Projects | ATSLAB

Market size and network effects of introducing the A321XLR in the transatlantic market

Introducing low-operating cost, very long-range narrowbody aircraft will allow airlines to operate intercontinental flights on a point-to-point basis rather than following the traditional hub-and-spoke model. Operating directly between lower-cost airports and being less susceptible to delays could lead to lower seat operating costs compared to widebody aircraft operating in a hub-and-spoke model, despite the smaller aircraft size. At the same time, a direct connection between smaller airports can increase passenger utility, particularly when avoiding transfers. Assessing the market size and network effects of introducing such aircraft thus requires a model that captures both supply and demand within a sufficiently high-resolution network. This study aims to quantify the market size and network effects of introducing the A321XLR in the transatlantic market (Europe / US) using the Airline Behaviour Model (ABM) developed at the UCL ATSLab.

Economic viability of hydrogen-powered aircraft on PSO routes in the European market

Public Service Obligation (PSO) routes could be a niche market, in which hydrogen aircraft experience a comparative cost advantage. The knowledge gained from smaller hydrogen-propelled aircraft could then be applied to larger aircraft types. Using ATSLab’s Airline Behaviour Model, this study assesses the economic business case of near-term hydrogen aircraft to serve existing PSO routes along with the required government support. It further examines the suitability of hydrogen aircraft for other network routes, estimates the related market size, identifies potential hydrogen hubs.

Towards Zero-Carbon Aviation (TOZCA)

Owing to the strong sector growth, the comparatively limited number of mitigation options and the long fleet turnover times, achieving zero-carbon emissions is particularly challenging for aviation. The EPSRC-funded “Towards Zero-Carbon Aviation” (TOZCA) project develops a comprehensive tool suite to simulate the most cost-effective transition towards a net zero-carbon aviation system by 2050 through changes in technology, fuels, operations, consumer behaviour and use of competing modes. TOZCA, which is led by the UCL ATSLab, is a collaborative effort with the University of Leeds, the University of Southampton, and the Massachusetts Institute of Technology. TOZCA also collaborates with around 20 stakeholders from industry, government, thinktanks and NGOs.

Liquid Hydrogen Gas Turbine (LH2GT)

The goal of the Rolls-Royce-led £31.4-million Liquid Hydrogen Gas Turbine (LH2GT) project, funded by the Aerospace Technology Institute, is to develop liquid hydrogen fuel system technologies for a hydrogen gas turbine engine. The ATSLab is contributing to a work package along with Rolls-Royce (lead), easyJet, and London Heathrow Airport to assess the economic viability of future hydrogen aircraft designs within the European market. Central to this activity is the ATSLab’s Airline Behaviour Model, which simulates the profit-maximising behaviour of competing airlines using segment flight frequencies, itinerary airfares, and route-based aircraft deployment as decision variables, thus reflecting the heterogeneity in the airline industry.

Modelling Aviation Global Climate Impacts from Contrails and Aerosols (MAGICA)

Aviation contributes about 5% to global climate change, with a significant portion caused by non-CO₂ effects. Among those, contrails and aviation-induced cirrus clouds have the largest uncertainty. Another important non-CO₂ effect is caused by aerosol-cloud interactions, for which, due to the substantial challenges to simulate it in models, no best estimates exist. This NERC-funded project, led by the University of Leeds, aims to reduce the uncertainty of these two non-CO₂ effects. To support this research, the ATSLab will generate three-dimensional, global emissions distributions for different fuel use scenarios (crude oil-based jet fuel, sustainable aviation fuels, and hydrogen) for input into climate models.

Contrails from SAF and H2 Combustion: from Lab Experiments to Global Mitigation Policy

Much of the non-CO₂ impact from aviation arises from the formation of contrails and cirrus clouds. Contrails are formