to develop practical guidelines for airports working with partners to cut aircraft ground movement CO 2 emissions and also improve local air quality. Heathrow was used as a case study, where it was shown that ground emissions are approximately 30% of the airport's total footprint (excluding the en route phase) and are therefore significant (see Figure 6). Figure 6 Carbon footprint of London Heathrow Airport, 2008, excluding emissions from the en-route phase of flight. Source [SA, 2010a]. The programme captures best practices across the industry today with potential for even greater efficiency improvements in the future. Practical action steps for airports, airlines, air navigation service providers and ground handling companies to reduce emissions are clearly set out in the innovative programme. In addition to exploring reductions in APU usage, the programme also examined the CO 2 savings achievable through using a reduced number of engines when taxiing aircraft. It is estimated that these two practices at Heathrow are already saving 100,000 tonnes of CO 2 per year against a do-nothing scenario, even after accounting for increased airport electricity consumption in place of APU usage. The Airport Operators Association (AOA) is leading on extending the programme across other UK airports and has already secured support from 23 airports across the country. Recognising that there remain some uncertainties surrounding the potential impact on taxiway capacity arising from significant deployment of reduced engine taxiing, for the purposes of our Road- Map we take account only of the benefits of APU substitution. Based on data presented in [SA, 2010a] the potential future savings from APU substitution represent at least 50% of current CO 2 emissions from APUs. If this reduction is applied on a national basis to the level of APU emissions stated in DfT s 2010 baseline 21 it would represent a reduction of 0.2Mt in CO 2 emissions from APUs, equivalent to a 0.6% reduction in UK aviation s overall CO 2 emissions. This assumes that the combined potential for savings achievable at airports beyond Heathrow is of a similar magnitude to the remaining opportunity at Heathrow itself. 20 APU = auxiliary power unit 21 Table H.6 of [DfT, 2011] CO 2 emissions from APUs at UK airports amounted to 0.4MtCO 2 Page 18 of 58

20 The potential for APU substitution to deliver savings in CO 2 emissions from UK aviation relative to a 2010 baseline is therefore estimated at around 0.6%. This compares well with separate studies carried out by Zurich Airport and IATA, which have estimated potential of circa 0.6% fuel savings globally from APU substitution. To account for uncertainties we take as input to our Road-Map an assumed 0.3% saving from this source. 4.4 Aircraft Operations We estimate the potential for reductions in UK aviation s fuel-burn through improvements in aircraft operational practices to be in the region of 2.9%. For the purposes of our Road-Map, we assume improvements of 2.1% will be delivered by 2050, as set out below Passenger Load-Factor An aircraft is at its most fuel-efficient when its load-carrying capacity is fully utilised. Aircraft operators have achieved considerable success over the past decade with respect to increasing passenger load factors 22 through the use of increasingly sophisticated revenue management systems. Despite the improvements already made, it is believed that there remains a small but material opportunity to obtain further increases in passenger load factor, corresponding to an improvement in fuel-use per passenger kilometre of some 2%, of which we conservatively take 1.5% as input into our Road-Map Optimised Fuel-Loads It is recognised that on occasions the amount of fuel loaded into an aircraft s fuel-tanks prior to flight is in excess of that which is actually required to complete the mission 23. A common reason for this is over-estimation of payload [ICAO, 2003]. We estimate that the potential for fuel-burn reduction, without compromising safety, arising from more accurate fuel-loading is in the region of 0.5%. For the purposes of our Road-Map, we assume 0.3% improvement from this source. This phenomenon is distinct from fuel tankering, the latter being the intentional carriage of potentially large volumes of fuel between airports for commercial reasons. Motivations for tankering are discussed in [ICAO, 2003] and may include significant variations between airports of fuel price, quality or availability, or may reflect a need to minimise turnaround times at busy airports. We do not takeaccount of any reductions in tankering activity within this Road-Map Other Operational Opportunities Further opportunities for reducing aircraft fuel-burn through operational measures are available. These include regular engine and airframe cleaning, the checking of door-seals for drag-inducing defects, and the removal of dents from the aircraft s external surfaces. These are discussed in [ICAO, 2003]. Small additional savings may be realisable through weight-reduction measures applied to cabin interiors 24, and through the carriage of reduced amounts of potable water. We estimate the potential for fuel-burn reduction arising from a combination of these measures to be in the region of 0.4%. For the purposes of our Road-Map, we assume 0.3% improvement from these measures. 4.5 Assessment of Potential Mitigation Impact Based on the discussion above, we conclude that the combined potential for improvements in ATM and operational practices to reduce CO 2 emissions from UK aviation is in excess of 13%. However, taking account of uncertainties concerning the extent to which that potential will be realised in practice, 22 Corresponding to the proportion of installed seats actually occupied by passengers 23 After allowing for fuel-reserves required for safety purposes 24 As distinct from the improvements in cabin infrastructure discussed in section Page 19 of 58

21 in our Road-Map we assume a 9% reduction in CO 2 from UK aviation arising from improvements in ATM and operations. Table 3 summarises the key figures presented in this chapter. Category % CO 2 Saving Deployment Assumed Potential Timescale ATM To 2050 APU substitution To 2030 Aircraft Operations To 2050 TOTAL To 2050 Table 3 potential reductions in CO 2 emissions from UK aviation, due to anticipated improvements in ATM efficiency and operational practices 25 Values rounded to the nearest 0.5% Page 20 of 58

22 5 Improvements in Aircraft and Engine Efficiency SUMMARY 1) We calculate that introduction of the imminent generation of aircraft types will improve the fleet-average fuel efficiency of UK aviation by some 17% by 2050, with the bulk of this improvement delivered by ) We take the view that introduction of the subsequent generation of aircraft types from 2025 onwards has the potential to improve fleet average fuel efficiency within UK aviation by a further 26% by 2050, taking account of likely fleet penetration by that date. 3) This yields a combined potential improvement in fleet-average fuel efficiency of some 39% 26 arising from the introduction of more fuel-efficient engines and aircraft between 2010 and ) Post 2050, improvements in fleet-average fuel efficiency will continue due to the ongoing penetration into the fleet of aircraft types first entering service from the mid 2030s onwards. However, those improvements lie beyond the time-horizon of our Road-Map and therefore do not feature in our analysis. 5) Still further improvements in fleet-average fuel efficiency will be possible post 2050 due to the entry into service of a further generation of new aircraft types towards 2050 (not considered in our Road-Map). 5.1 Introduction This section sets out our view of the potential for improvements in aircraft and engine fuel efficiency to reduce UK aviation s carbon intensity by We detail in turn: technology options for improving aircraft and engine efficiency (sections 5.2 and 5.3); the evidence base concerning past, imminent and potential future improvements (section 5.4); our assumptions concerning the fuel efficiency of imminent and future aircraft, relative to their respective predecessors (section 5.5); our assumptions concerning the rate at which new aircraft enter into the fleet, and the resulting impact upon fleet-average fuel efficiency (section 5.6). 5.2 Aircraft Technology Overview of Options Increasing Structural Efficiency Reducing the structural weight of an aircraft can yield significant benefits for reduced fuel consumption. Successive generations of aircraft have demonstrated impressive reductions in weight through such measures as the use of advanced alloys and composite materials, manufacturing processes, and lighter systems such as fly-by-wire 27. For example, aircraft designed in the 1990 s were based on metallic structures, having up to 12% of composite or advanced materials. In comparison, the A380, which has been flying since 2005, incorporates some 25% of advanced lightweight composite materials generating an 8% weight saving (representing a 17% improvement from imminent generation aircraft types) multiplied by 0.74 (representing a further 26% improvement from next generation aircraft types) yields 0.61 i.e. a combined improvement of 39%. 27 The reduction of engine weight (discussed in section 5.3) also contributes to a reduction in total aircraft empty weight. Page 21 of 58

23 relative to similar metallic equipment. The A350 XWB will feature as much as 50% composite material, including composite wings and parts of the fuselage, increasing the weight savings to as much as 15%. Looking to the future, extensive usage of nano-materials could bring further weight savings. Examples may include: conductive nano-filler which increases the electrical conductivity of composite materials, reducing the need for additional electrical grounding such as metallic grids or ground wirings; inter-laminar reinforcements leading to a stronger vertical interconnection between composite layers, requiring less material for a given stress; Image: Airbus intra-laminar reinforcement that grows carbon nanotubes directly on fibres. This would lead to a stronger interconnection between carbon fibres and therefore would require less material for a given stress capability. Image: Airbus Additive layer manufacturing (ALM) manufacturing is often referred to as 3D printing, as the technique builds a solid object from a series of layers - each one printed directly on top of the previous one. The raw material for ALM is a powder, which can be a thermopolymer or a metal; aluminium, stainless steel and titanium 6-4 are common. Research on brackets has shown that ALM is a promising technology that provides 40% weight saving Increasing Aerodynamic Efficiency Reducing aerodynamic drag has a direct impact on fuel-burn. As Figure 7 illustrates, friction drag and lift-dependent drag are the largest contributors to aerodynamic drag. Friction drag represents about 50% of aircraft overall drag, and is dominated by contributions from the fuselage and wings. Page 22 of 58

24 Figure 7 Aerodynamic drag elements of a modern aircraft. Source: Airbus. Advances in materials, structures and aerodynamics currently enable significant lift dependent drag reduction by maximising effective wing span extension. Wing-tip devices can provide an increase in the effective aerodynamic span of wings, particularly where wing lengths are constrained by airport (and/or hangar) gate sizes. Friction drag is the area which currently promises to be one of the largest areas of potential improvement in aircraft aerodynamic efficiency over the next 10 to 20 years. Possible approaches to reducing friction drag include the reduction of local skin friction through encouraging laminar flow, either through passive or active means. The BLADE project will conduct large-scale flight test demonstration of laminar wings on a flying test bed, commencing in Image: Airbus New aircraft architectures could provide further significant improvements. The Very Efficient Large Aircraft (VELA) project has already researched blended wing concepts which would deliver per-seat fuel consumption improvements of up to 32% over current aircraft designs Aircraft Systems There are a number of options for fuel-burn reduction through improved aircraft systems exhibiting lower weight and/or lower power requirements. For example: The replacement of hydraulic systems with electrical systems on aircraft such as the A380 and A350 brings weight benefits as well as simplicity and enhanced maintenance. Looking forwards, further improvements are envisaged that move towards a 100% electrical system, but continued research is necessary to achieve high power levels with reliability and certification, together with the necessary cooling requirements. The use of fuel cells for powering aircraft systems on board an A320 was demonstrated in Hydrogen-powered fuel-cells offer the potential for emissions-free electricity generation, and could lead to significant weight savings through the replacement of several other systems such as the auxiliary power unit (APU), ram air turbine, and batteries. However, offset against those weight savings would be the weight of the hydrogen storage itself. A wireless cabin could reduce the cabling weight associated with in-flight entertainment systems etc. Page 23 of 58

25 The use of electric motors, installed in aircraft landing gear and powered by the aircraft s APU, present possible opportunities for reducing fuel-burn during taxiing. The concept has already been demonstrated in trials. However, offset against the reduction in fuel-burn during the taxi phase would be the weight of the motors themselves. The net benefit will therefore depend on factors such as the ratio of taxi-distance to flight-distance Cabin Infrastructure Improvements Total payload mass load factor is influenced not only by the proportion of installed seats that are occupied, but also by the number of seats installed. The reduction of space occupied by cabin infrastructure can have a significant impact on fuel-burn per passenger kilometre, by allowing the installation of additional seats and hence the carriage of additional passengers without necessarily reducing the living space available to each passenger. If the weight of the additional passengers including their luggage and seats is offset by weight reductions in the redesigned cabin infrastructure, then the reductions in CO 2 per passenger kilometre can be substantial: The SPICE galley concept by Airbus [SA, 2011] can save kg of weight and enough space to gain 2-3 economy seats, on a typical widebody aircraft seating passengers 28. The addition of 2-3 extra seats on such an aircraft can reduce fuel-burn per passenger-kilometre by at least 1%, since the galley design s reduced weight more than offsets the weight of the additional passengers, their luggage and their seats. New lighter and thinner seat designs offer potential for installing additional seats with little or no weight penalty. An additional row of seating can offer improvements in fuel-burn per passenger kilometre of 2% or more, when coupled with the installation of lighter-weight seats across the entire aircraft Aircraft Design Choices Although technology, materials and manufacturing technologies will continue to play a significant role in supporting improved aircraft fuel efficiency, other potential improvements arising from alternative aircraft design choices have also been documented: [Poll, 2009] states that designing the aircraft for a cruise Mach number of around reduces by about 10% the energy required to deliver a unit of revenue work 30, relative to that at a design cruise Mach number of [ICAO, 2011] suggests that modest changes in design Mach number, design range and wingspan can lead to fuel efficiency savings of the order of several percent. Aircraft cruising speeds are determined by a range of customer-driven requirements which include the balance between fuel-related costs and time-related costs associated with owning and operating aircraft. The expectation of significantly higher fuel and carbon prices over the in-service lifetime of an aircraft could, in principle, change this balance to the extent that designing the aircraft for a slower cruise speed (particularly for shorter flights where the time-penalty is likely to be small) may prove economically attractive Example: Assume 35 rows replaced with 36 rows due to thinner seat design enabling reduced seat-pitch with no loss of legroom. Assume seat weight reduction of 25% versus initial seat weight of 15kg. Assume weight of 1 passenger (including luggage) is 100kg. Total weight after replacement (seats plus passengers plus luggage) is no greater than total weight before replacement. Fuel-burn and hence CO 2 per passenger-kilometre is therefore reduced by around 2.8%. 30 Related to the number of tonne-kilometres performed Page 24 of 58

26 5.3 Engine Technology Overview of Options Introduction The specific fuel-consumption (sfc) 31 of a jet engine is characterised by two key aspects. Firstly, thermal efficiency describes the effectiveness with which the fuel s chemical energy is turned into kinetic energy. Secondly, the propulsive efficiency indicates how well the kinetic energy is turned into thrust. Thermal efficiency is influenced by the temperatures and pressures reached in the engine s core. Cooling technologies and/or high-temperature materials therefore play a key role. Thermal efficiency is also influenced by the component efficiencies of the compressor and turbine, which can be improved through advanced design methods. Propulsive efficiency is improved by increasing the engine s bypass ratio a measure of how much air travels around the core compared with that which travels through the core. The bypass ratio of jet engines has increased steadily over the past few decades, and is set to increase further with the adoption of ultra-high bypass ratio architectures such as open-rotor solutions. Although both of these efficiency factors are subject to theoretical limits, significant reductions in specific fuel consumption beyond that of today s engine types are nonetheless possible. Open rotor engines, for example, are envisaged which could offer a 30% reduction in mission fuel-burn relative to today s technology turbofans 32. However, the engine s influence on mission fuel-burn is not restricted to the specific fuel consumption of the engine itself. A typical large jet engine can weigh several tonnes and weight minimisation is therefore a key engine design driver. Weight reduction has the added advantage of reducing the thrust requirement and can therefore have a positive benefit for emissions and noise as well as for fuel-burn Advances in Design Methods, Modelling and Analysis The ongoing development of computational tools which enable high-fidelity physics-based modelling coupled with the optimisation of design parameters continues to yield benefits for engine performance and weight minimisation. The availability of high-performance computing facilities allows the exploration of greater numbers of potential designs, in greater detail. For example, modern computational fluid dynamics (CFD) analysis tools enable the design of high-lift low-pressure turbine airfoils which can enable the same work to be achieved with a significantly reduced blade count, leading to reduced weight 33. Integration of different types of tools increasingly supports multi-disciplinary analysis connecting materials modelling, manufacturing process modelling and component or system design. Such an approach allows for location-specific mechanical properties within the same component, leading to significant weight-saving potential Specific fuel consumption (sfc) - a measure of the amount of fuel used by an engine per unit time per unit of thrust - usually expressed in pounds of fuel per hour per pound of thrust 32 Source: 33 Source: 34 Source: Page 25 of 58

27 5.3.3 Thermal Management and Energy Management Engine efficiency can be improved by minimising the proportion of air within the engine s core which is lost through seals, taken from the compressor for use as cooling in other parts of the engine, or taken from the engine for use in aircraft systems. The use of cooled cooling air, or the adoption of materials which do not need cooling at all, may offer opportunities for reduced CO 2 emissions from future engines. Advanced seal designs, such as circumferential carbon seals or air-riding carbon seals, can accommodate the variation of radial clearance over the engine s full operational range, and support improved thermal efficiency as a result Weight-Reduction Through Materials Technology Composite materials offer considerable potential for reducing engine weight. The use of polymer matrix composites (PMCs) is envisaged within the nacelle, fan system, shaft support structures and casings. Metal matrix composites (MMCs) may be suited to intermediate temperature compressor rotor applications, while the use of ceramic matrix composites (CMCs) in key high temperature areas may lead to weight reduction and improved thermal efficiency 36. Recent advances in manufacturing technologies will enable future engines to benefit from the weight-saving advantages of PMC fan-blades without compromising the aerodynamic efficiency levels achieved by today s metallic fan-blades. Further weight savings are achievable through the use of PMCs in the casing which surrounds the fan. Image: Rolls-Royce plc The use of high-strength MMCs in the compressor (see Figure 8), could enable the replacement of the traditional disc-and-blades arrangement with an integrally-bladed ring, resulting in weight savings of up to 70% 37 on those stages of the compressor to which it is applied. Figure 8 weight reduction opportunity in compressor discs, arising from the use of lighter, stiffer, stronger materials. From left to right: 1) disc with blades; 2) integrally bladed disc ( blisk ); 3) integrally bladed ring ( bling ) representing a weight reduction of some 70% versus 1) 37. Image Rolls-Royce plc The use of titanium aluminide as an aerofoil blade material offers the prospect of further weight reduction in compressor and low-pressure turbine areas 38, through a 50% reduction in blade material density 39. The lighter aerofoils can then be coupled with lighter discs, yielding further weight savings. 35 Source: 36 Source: 37 Source: 38 Source: Page 26 of 58

28 5.3.5 Advances in High-Temperature Materials Increasing the engine s thermal efficiency requires the development of materials or technologies enabling the engine s core to run at higher temperatures. Ceramic Matrix Composites (CMCs), currently under development, offer the potential for higher temperature capability (and hence increased engine thermal efficiency), reduced weight and reduced cooling requirements, the latter leading to further improvements in overall efficiency Advances in Manufacturing Technology Advanced joining processes such as solid-state friction welding, in which parts are rubbed together under very high loads to create a single fused component, enable reductions in weight compared with traditional joining methods 40. Developments in advanced measurement technologies such as computerised tomography and highspeed coordinate measurement machines support progress towards higher performance products by enabling the verification of manufactured geometric features such as complex 3D surfaces and intricate cooling holes Fuel Efficiency Improvements the Evidence Base Improvements in Fuel Efficiency Already Achieved Analysis by IATA [IATA, 2010] has shown that global commercial airline fuel efficiency has improved by over 30% in the past two decades, saving over 400 million tonnes of CO 2 per annum at current activity levels, relative to the fleet efficiency in Advances in engine and aircraft fuel efficiency form a key element of improvements in airline overall fuel efficiency. Figure 9 illustrates progress made since 2000 in the fuel efficiency of new large engines, demonstrating significant advances relative to the baseline engine. Figure 9 fuel efficiency of successive generations of large jet engines relative to a year 2000 baseline, showing progress towards ACARE engine fuel efficiency target. 39 Source: 40 Source: 41 Source: Page 27 of 58

29 5.4.2 The Imminent Generation of Aircraft Aircraft representing the imminent generation of technology are already entering service or are currently offered for sale to the market. These are aircraft whose fuel efficiency characteristics are well-defined, as we discuss here. Their impact on CO 2 emissions from UK aviation over the next 2 to 3 decades will be substantial, as set out in section 5.6 below. We consider 3 distinct aircraft categories: In the Single-Aisle (SA) category the Airbus A320neo will deliver fuel savings of 15 per cent 42 versus its predecessor and will enter service in The Boeing 737 MAX will have percent lower fuel burn than current 737s 43 and will enter service later this decade. The Bombardier C Series will offer up to 20% fuel-burn improvement compared to inproduction aircraft in the same category at a distance of 500 nautical miles 44, and is due to enter service in In the Twin-Aisle (TA) category the A350 XWB will enter service in 2014 and will offer a 25 per cent step-change in fuel efficiency compared to its current long-range competitor 45. The Boeing 787 entered service in 2011 and uses 20 percent less fuel than today's similarly sized airplanes 46. In the Very-Large (VL) category the Airbus A380 entered service in 2007 and burns 17 per cent less fuel per seat than its nearest competitor 47. The Boeing Intercontinental is 16 percent more fuel efficient than the and is due to enter service in early The Freighter entered service in The Drive Towards Future Generations of Aircraft Recently the European Commission s High Level Group on Aviation Research has published a vision for aviation in 2050 [HLG, 2011], calling for a reduction in CO 2 emissions per passenger kilometre of 75%, a 90% reduction in NO x emissions and a 65% reduction in perceived noise emissions from flying aircraft. This vision, known as Flightpath 2050 is benchmarked against the capabilities of a typical new aircraft in 2000, and relates to the evolution of technological capability, rather than fleet-average fuel efficiency. The aviation industry is actively engaged in significant research programmes to develop and demonstrate technologies which will support improved fuel efficiency in future aircraft. Some examples include: The FAA s Continuous Lower Energy, Emissions and Noise (CLEEN) program has among its goals to develop and demonstrate by 2015 aircraft technology that reduces aircraft fuel burn by 33 percent relative to current subsonic aircraft technology 49. The E3E programme aims to demonstrate engine core technologies to enable a fuel-burn reduction of 15% relative to similar engines currently in service 50. The Strategic Investment in Low-carbon Engine Technology (SILOET) programme is expected to yield a 2% improvement in engine fuel economy, and is scheduled to complete in viewed 14 Feb viewed 14 Feb viewed 14 Feb viewed 14 Feb viewed 14 Feb viewed 14 Feb viewed 14 Feb Page 28 of 58

30 The ValiDation of Radical Engine Architecture systems (DREAM) project has the aim of advancing technologies which could collectively reduce specific fuel consumption by 27% 52. The EU s CleanSky Joint Technology Initiative is a 1.6 billion Euro aviation technologydevelopment program. Subprograms within CleanSky include: o Smart Fixed Wing Aircraft (SFWA) which aims to develop technologies enabling a 10% reduction in aircraft drag 53 o Sustainable And Green Engines (SAGE) which will include an open-rotor demonstrator, as well as a large 3-shaft engine demonstrator which will validate the lightweight low-pressure system developed within other programmes 54,55. o Green Regional Aircraft (GRA), demonstrating low weight structures and aerodynamic developments for regional aircraft 56. o Systems for Green Operations (SGO), demonstrating new architectures and technologies for electrical power generation, distribution, conversion and storage Aircraft Fuel Efficiency Assumptions Here we set out our assumptions concerning the fuel efficiency improvements, relative to their respective predecessors, of two successive generations of aircraft types. We consider in turn each of the three categories of aircraft (SA, TA, and VL) identified in section above Imminent Generation (G1) Aircraft In section above we presented the evidence base concerning the fuel efficiency of specific imminent aircraft types in comparison with their respective predecessors. For the purposes of our Road-Map, here we establish an average fuel efficiency improvement figure to employ in each of three aircraft categories, relative to the corresponding fleet-average fuel efficiency in This is shown in Table 4, alongside the entry-into-service date assumed within our Road-Map. We assume that the fleet 58 in 2010 was composed largely of the direct predecessors of the imminent aircraft types discussed above. Overall, this assumption may prove conservative, due to the presence of a number of older aircraft within the 2010 fleet, leading to a slight under-estimate of the fleet-wide CO 2 -mitigation potential arising from the adoption of G1 aircraft. However, in the case of the verylarge aircraft category, this assumption overlooks the small number of A380s already in service on UK routes by We do not believe the error introduced by this is material to the overall analysis. Category Single-Aisle Twin-Aisle Very-Large Entry into service of aircraft type Fuel efficiency improvement relative to predecessor aircraft types 13 % 20 % 17 % Table 4 assumed fuel efficiency improvement of imminent (G1) aircraft types relative to their respective predecessors Aircraft used on routes within, into or out of the UK. Page 29 of 58

31 5.5.2 Future Generation (G2) Aircraft Our assessment of the fuel efficiency of G2 aircraft in each of the three categories is derived with reference to the corresponding G1 aircraft, and is driven by three factors: the entry into service (EIS) date of the G2 aircraft type relative to its G1 predecessor; the rate of underlying improvement in aircraft and engine fuel efficiency through evolutionary developments in technology; any significant technologies or configurational changes which result in a step-change in aircraft fuel efficiency over and above the assumed underlying improvement trend. Clearly, when attempting to form a view of the likely capabilities of aircraft decades into the future, we must be aware of the significant uncertainty in any assessment. The following constitutes Sustainable Aviation s judgement concerning each of the above three bullet points, and should not be interpreted as a statement of intended product strategy. The decision to launch a new aircraft product is influenced not only by technology readiness but by many other factors such as the market demand, maturity of the in-service fleet, the prevailing economic situation, regulatory pressures and oil price predictions. 1. Starting with the first of the above three factors, our assumed EIS dates for G2 aircraft are as follows: Single-Aisle a value of 2025 is chosen to reflect a balance between several competing factors. Although this will be only some 10 years after the introduction of the G1 aircraft in this category, it is anticipated that technological developments by that time will warrant the introduction of a new aircraft type which is significantly more fuel-efficient than the G1 aircraft. Twin-Aisle we assume a gap of approximately years between G1 aircraft and their successors in this category, leading to an approximate EIS of Very-Large in this category we assume a gap of approximately 30 years between G1 aircraft and their successors, leading to an approximate EIS of Having established EIS dates in each of the three aircraft categories, we then assume an underlying rate of development in technologies applicable to all three aircraft categories. A value of 1.3% per annum is chosen based on a number factors: The recently observed fuel efficiency improvement rate of successive generations of aircraft. The strengthening commercial drivers related to increasing fuel-prices and carbon prices. The availability of increasingly capable computational analysis and design tools. This number is also broadly consistent with the underlying rate of improvement evident in the assessment presented by CAEP s Group of Independent Experts in [ICAO, 2011], as discussed in section below. 3. Finally we consider step-changes in efficiency arising from significant new technologies such as open-rotor engines, laminar flow aerodynamics and alternative airframe configurations. Single-Aisle since the G1 aircraft in this category is a re-engined version of its predecessor with largely the same airframe, the corresponding G2 aircraft will have the opportunity to incorporate two generations of developments in airframe technology. Only part of this opportunity will be captured in our representation of the underlying technology development rate. The adoption of advanced ultra-high bypass ratio engines for example open rotors - is also considered likely, together with other significant technology changes. To encompass all three of these factors we assume in this category a step change of 15% over and above the underlying technology development rate. Page 30 of 58

32 Twin-Aisle we anticipate that the use of open rotor engines in this aircraft category is less likely than in the single-aisle category. We also note that the transition from G1 to G2 aircraft will offer the opportunity to advance by one generation of airframe technology, rather than two generations as assumed for single-aisle aircraft. However, taking into account that the impact of fuel efficiency improvements upon mission fuel-burn is greater for longer flights (as discussed in more detail in Appendix E below), and taking also into account the stronger case for the adoption of fuel-saving technologies on larger, longer range aircraft for which fuelrelated costs are arguably more significant relative to purchase cost, we also assume a stepchange of 15% in this category. Very-Large for similar reasons we assume a step change of 15% in this category. Table 5 shows the outcome of applying the above assumptions to each of our three aircraft categories, detailing the fuel efficiency of G2 aircraft relative to their respective G1 predecessors. Category Single-Aisle Twin-Aisle Very-Large EIS of aircraft type Fuel efficiency improvement relative to equivalent G1 25 % 38 % 45 % aircraft type 59 Table 5 assumed fuel efficiency improvement of future (G2) aircraft types relative to their respective predecessors Figure 10 illustrates the assumptions set out in the preceding paragraphs concerning the fuel efficiencies of future (G2) aircraft in each of the three categories single-aisle, twin-aisle and verylarge, relative to their respective G1 predecessors. The capabilities of G2 aircraft are determined with reference to the improvement curve and step-change contributions described above. Figure 10 Technology development curve used to calculate the assumed fuel efficiency of G2 aircraft types relative to that of their respective G1 predecessors. Note that the efficiency of new aircraft (shown in this chart) is distinct from the evolution of fleet-average fuel efficiency (not shown on this chart) which is also influenced by fleet turnover rates. 59 Values rounded to the nearest whole percentage point Page 31 of 58

33 5.5.3 Comparison with CAEP Fuel Efficiency Assumptions In 2011, ICAO s Group of Independent Experts (IEs) published a report [ICAO, 2011] exploring the prospects for advances in fuel efficiency of new aircraft in 2020 and in The report considered a number of technology scenarios (labelled TS1, TS2, TS3, and TS3-OR, in order of increasing ambition) and their potential for improving the efficiency of aircraft types corresponding to the singleaisle and twin-aisle categories used in this Road-Map 60. The IEs also recommended a target range of efficiency improvement corresponding to a band lying between the TS2 and TS3 scenarios. Figure 11 shows, for these two aircraft categories, our technology development assumptions set within the context of the IEs technology scenarios and recommended target range, expressed relative to the fuel efficiency of the corresponding G1 aircraft. With reference to the single-aisle chart within Figure 11, it should be noted that the announcements by both major aircraft manufacturers concerning the offering to market of re-engined rather than all-new single-aisle aircraft post-date the IEs analysis. In arriving at their conclusions the IEs chose not to take account of a number of step-change technologies, including engine water-injection, turbofan intercooling, blended-wing-body aircraft configurations and ultra-high bypass ratio turbofan engines. However, open-rotor engines (10% reduction in fuel-burn) and hybrid laminar flow control (10% reduction in drag) were identified as having potentially large benefits. The TS3 scenario (representing the more aggressive end of the IEs proposed fuel efficiency target) contemplates modest changes in aircraft configuration and mission specifications such as range or cruise speed Freighter Aircraft Figure 11 comparison of assumed technology improvement rates against technology scenarios identified by the CAEP Group of Independent Experts (IEs), showing Single-Aisle (left diagram) and Twin-Aisle (right diagram) categories. In recent years, sales of OEM freighter aircraft have become increasingly significant relative to the traditional market for freighters converted from former passenger aircraft. This phenomenon, driven largely by the very significant increases in fuel prices witnessed in the past decade, lends support to SA s belief that the fuel efficiency of the freighter fleet as a whole will improve no less quickly than that of the passenger fleet. We do not therefore attempt to model separately the evolution of freighter fleetaverage fuel efficiency. Since the proportion of UK-departing tonne-kilometres carried on freighter aircraft is relatively small in comparison with that carried on passenger flights (see section 2 above) we do not believe that our assumptions will introduce any significant error to the overall analysis. 60 The fuel-burn reduction potential within the very large category was considered by the IEs to be not significantly different to that in the twin-aisle category Page 32 of 58

34 5.6 Impact on Fleet-Average Fuel Efficiency In section 5.5 above, we set out our assumptions concerning the fuel efficiency and entry into service timescales of imminent (G1) and future (G2) aircraft types. In this section, we address the issue of fleet-turnover (the rate at which new aircraft types replace older aircraft in service), and show the resulting impact of these aircraft upon fleet-average fuel efficiency in 2050, taking into account the relative importance of the three aircraft categories (SA,TA and VL) within the overall fleet fuel-burn distribution. Appendix A presents our assumptions concerning the speed of fleet-turnover, whilst Appendix B details the relative importance with the UK aviation fuel-burn mix of the three categories of aircraft. The relevant figures are summarised in Table 6. Aircraft Category: Single-Aisle Twin-Aisle Very-Large Share of Total UK Aviation Fuel-burn 61 31% 42% 27% Fleet turnover 62 period Imminent (G1) aircraft 30 years 25 years 20 years Future (G2) aircraft 25 years 20 years 20 years Table 6 Relative significance of single-aisle, twin-aisle, and very-large aircraft within UK aviation s fuel-burn, and the fleet-turnover periods of successive generations of aircraft in those same categories For the purposes of our Road-Map, we have adopted a simple linear fleet-transition model, meaning that a fixed proportion of the RPKs delivered in a particular aircraft category is transferred from old to new aircraft types during each year of the fleet-turnover period applying to that category. This transition is conducted independently of any underlying growth in total RPKs delivered. As a result the percentage CO 2 saving within that aircraft category, relative to the exclusive use of old aircraft, rises linearly throughout the fleet-turnover period, and can therefore, for any interim year, be calculated directly from a) the relative efficiencies of the new and old aircraft types and b) the proportion of the fleet-turnover period that has elapsed. To give a specific example, consider a 20-year fleet-turnover period within one of our three aircraft categories, in which the new aircraft is 10% more fuel-efficient per RPK than its predecessor. At the start of this period, all RPKs within that aircraft category would be delivered by aircraft of the old model. One year later, 5% of RPKs delivered within that category would be on the new model with the remainder being delivered by old model aircraft. The fuel saving at this point, relative to the exclusive use of old aircraft, would be 0.5%. 10 years after commencement of the transition, RPKs would be delivered 50% by old aircraft and 50% by new aircraft with a corresponding CO 2 saving (relative to the exclusive use of old aircraft) of 5%. In any particular year, the CO 2 saving across the entire fleet due to adoption of new aircraft in different categories, is simply the sum of the savings in each of the three aircraft categories, weighted by the relative importance of those categories Imminent Generation (G1) Aircraft Due to our assumptions concerning EIS dates and fleet-turnover periods, in our Road-Map all fleet transition from baseline to G1 aircraft will be complete by Adoption of G1 aircraft will therefore result in a fleet-wide CO 2 saving, due to relative to an all-baseline fleet, of 17%, as shown in Table See Appendix B 62 See Appendix A Page 33 of 58

35 Fleet turnover factor 63 Fleet weighting factor 64 Fuel-burn factor 65 Fuel-burn relative to preturnover total G1 aircraft Old aircraft Single-Aisle Twin-Aisle Very-Large CO 2 Saving 66 Combined % Table 7 relationship between aircraft fuel efficiency improvements (G1 vs baseline) and the resulting impact on fleet fuel efficiency in Future Generation (G2) Aircraft Our assumed EIS dates and fleet-turnover periods relating to the transition from G1 to G2 aircraft mean that fleet turnover for certain aircraft types will not be complete by However the method employed above is nonetheless applicable, and yields the values shown in Table 8. Fleet turnover factor 68 Fleet weighting factor 64 Fuel-burn factor 69 Fuel-burn relative to an all-g1 fleet G2 Aircraft G1 Aircraft Single-Aisle Twin-Aisle Very-Large CO 2 Saving 70 Combined % Table 8 relationship between aircraft fuel efficiency improvements (G2 vs G1) and the resulting impact on fleet fuel efficiency in representing completed fleet-turnover 64 Values representing percentage of fleet fuel burn, taken from Table 6 (31% represented as 0.31 etc) 65 Values taken from Table 4 (0.87 represents 13% improvement, etc) 66 Percentage saving in fleet-wide fuel-burn (and hence CO 2) relative to an all-baseline fleet 67 Summation of fuel-burn on new aircraft, and any remaining old aircraft, in the three aircraft categories. 68 Values derived from a) EIS date given in Table 5, and b) fleet turnover period given in Table 6 69 Values taken from Table 5 (e.g represents 25% fuel-efficiency improvement relative to the G1 predecessor) 70 Percentage saving in fleet-wide fuel-burn (and hence CO 2) relative to an all-g1 fleet 71 Fleet turnover is assumed complete in this category by 2050, so fuel-burn taking place on instances of the G1 aircraft is zero Page 34 of 58

36 6 Sustainable Fuels SUMMARY We estimate that by 2050 sustainable fuels will offer between 15% and 24% reduction in CO 2 emissions attributable to UK aviation. This assumption is based on a 25-40% penetration of sustainable fuels in to the global aviation fuel market, coupled with a 60% life-cycle CO 2 saving per litre of fossil kerosene displaced. For the purposes of our Road-Map, we assume an 18% reduction in CO 2 emissions from UK aviation through the use of sustainable fuels. 6.1 Introduction Sustainable biojet 72 fuel (biojet) could play a vital role in reducing the carbon footprint of UK aviation and the industry has been working on a range of initiatives to develop this opportunity. In Europe a project has been launched to deliver annual production of 2 million tonnes of aviation biofuel by Support from the UK government, similar to that given by other countries, will be necessary to make this a reality. Unlike ground transport or power generation, aviation is dependant on liquid hydrocarbon fuels for the long-term and therefore the development of aviation biojet fuels to meet this need should be a priority of government policy. The limited amounts of sustainable biomass (for biofuels) available worldwide should be designated primarily for those sectors that do not have alternatives. Aviation is one such sector. For road transportation, other than heavy goods vehicles, alternatives exist and these should be further developed and stimulated. We believe that biojet can potentially account for 40% of aviation fuel use by airlines operating out of the UK, as stated in the EU white paper on the future of aviation 74. With a 60% improvement in lifecycle emissions, CO 2 emissions would therefore be reduced by up to 24% as a result of biojet. Biojet will be a global commodity, and accounting based on purchases of biojet will enable airlines to claim emissions reductions, regardless of where in the world the biojet enters the supply chain. Sustainable biojet fuels must satisfy strict criteria concerning suitability, sustainability and scalability, as described in more detail in section 6.3 below. 6.2 UK Initiatives A number of UK airlines are leading the way in supporting the development of sustainable aviation fuels. Learning from mistakes made with earlier generations of biofuels aimed at other industries, these airlines have worked together to support the uptake of robust sustainability principles for aviation biofuels. British Airways and Virgin Atlantic are founding members of the Sustainable Aviation Fuel Users Group (SAFUG 75 ), established in 2008, which now has 20 other airline members (including Thomson Airways) and accounts for about 25% of worldwide aviation fuel demand. SAFUG actively supports the Roundtable on Sustainable Biofuels (RSB 76 ), which defines 12 key sustainability principles that suppliers must meet in order to become RSB certified. 72 In this chapter we use the terms biofuel or biojet to refer not only to fuels produced from biomass, but also to fuels derived from various waste streams, including solids (e.g. municipal waste), liquids (e.g. used cooking oil) and gases (e.g. waste gases from industrial facilities) See also Directive 2009/28/EC (Renewable Energy Directive) Page 35 of 58

37 British Airways, in partnership with the Solena Group, is to establish Europe s first sustainable jet-fuel plant and plans to use the low-carbon fuel to power part of its fleet from The new fuel will be derived from waste biomass and manufactured in a state-of-the-art facility that can convert a variety of carbon-based feedstocks, destined for landfill, into aviation fuel. Virgin Atlantic s partnership with LanzaTech will see waste carbon monoxide gases from industrial steel production facilities captured, fermented into ethanol using a naturallyoccurring microbe, and chemically converted for use as jet fuel. The new process utilises gases normally flared off into the atmosphere as carbon dioxide effectively recycling the carbon and producing fuel with around half or less the carbon footprint of kerosene. Virgin Atlantic plans to use the fuel in commercial flights out of Shanghai from 2014, and ultimately hopes to bring the technology to the UK. In October 2011 Thomson Airways was the first UK airline to fly customers on sustainable biofuel on flight TOM 7446 from Birmingham to Arrecife. Daily operations will start from early 2012 for approximately six weeks. Airbus is taking a leadership role with British Airways and Virgin Atlantic towards delivering the 2 million tonnes of biofuel mentioned above. 6.3 Sustainability Aviation is a global industry with flights crossing borders each day, therefore harmonised and consistent sustainability standards between and within regions will foster better practice within the biofuel sector and enable aviation s use of such fuel. SA is committed to strong sustainability principles [SA, 2010b], consistent with those of the Sustainable Aviation Fuel Users Group, to ensure biojet will: not displace or compete with food crops or cause deforestation; minimise impact on biodiversity; produce substantially lower life cycle emissions than fossil fuels; be sustainable with respect to land, water and energy use; deliver positive socioeconomic impacts. Commercial scale sustainable aviation fuels employed by SA member airlines will meet sustainability standards consistent with and complementary to internationally recognised standards such as those being developed by the Roundtable on Sustainable Biofuels. Life-cycle CO 2 emissions associated with biofuel use are influenced by such factors as the type of feedstock, the processing route through which feedstock is turned into fuel, and any direct or indirect land-use change which arises from the feedstock cultivation. Figures ranging between 10-95% CO 2 saving from different feedstocks are frequently quoted 77. These generally do not include indirect land use change (ILUC) impacts, i.e. where crops for biofuels are grown on agricultural land, displacing other crops. In general, the criterion of 50% reduction in life-cycle GHG emissions is currently accepted as the yardstick for a sustainable biofuel. European regulations for classification of biofuel 78 are expected to increase the life-cycle requirement to 60% for all new biofuel plants from January 2018, and hence we have assumed 60% life-cycle CO 2 emissions savings for biojet in this Road-Map. 77 It should also be noted that biojet will generally have a much lower sulphur content than current aviation fuels and that associated emissions of particulates will be lower, thus contributing to improvements in air quality around airports. 78 Communication 2010/C 160/ Page 36 of 58

38 6.4 Overview of Sustainable Fuel Categories Currently two types of biojet are certified for use in aviation jet engines, blended with kerosene: Synthetic Fischer-Tropsch (FT) based kerosene produced through high temperature biomass gasification. FT kerosene is produced via biomass gasification followed by gas cleaning and synthesis over appropriate catalysts and already today is approved for use in a 50% blend. Hydro-processed Esters and Fatty Acids (HEFA), originating from plant, algal and microbial oils. In the absence of technical restraints, market forces and legislation are the main drivers for oil and fat selection. Algal oils can also replace vegetable oils in HEFA or similar processes, but these will not be commercially available for around 5 years. Algal oils have attracted significant interest from the aviation sector despite the very high infrastructure cost for industrial scale cultivation. The conversion of cellulosic and sugar based materials to biojet via the production of alcohols is in advanced stages of testing and is expected to be in commercial production by Pyrolysis technology is under development and our current view is that it will likely become available towards the end of the decade. Many biofuel demonstration flights have taken place since 2008, the majority making use of HEFA blended with conventional kerosene. Rigorous lab-testing and ground-testing have already led to the approval for commercial use of FT and HEFA biofuels blended in a 50% ratio with conventional kerosene. Certification is expected also for fuels such as alcohol to jet. 6.5 Economics of Biojet For regular commercial use, biojet must become economically viable and cost-competitive over the long-term compared to kerosene from fossil fuel sources. In the short-term, many biojet production processes are not economic and carry material first-of-a-kind risks for investors. Government policy should be targeted at reducing the investment risks and early commercial uncertainties. Given the need to accelerate long-term sustainable options, there is a case for introducing temporary, nondistortive policy support and risk management approaches that will stimulate the market for biojet. The first step should be to create conditions commercially attractive for producers to invest in biojet production and to sell it at prices competitive with kerosene. This would lead to accelerating cost efficiencies through economies of scale and technological development through learning. In the long-term, biojet is expected to become competitive due to a number of factors, including: Expected increase in fossil fuel prices, due to both demand and supply pressures. Application of carbon pricing in global economies, with increasing costs of carbon. Reducing biojet unit production costs due to economies of scale and technology learning. Lower feedstock costs. Reduced capital costs. While the time scales of development and penetration of biojet for aviation are still uncertain, government support will nonetheless bring forward the point at which biojet can compete effectively, i.e. both biojet and oil-based fuel will be offered to end consumers at similar prices (see Figure 12). Page 37 of 58

39 Costs and prices Fossil jet price + carbon cost p Fossil jet price Biojet production costs t now t 1 Time Point at which biojet becomes costcompetitive, without intervention Figure 12 - Economics of biojet - At the current time (t now) biojet production costs are higher than fossil kerosene prices, even if the carbon costs of the fossil fuels are included. Over time, a combination of scale and technological development is expected to reduce the production costs of biojet, while fossil kerosene prices and carbon costs are expected to increase. Without government support, biojet would not become cost-competitive with fossil kerosene until point t Scale-Up and Deployment One of the biggest impediments to large scale use of biojet is the dearth of capital to fund scale-up and rollout of the technology. This is often the most challenging stage in the development of a new industry, when the level of capital required increases significantly (compared to early research and technology demonstration), but significant commercial risks remain. However, some biofuel technologies such as FT-SPK and HEFA are already at scale-up and deployment stage. Existing policy mechanisms in the UK and Europe, such as the EU Renewable Energy Directive (EU RED) are currently insufficient to support the development of aviation biojet, and some are providing a disincentive for producers to invest in biojet production. Biofuel producers are making capital investment decisions based on present Government policy, which prioritises heat, power and road transport fuels. As a consequence, capital investment for renewable energy technologies is currently being spread across those sectors at the expense of aviation. There is a clear need for governments to provide appropriate positive incentives and support, for example through the provision of loans and loan guarantees. This could be structured in ways to unlock private sector sources of capital. One possible policy measure is that aviation biojet suppliers should qualify for tradeable certificates within incentive regimes provided for by national applications of the EU RED, such as Renewable Transport Fuel Certificates in the UK. From 2012, with the inclusion of aviation in the EU ETS, the cost of carbon will be added to the cost of buying fossil kerosene. These costs are likely to increase over time. Aircraft operators will be able to mitigate their exposure to the EU ETS by using biojet instead of fossil kerosene. As the price of carbon increases, this will provide an increasing financial incentive for the take-up of biojet, although for the foreseeable future the price of carbon will only give a modest incentive compared to tradeable certificates for production associated with the EU RED. 6.7 European Advanced Biofuels Flightpath The European Commission, Airbus, and high-level representatives of the aviation and biofuel producers industries, including UK-based airlines involved in SA, have joined forces to develop the Page 38 of 58

40 European Advanced Biofuels Flightpath 73 to promote production, distribution, storage and use of sustainably produced and technically certified biofuels. The aim of the initiative is the commercialisation of sustainably produced paraffinic biofuels in the aviation sector, by reaching 2 million tonnes of consumption by This objective from EC DG Energy is complemented by a target from EC DG Move of 40% renewable low carbon fuels for aviation by Assessment of Potential Mitigation Impact Based on the significant developments in the alternative fuels arena which have taken place since our first Road-Map was published, and with over 1000 commercial flights by European airlines using biofuel, we now estimate that significant deployment of aviation biofuels in commercial flights will commence around 2015 rather than around 2020 as previously assumed. Given the need to develop long-term sustainable fuel solutions and the rapid shift in support from many governments around the world, we are optimistic that the challenges related to the required sustainability and scalability of these fuels can be overcome with government support. The extent of progress made over the past three years, particularly with respect to diversification of potential feedstocks and processing routes, leads us to a more optimistic assessment of biojet s potential than was adopted in our 2008 Road-Map. Furthermore, recent research such as that described in [PARTNER, 2010] has highlighted the potential for biofuels to achieve higher life-cycle carbon savings per litre biofuel than was previously supposed in our 2008 Road-Map. Consequently, we estimate that, by 2050, sustainable fuels could offer between 15 and 24% reduction in CO 2 emissions attributable to UK aviation by This assumption is based on a 25-40% penetration of sustainable fuels into the global aviation fuel market, coupled with a 60% life-cycle CO 2 saving per litre of fossil kerosene displaced. Our deployment estimate is somewhat higher than the suggested estimate for planning of around 10% penetration made in [CCC, 2011]. However, the same report also presented alternative scenarios in which the level of sustainable fuel penetration in UK aviation was considerably higher than 10%, particularly in a world without carbon capture and storage 80. For the purposes of our CO 2 Road-Map, from within the range of 15-24% set out above, we take as our central estimate an 18% reduction in CO 2 emissions from UK aviation through the use of sustainable fuels CCS has not been incorporated in our present analysis, but will be considered for possible incorporation when the Road-Map is next updated Page 39 of 58

41 7 Carbon Trading SUMMARY although the aviation industry will continue to make significant reductions in its own carbon intensity, a global carbon trading scheme will be required to enable aviation to contribute to overall carbon reductions beyond those achievable within the industry itself. We emphasise that international aviation requires a global approach in order to avoid market distortions and carbon leakage. The global aviation industry has set out a goal for aviation to reduce its net emissions in 2050 to 50% of levels in 2005 through participation in carbon trading. In this Road-Map we illustrate the extent of carbon trading required to allow UK aviation to achieve the same goal. 7.1 Introduction As discussed in the preceding sections, the aviation industry expects to make very significant reductions in its carbon intensity over the next few decades through a combination of operational improvements, advances in engine and aircraft technologies, and the adoption of sustainable fuels. Nonetheless, the value of aviation to society and the economy is such that, in the international context, strong growth in demand is likely to result in an increase in absolute CO 2 emissions from global aviation. Further reduction in global aviation s CO 2 emissions can best be addressed through establishing global net emissions reduction targets within a carbon trading policy framework. Carbon trading, implemented properly, delivers certainty in reductions of emissions as opposed to the uncertainty of taxes and charges. Carbon trading is by far the most effective economic instrument to reduce net emissions in the aviation sector. The UK Government has long recognised that some sectors of the economy will be able to reduce emissions more cost-effectively than others, hence the need for a cap and trade solution. The EU ETS, implemented in a manner that does not distort air transport markets and avoids international dispute, can be a first step towards a global carbon trading solution. 7.2 The Need for a Global Approach There is no climate impact of international aviation that can be confined to the UK. Emissions from the aviation sector which impact the global climate must be addressed at a global level, through appropriate international bodies such as ICAO. The UK government should continue to support work through such international organisations to achieve effective international measures, in particular trading, while working to ensure that international aviation emissions are excluded from national emissions inventories. We strongly oppose including international aviation in the UK carbon budget or introducing national targets or measures aimed at reducing international aviation emissions. If international aviation were included in the UK budget, this would lead to perverse policy decisions that would not reduce global emissions, but would only give the illusion of a reduction in UK emissions. For this reason we support the drive for a global sectoral agreement to regulate CO 2 emissions from international aviation. 7.3 Assessment of Potential Mitigation Impact In a carbon trading framework, the level of mitigation will ultimately be set by regulators. We believe that targets should be established at the international level in line with relevant scientific evidence. Globally, policy should be coordinated on a pathway towards a global target for aviation within a carbon trading framework which would complement technological developments, operational improvements and the use of sustainable fuels. Page 40 of 58

42 We believe that the appropriate target for international aviation is to reduce overall net emissions by 50% by 2050 relative to 2005 levels. This target has been proposed by all major elements of the international aviation industry [ACI, 2009]. In this Road-Map, our assumed trajectory of net CO 2 emissions from UK aviation is composed of two elements: To reflect the emissions cap associated with the incorporation of aviation into the EU ETS, we assume a level of net CO 2 emissions from corresponding to 95% of CO 2 emissions from UK aviation in From 2020 onwards we assume a gradual reduction in net CO 2 emissions, reaching 50% of 2005 levels by The exact trajectory of this reduction remains to be determined by governments we have assumed a linear trajectory pending future clarity on this issue. Page 41 of 58

43 8 Summary of Assumptions 8.1 Demand Growth Table 9 summarises the emissions trajectory within our hypothetical no-improvements scenario, which represents growth in demand for aviation from 2010 to Year Emissions (% vs 2010) in a hypothetical no-improvements scenario Table 9 hypothetical no-improvements emissions trajectory assuming a constant level of technology, no change in operational procedures, and no biofuel adoption 8.2 Mitigation Assumptions Table 10 sets out a summary of our views concerning the potential for and likely extent of reductions in UK aviation s carbon intensity through a combination of improved operational practices, more efficient aircraft, and the use of sustainable fuels. Engine and Airframe Measure Fleet Carbon Efficiency Benefit (%) 81, Potential Assumed Potential Assumed ATM and Operations Imminent Aircraft Future Aircraft Sustainable Fuels TOTAL Table 10 impact of measures to improve carbon efficiency of UK aviation, by 2030 and taking into account extent of deployment by the specified date. 82 Values rounded to nearest 0.5% 83 Note that the total is not the arithmetic sum of the individual contributions, since each successive percentage reduction is in relation to what remains after the previous reductions have been taken into account. For instance a reduction of 50% followed by another reduction of 50% would yield a combined reduction of 75%. Page 42 of 58

44 9 The Sustainable Aviation CO 2 Road-Map SUMMARY based on our assumptions and analysis, we conclude that UK aviation is able to accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. 9.1 The Road-Map Having in previous sections set out the individual elements of our Road-Map and the assumptions that we have made, in this section we now combine these assumptions to produce the Road-Map itself. Figure 13 Sustainable Aviation CO 2 Road-Map, showing that UK aviation can accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. 9.2 Discussion Average Rates of Improvement Taken together, our mitigation assumptions combine to yield an average rate of improvement in fuelburn per tonne-kilometre (responsible for the uppermost of the three brackets on the right hand side of Figure 13) of some 1.44% per annum, of which an average of 1.21% per annum arises from the deployment of more fuel-efficient aircraft. When the impact of sustainable fuels is taken into account, the average annual rate of improvement in carbon intensity is 1.93%. The rate of improvement in fleet-average aircraft fuel efficiency (1.21% per annum) is rather lower than the assumed rate of improvement in the fuel efficiency of new aircraft (1.3% p.a. plus stepchanges) which we set out in section 5.5 above. There are two reasons for this: The average improvement rate in fleet-average fuel efficiency is calculated over the 40-year period 2010 to However, our Road-Map takes account of aircraft types entering service up to and including This means that the technological or product developments taking place post 2040 do not influence our Road-Map within the 2050 time-horizon. Our assumption of a 2035 entry into service (EIS) for the second generation (G2) wide-body aircraft, and a 2040 EIS for the G2 very-large aircraft, coupled with a 20-year fleet turnover Page 43 of 58

45 period in both cases, means that many G1 aircraft in these two categories will not have been replaced by The full impact on fleet-average fuel efficiency of the technology embodied in the G2 wide-body and very-large aircraft types will therefore not be realised until after Comparison of SA s Projection with DfT s CO 2 Forecasts As described in section 2.2 above, our CO 2 Road-Map takes as its starting point forecasts of demand growth based upon the Central scenario within [DfT, 2011], in which DfT s own forecasts of CO 2 emissions from UK aviation, and the underlying assumptions, are also set out. Therefore in this section we compare DfT s CO 2 forecasts and assumptions against those set out in this Road-Map. Figure 14 Comparison of SA s view of absolute and net emissions in relation to DfT s Central CO 2 forecasts Figure 14 demonstrates that SA s projection of absolute CO 2 emissions from UK aviation in 2050 is some 22% lower than that set out in the corresponding DfT CO 2 forecast. Table 11 presents a comparison of DfT s mitigation assumptions 84 against those employed by SA in this Road-Map. [DfT, 2011] SA CO 2 Roadmap 85,86 ATM and Operations 0 9 % Sustainable Fuels New aircraft efficiency improvement relative to % 8 % % 18 % to 2020 Various NB %, % WB % % NB 35 % % WB % Carbon Trading As required to reduce net CO 2 emissions to 50% of 2005 levels Table 11 Comparison of CO 2 mitigation assumptions responsible for the differences set out in Figure Corresponding to the Central scenario, as set out on page 82 of [DfT, 2011] 85 Values derived from Table 4, Table 5 and Table Values rounded to nearest whole percentage point 87 NB narrowbody aircraft, corresponding to the single-aisle category discussed in section 5 88 WB widebody aircraft, corresponding to the twin-aisle and very-large aircraft categories discussed in section 5 Page 44 of 58

46 DfT s view of the rate of improvement in fleet average fuel efficiency is set out in Table 3.4 of [DfT, 2011], in which a value of 0.9% per annum is shown for the Central case, covering the period 2010 to This compares with the corresponding value of 1.21% from our Road-Map. Reasons for the difference can be inferred from Table Comparison of SA s and CCC s Mitigation Assumptions [CCC, 2009] examined the potential for UK aviation to reduce its carbon intensity, identifying a trio of scenarios entitled Likely, Optimistic and Speculative. The range of mitigation levels used by the CCC across those three scenarios is compared in Table 12 with our own mitigation assumptions which we have used to assemble this Road-Map. With regard to the potential for sustainable fuels to reduce CO 2 emissions from UK aviation, it is clear that SA s position is considerably more optimistic than that of [CCC, 2009]. However, in relation to ATM and operations, and also with regard to advances in fleet fuel efficiency, the figures align fairly well. [CCC, 2009] did not consider the impact of carbon trading on net CO 2 emissions. [CCC, 2009] SA CO 2 Roadmap 85 ATM and Operations 6-13 % 9 % Sustainable Fuels % 8 % % 18 % Average annual improvement in fleet fuel efficiency to % p.a % p.a. Carbon Trading 2050 N/A As required to reduce net CO 2 emissions to 50% of 2005 levels Table 12 comparison of CO 2 mitigation assumptions set out in this CO 2 Road- Map against those set out in [CCC, 2009] 9.5 Conclusions This document has set out Sustainable Aviation s projection of future CO 2 emissions from UK aviation, taking account of the UK government s forecasts of growth in demand. We conclude that UK aviation is able to accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. Government will play a key role in supporting research and development in aerospace technology, encouraging the introduction of sustainable biofuels, delivering on infrastructure projects such as the Single European Sky initiative, and working with other countries to establish a global sectoral approach for regulating international aviation emissions based on carbon trading. We do not support unilateral UK targets and measures as they would be unnecessary and counter productive. Such measures would deliver no overall environmental benefit, but would result in carbon leakage, market distortion, and the loss of economic benefits to our international competitors. Recent and future developments in aircraft and engine technology will play a major role in reducing UK aviation s carbon intensity. We anticipate absolute CO 2 emissions will continue to fall post-2050 due to the ongoing penetration into the fleet of new wide-body aircraft types entering service from 89 As distinct from the fuel-efficiency of new aircraft Page 45 of 58

47 around 2035 onwards. The same technologies will also be deployed on a worldwide basis, with a correspondingly greater CO 2 mitigation impact. The potential for sustainable biofuels to reduce CO 2 emissions from UK aviation has increased dramatically over the past three years. During this period, two classes of sustainable fuel have been certified for commercial use, and there has been considerable diversification in the range of potential feedstocks and processing routes being developed. This area continues to develop rapidly. Improvements in air traffic management and operational procedures will also play a material role in reducing the carbon intensity of aviation in the coming decades. Delivery of the above will be contingent upon suitable levels of support from Government, which should: support the development of more efficient aircraft and engine technologies which will be deployed on a worldwide basis; support the development and large-scale deployment of sustainable aviation fuels offering very significant life-cycle CO 2 savings relative to conventional fossil-based fuels; work with international partners to enable more efficient air traffic management on nondomestic routes, within the context of increased capacity requirements; press for agreement on and support the implementation of a global carbon-trading solution encompassing all of aviation and ensuring a level playing field for all participants. Aviation is a globally interconnected industry and needs a global solution to address its emissions in a cost effective manner without introducing competitive distortions. Any unilateral targets and measures that attempt to limit UK aviation s emissions through capacity constraints or price-related demand reduction will lead to carbon leakage, market distortion and the loss of economic benefit to our international competitors. We do not support the inclusion of international aviation emissions in UK carbon budgets. Our Road-Map shows that such unilateral policy measures are not necessary and that UK aviation can accommodate significant growth to 2050 without a substantial increase in absolute CO 2 emissions. We also support the reduction of aviation s net CO 2 emissions to 50% of 2005 levels through internationally agreed carbon trading. Page 46 of 58

48 References [ACI, 2009] A Global Sectoral Approach for Aviation (ACI, CANSO, IATA, ICCAIA), presented to ICAO s High-Level Meeting on International Aviation and Climate Change, Oct [CAA, 2010] CAA Airport Statistics for [CANSO, 2008] ATM Global Environment Efficiency Goals for [CCC, 2009] Meeting the UK Aviation target options for reducing emissions to v8.pdf [CCC, 2011] Bioenergy Review December [DfT, 2007] UK Air Passenger Demand and CO 2 Forecasts (UK Department for Transport, Nov 2007) passdemandfullreport.pdf [DfT, 2011] UK Aviation Forecasts (UK Department for Transport, Aug 2011) [GbD, 2003] [HLG, 2011] [IATA, 2010] [ICAO, 2003] [ICAO, 2009] [ICAO, 2010] [ICAO, 2011] Air Travel Greener by Design: The Technology Challenge The Tech Challenge.pdf Flightpath 2050: Europe s Vision for Aviation (High Level Group on Aviation Research, April 2011) Aviation and the Environment (presentation at 66th AGM) Operational Opportunities to Minimize Fuel Use and Reduce Emissions (Circular 303-AN/176, International Civil Aviation Organization, February 2003) Declaration of the High-level Meeting on International Aviation and Climate Change (HLM-ENV/09) Resolution A37-19: Consolidated statement of continuing ICAO policies and practices related to environmental protection Climate change Report of the Independent Experts on the Medium and Long Term Goals for Aviation Fuel Burn Reduction from Technology (ICAO Document 9963) [Lackner, 2009] Capture of Carbon Dioxide from Ambient Air (Eur. Phys. J. Special Topics 176, , (2009)) [NAEI, 2011] UNECE Emissions Estimates to 2009: Carbon Dioxide as Carbon (National Atmospheric Emissions Inventory, March 2011) [OE, 2011] Economic Benefits from Air Transport in the UK (Oxford Economics, 2011) Page 47 of 58

49 [PARTNER, 2010] [Poll, 2009] Life Cycle Greenhouse Gas Emissions from Alternative Jet Fuels (Stratton et al) The Optimum Aeroplane and Beyond (The Aeronautical Journal, Vol. 113, No. 1140, Mar 2009) [SA, 2008a] Sustainable Aviation CO 2 Roadmap, Dec [SA, 2008b] Non-CO 2 climate change effects of aviation emissions (Sustainable Aviation, Nov 2008) [SA, 2009] Sustainable Aviation Progress Report [SA, 2010a] [SA, 2010b] Aircraft on the Ground CO 2 Reduction Programme pdf Sustainable Alternative Fuels Progress Paper pdf [SA, 2011] Sustainable Aviation Progress Report [SESAR] The Future of Flying Page 48 of 58

50 APPENDIX A Fleet Turnover Assumptions Introduction In this document we use the term fleet-turnover period to refer to the number of years, following the entry into service of a new aircraft type in a particular category 90, before the fuel-burn taking place on the remaining examples of the older aircraft type within the same category, on routes falling within the scope of UK aviation, is considered no longer material to this analysis. We emphasise the distinction between this definition (based on the distribution of fuel-burn between older and newer aircraft types within the same category) and an alternative definition which might be based on the number of instances of the older aircraft type still in service. Our motivation for making this distinction is based on the observation that older, less fuel-efficient aircraft types will typically be used less intensively than their more fuel-efficient successors, and so will have less of an influence on total fuel-burn. Generation 1 (G1) or imminent aircraft Single-Aisle 91 although significant numbers of orders have been placed for the re-engined G1 aircraft from Boeing and Airbus, the order backlog is such that examples of the current generation aircraft will nonetheless continue to enter service for a number of years. The point at which fuel-burn within the remaining fleet of current generation aircraft is no longer material in comparison with that taking place on the G1 fleet will be correspondingly further into the future. We therefore estimate a 30-year fleet turnover period for this category 92. Twin-Aisle 93 in this category, although the Boeing 757 is no longer in production, the combined order backlog for other existing types - such as the Boeing 767, Airbus A330 and Boeing is very significant. However, the operating costs of aircraft in this category are arguably more sensitive to fuel-related elements than in the single-aisle category. Coupled with the greater percentage efficiency improvement offered by the G1 types in this category versus their respective predecessors (compared with that in the single-aisle category), this suggests a swifter transition towards the newer types. We therefore assume in this category a 25-year fleet-turnover period. Very-large 94 - we assume that, from now on, all examples of aircraft entering service on routes which depart from UK airports will be of the G1 types rather than the previous type. Given the significant fuel-burn benefits of the newer types over their predecessor we assume a fleet-turnover period of 20 years in this category. Generation 2 (G2) or future aircraft Single-Aisle based on our assumed entry-into-service (EIS) date 95 of G2 single-aisle aircraft types, it is likely that production of the G1 single-aisle aircraft types will still be in progress at that point. However, since the percentage improvement in fuel efficiency of the G2 single-aisle type versus its G1 predecessor is assumed to be much more significant than that of the G1 aircraft versus its corresponding baseline aircraft, we take the view that the fleet- 90 Single-aisle, twin-aisle, or very-large 91 This category includes such aircraft as the Airbus A320neo, the Boeing 737 MAX and the Bombardier C Series 92 The sensitivity of the overall fuel-burn estimate to variations in the fleet-turnover period in the narrow-body category is fairly low due to the small proportion of UK aviation fuel-burn that takes place on aircraft in this category (see Appendix B for more details). 93 This category includes the Boeing 787 and the Airbus A350 XWB 94 This category includes the Airbus A380 and the Boeing Discussed in section 5.5 of the main document Page 49 of 58

51 turnover period for introduction of the G2 aircraft will be shorter than that for the introduction of the G1 aircraft. We therefore assume a 25-year fleet-turnover period from G1 to G2 aircraft in this category. Twin-Aisle our assumed EIS date for the G2 twin-aisle aircraft type is some 20 years after the introduction of its G1 predecessor. We consider it unlikely that that there will be a significant overlap of production runs of G1 and G2 aircraft types. Furthermore, the sensitivity of this category to fuel cost will drive swift uptake of G2 aircraft to replace existing examples of the G1 predecessor. As a result we assume full fleet-turnover in this category within 20 years of EIS of the G2 aircraft. Very-large as with the twin-aisle category (and for the same reasons) we assume full fleetturnover in this category within 20 years of EIS of the G2 aircraft. Depending on assumed EIS date and fleet-turnover period 96, some aircraft categories may not have completed fleet-turnover from G1 to G2 aircraft types by 2050 in our model. 96 As set out in Table 6 within section 5 Page 50 of 58

52 APPENDIX B Distribution of Fuel-Burn This appendix sets out the distribution of aviation s fuel-burn between flights of different lengths and between different categories of aircraft. A summary is given in Table 13. Figure 15 illustrates the time-history of the UK distribution over the past few years. Looking specifically at 2010 data: Figure 16 shows the distribution of fuel-burn by flight-distance and aircraft category, both for UK and for global aviation. Whereas globally, fuel-burn is split roughly equally between narrow-body and wide-body aircraft, the majority of fuel-burn attributable to scheduled passenger flights which depart from UK airports takes place on wide-body aircraft on long-haul flights. Figure 17 shows how the wide-body fuel-burn is distributed between very-large and twinaisle aircraft categories. Although the analysis underpinning these figures is based on scheduled passenger flights only, due to a difficulty in sourcing data for charter and freight-only flights, we believe that this does not alter materially the conclusions concerning the dominance of the wide-body aircraft category within the fuelburn distribution on flights which depart from UK airports, and the approximately equal significance of narrow-body vs wide-body aircraft within global aviation s fuel-burn distribution. Aircraft Category Share of Fuel-Burn Flights which depart from UK airports Global Narrowbody Single-Aisle 31 % 51 % Widebody Twin-Aisle 42 % 38 % Very-Large 27 % 11 % TOTAL 100% 100% Table 13 summary of data presented in this appendix proportion of fuel-burn taking place within aircraft of different categories. Scope: 2010, scheduled passenger flights. Source Rolls-Royce analysis based on data from OAG. Figure 15 Distribution by aircraft category of UK fuel-burn on scheduled passenger flights, covering the years (based on actual data) and 2011 (based partly on anticipated schedules). NB = narrow-body; WB = wide-body 98. Source Rolls-Royce analysis based on data from OAG. Page 51 of 58

53 Figure 16 Distribution of fuel-burn on scheduled passenger flights in 2010 by aircraft category and distance. Scope: UK (left), Global (right). NB = narrowbody 97 ; WB = wide-body 98. Source Rolls-Royce analysis based on data from OAG 99,100. Figure 17 Distribution of fuel-burn on scheduled passenger flights in 2010, showing the distinction between very-large (VL) aircraft and twin-aisle (TA) aircraft. Scope: UK (left), Global (right). Source Rolls-Royce analysis based on data from OAG 99, Equivalent to the single-aisle aircraft category used in this document 98 In these charts, the wide-body (WB) category covers both twin-aisle and very-large aircraft. The distribution of fuel-burn between those two subcategories is shown later in this Appendix. 99 UK chart - fuel burn data cover 93.9% of OAG scheduled passenger data 100 Global chart - fuel burn data cover 94.7% of OAG scheduled passenger data Page 52 of 58

54 APPENDIX C Less Likely Mitigation Options In this appendix we review carbon-reduction options which do not feature in our current assumptions concerning UK aviation. Some of these options may become feasible in the future but we have chosen not to take account of them at present. Multi-Stage Long-Haul Travel The fuel required to raise an aircraft to its cruising height represents an overhead which has a particularly detrimental impact on the overall fuel efficiency (per kilometre) of shorter flights. Fuel efficiency on longer flights, on the other hand, suffers from the need to carry over significant distances not only a heavier fuel load but also the weight of aircraft structure required to contain the additional fuel. The balance or trade-off between these two effects gives rise to an optimum flight distance, at which fuel-burn per kilometre travelled is minimised. [GbD, 2003] gives a detailed discussion of the impact of design range on payload fuel efficiency. It concludes that, on a journey of 15,000km (around 8,000 nm 101 ), fuel-burn can in principle be reduced by almost 30% through employing an aircraft whose design range is 5,000 km instead of 15,000 km, taking the journey in three equal stages. In practice however, the likely reduction in fuel-burn arising from such measures is likely to be limited since there are many barriers to realising such savings in service: Referring to Figure 16 in Appendix B, we can see that the proportion of global aviation s fuelburn taking place on flights over 6000nm is relatively small. Furthermore, looking specifically at the distribution of fuel-burn on flights which depart from UK airports (also Figure 16) we can see that there is very little fuel-burn taking place on flights over 5500nm. The number of longrange flights over which significant fuel-burn savings could be achieved through a multi-stage approach is therefore extremely limited in the context of UK aviation. The savings possible through adopting a multi-stage approach to flights in the nm distance band would be eroded by competing factors such as increased time-related costs, or by increased journey distances arising from a lack of suitably placed interim airports, particularly on trans-oceanic or trans-polar routes. We do not at present consider that the adoption of multi-stage long-haul travel presents significant opportunities for genuine reductions in CO 2 emissions from UK aviation. Hydrogen as an Aviation Fuel The CO 2 emissions index of a fuel is usually defined as the ratio of the mass of CO 2 produced to the mass of the fuel burned. In the case of kerosene the value is Fuels with lower CO 2 emissions indices do exist, but in many cases are unsuitable for use as aviation fuels. One fuel which is often discussed as an alternative to kerosene in the longer term is liquid hydrogen. Liquid hydrogen produces no carbon dioxide at the point of combustion (in other words its CO 2 emissions index is zero), and might at first sight appear attractive as an aviation fuel from that perspective. In principle, if produced by electrolysis of water using low-carbon electricity, hydrogen could also benefit from a very low life-cycle carbon footprint. In practice however, unless electricity production is entirely decarbonised, the prioritisation of lowcarbon electricity for hydrogen production would likely displace other electricity demand onto higher- 101 Approximately equal to the distance from Chicago to Sydney, or from London to Perth. Page 53 of 58

55 carbon power generation. Alternatively, production of hydrogen from methane or other hydrocarbons is accompanied by the release of CO 2 which would need to be captured and sequestered to achieve a low life-cycle carbon footprint. From a practical standpoint, although hydrogen s energy per unit mass is almost three times that of kerosene, its energy per unit volume (even in liquid form) is only around one quarter that of kerosene. Fuel tanks would therefore need to be much larger to accommodate the greater volume of hydrogen fuel, and this has significant implications for airframe design. The requirement to operate parallel refuelling infrastructures during several decades of transition from kerosene to hydrogen would also increase costs and system complexity. We do not currently believe the use of hydrogen as a fuel for the primary propulsion of commercial aircraft is likely on a significant scale before Fuel Manufacture from Artificially Captured CO 2 The synthesis of hydrocarbon fuels by combining hydrogen (obtained through electrolysis) with artificially captured CO 2 has been proposed and is under development. However, the overall energy requirements for this process are such that arguably it would only be attractive once most other sectors have decarbonised and low-carbon electricity is in plentiful supply. We do not take account of any contribution from this approach within our current Road-Map. Sequestration of Captured CO 2 The direct capture of CO 2 from the exhaust of aircraft engines in flight is clearly impractical, since the weight of CO 2 produced by burning kerosene is some three times that of the fuel itself, whilst the size and weight of the equipment required to effect the capture would also be prohibitive. If aviation s CO 2 emissions are to be captured with a view to sequestration, the extraction must therefore be performed not from CO 2 -rich aircraft exhaust streams but rather from ambient air in which the CO 2 concentration is extremely low (around 0.04% by volume). Clearly, the absorption of CO 2 from ambient air is carried out on a large scale by growing plants. However, the permanence of sequestration associated with this form of capture is far from clear, being vulnerable to disruption through fire, logging or decay. An alternative mechanism for the capture of CO 2 from ambient air using an artificial device is proposed in [Lackner, 2009]. Such a device, if realised, could provide a stream of CO 2 suitable for permanent sequestration. However, much development work remains to be done to bring the concept to commercial reality. We do not take account of sequestration of captured CO 2 in our current Road-Map. Page 54 of 58

56 APPENDIX D Comparing the 2008 and 2012 Road-Maps Hypothetical No-improvements Scenario In our 2008 CO 2 Road-Map we based our hypothetical no-improvements scenario purely on growth in passenger numbers, based on DfT s 2007 passenger forecasts [DfT, 2007]. Although DfT s 2011 forecasts for passenger numbers [DfT, 2011] are noticeably lower than the corresponding figures from DfT s 2007 forecasts, in this 2012 Road-Map we are able to use what we believe is a more appropriate proxy for growth, namely a forecast of RPKs 102 delivered on passenger flights plus an estimate of FTKs 103 delivered on freighter aircraft. This migration, from a demand forecast based purely on passenger numbers to one which not only accounts for forecast changes in average distance flown but also incorporates growth in freight-only flights, results in an average rate of growth in demand for UK aviation which, during the period , is actually slightly higher than that assumed in our 2008 Road-Map, as Table 14 shows. ATM and Operations In this category, although the bottom-up analysis in the 2012 Road-Map (set out in section 4 above) is much more detailed than the simple top-down analysis used in the 2008 Road-Map, the results - relative to a common 2010 baseline - show fairly good agreement, as shown in Table 14. Engine and Aircraft Technology In this 2012 Road-Map we have split the aircraft fleet into three distinct categories, as described in the main text, and have based our assumptions concerning the improvement of fleet-average fuel efficiency within each category purely on the introduction of distinct aircraft types into the fleet. Improvements in fleet-average fuel efficiency in the early years are therefore based on the impact of the introduction of the imminent generation of aircraft types whose characteristics are known, rather than on some estimate of overall rates of improvement, as was used in the 2008 Road-Map. Due to recent changes in economic outlook, our assessment of the timescales over which future generations of aircraft will enter service now spans a more extensive period than that assumed in the 2008 Road-Map. The consequence of this is that, while our 2008 Road-Map anticipated the entry into service of two distinct future generations of aircraft, the second of these is now assumed to fall much nearer to 2050 than was previously assumed. Its impact on fleet-average fuel efficiency by 2050 is therefore considered not material to the analysis and as a result it is omitted altogether from the 2012 Road-Map. The significance of this change for fleet-average fuel efficiency is shown in Table 14. Sustainable Biofuels Our assessment of the potential for biofuels to reduce aviation s CO 2 emissions now benefits from greater clarity than was available at the time of our 2008 Road-Map. Since then, two types of aviation biofuel blend have been approved for commercial use, the range of feedstocks and processing routes under development has increased considerably, more detailed research has been undertaken to establish the life-cycle benefits of various types of aviation biofuels, and sustainability standards have been set. Our view is that the potential for aviation biofuel adoption is now considerably greater than was considered likely at the time of our 2008 Road-Map, as shown in Table RPKs = revenue passenger kilometres 103 FTKs = freight tonne kilometres Page 55 of 58

57 Carbon Trading In our previous Road-Map we chose not to represent the potential contribution of carbon trading to reducing UK aviation s net emissions, due to a paucity of relevant information. Since that time, details of aviation s incorporation into the EU ETS have been established, and the prospect of a global carbon trading system has strengthened considerably. In our 2012 Road-Map, we illustrate the level of carbon trading required to allow UK aviation to reduce net CO 2 emissions in 2050 to half of 2005 levels, in line with the global aviation industry s declared aspiration. Summary Edition of SA CO 2 Road-Map: Period Average demand-growth rate 2.32% p.a. 2.12% p.a. 2.32% p.a ATM / Operations 10% 7% 9% Reduction in Fleet Average Carbon Intensity in Aircraft and Engine 62% 56 % 39% Biofuels 10% 10% 18% Carbon Trading 0 0 As required to reduce net emissions to half of 2005 levels Table 14 comparison of assumptions used in the 2008 and 2012 Sustainable Aviation CO 2 Road-Maps 104 This column shown for context only 105 These two columns should be used as the basis for comparison 106 Values rounded to the nearest whole percentage point Page 56 of 58

58 APPENDIX E Impact of Fuel Efficiency on Mission Fuel-Burn Since a proportion of an aircraft s propulsive thrust is used to keep the aircraft aloft, any reduction in aircraft weight enables a reduction in required thrust, which itself enables a further reduction in weight arising from the reduced fuel requirement. This virtuous circle enhances the savings in mission fuelburn that can be achieved through the introduction of new technologies or operational procedures. Improving engine fuel efficiency, for example, means that less fuel is required to produce the same level of thrust. However, the thrust requirement is itself reduced because less fuel needs to be carried to achieve the same payload-range performance, and the aircraft as a whole is therefore lighter. In the context of a clean-sheet aircraft design, certain design choices then become available. Since achieving the desired mission requires less fuel, smaller and lighter fuel tanks can be specified, wings can be made smaller and lighter because less lift is required, and engines can be specified with a lower maximum thrust. These adjustments themselves reduce the thrust requirement even further. Improving aircraft aerodynamic efficiency can lead to a similar chain of additional effects reducing the aircraft s drag means that engine thrust requirements are reduced, leading to reduced fuel-burn and the potential for re-optimising the aircraft design as outlined above. The use of advanced materials or assembly methods resulting in a lighter airframe allows a similar story to be explored, as does the successful adoption of efficient operational procedures which reduce mission fuel-burn. The significance of this effect depends on the mission length for a longer flight the effects become more pronounced as the benefits of carrying less fuel accumulate over a greater distance. Since longhaul flights figure prominently in UK aviation s fuel-burn profile (as shown in Figure 16 within Appendix B), this effect is therefore of considerable relevance to this UK-centric CO 2 Road-Map. As an illustration of the significance of this effect, Table 15 presents indicative values - for a typical twin-engined wide-body airliner - of the impact on mission fuel-burn of improvements in engine fuel efficiency, with and without re-optimisation of the airframe configuration, at different mission-ranges. These figures, which do not assume any changes in airframe technology level, illustrate the significant benefits for long-range mission fuel-burn that be obtained through improvements in fuel efficiency. AIRFRAME CONFIGURATION UNCHANGED RE-OPTIMISED Approximate improvement in mission fuel-burn 108 Improvement in engine fuel efficiency % 20 % 10 % 20 % Trans-Atlantic 11 % 25 % 15 % 28 % Trans-Pacific 12 % 26 % 15 % 29 % Very long range 13 % 27 % 16 % 30 % Table 15 - indicative values, for a typical twin-engined wide-body airliner, illustrating the impact of engine fuel efficiency improvement on mission fuelburn, and its dependence on mission length. Note that these figures do not assume any changes in airframe technology level. 107 Improvement in specific fuel consumption (sfc), assuming no impact on nacelle geometry or engine weight 108 Source: Rolls-Royce model of a typical twin-engined wide-body airliner. Values rounded to the nearest whole percentage point Page 57 of 58

59 APPENDIX F ATM efficiency improvements in NATS airspace This appendix relates to section of the main document, and sets out how the ATM efficiency target adopted by the UK s air navigation service provider (NATS) will impact CO 2 emissions from flights which depart from UK airports. As stated in the main text, each flight within NATS control can be regarded as falling into one of four categories: overflights, domestic flights, inbound international, and outbound international. Notwithstanding the above categorisation, each flight can be regarded as consisting of a number of distinct phases: ground operations, climb, en-route, and descent. Not every phase of each flight will take place under NATS control, for instance the descent phase of an outbound international flight occurs elsewhere. Furthermore, not every flight under NATS control falls within the scope of our Road- Map, for example over-flights and inbound international flights do not originate from a UK airport and thus lie outside our scope. The NATS target refers to a reduction of CO 2 emissions from flights under NATS control by an average of 10% per flight, by 2020 relative to a 2006 baseline. CO 2 emissions from flights under NATS control in 2006 amounted to 25Mt. The target saving is therefore equivalent to 2.5Mt of 2006 emissions, although with growth in traffic to 2020 the target amount may increase. Total CO 2 emissions in NATS controlled airspace in 2006 from flights which departed from UK airports 109 are estimated by NATS at 12.3Mt. This includes 1Mt from airports (taxiing and take-off roll), 7.3Mt from domestic airspace 110 and 4.0Mt in North Atlantic airspace under NATS control. This 12.3Mt is 49% of NATS total baseline emissions of 25Mt in The climb phase of flight is known to offer one of the most significant opportunities for efficiency improvement because aircraft in this phase are at their heaviest with high thrust settings required to climb to more efficient cruise levels. Current airspace structures and air traffic flows also often require aircraft to level off and then to re-apply power in a stepped climb prior to reaching efficient cruise altitudes. Based on NATS analysis, we have assumed that improvements in climb efficiency account for four tenths of the NATS overall 10% improvement target, resulting in a reduction of 1.0Mt (relative to 2006 emissions) from improvements made in the climb phase of flights under NATS control. The entirety of this saving lies within scope of our Road-Map, and amounts to some 2.6% of UK aviation s total emissions in Further opportunities for reducing emissions through NATS ATM improvement are available in relation to the ground-operations, en-route and descent phases of flights. NATS estimates that the available saving relating to flights which depart from UK airports lies in the region of 0.5 MtCO 2 relative to the 2006 baseline. This corresponds to a further 1.3% of UK aviation s total emissions in We estimate therefore that total savings achievable on flights which depart from UK airports, as a result of successful delivery of the NATS 10% target, amount to 3.9% of UK aviation s CO 2 emissions. Although in the above analysis this saving is expressed relative to the stated 2006 baseline, the phasing of delivery is such that the vast majority will be achieved post We therefore take this 3.9% as being the available saving relative to the SA Road-Map s 2010 baseline, as we discuss further in section of the main document. 109 Only flights which depart from UK airports are within scope of our UK CO 2 Road-Map 110 Not to be confused with domestic flights 111 NATS baseline also includes emissions within NATS airspace from over-flights, and from inbound international flights Page 58 of 58

60 E: T: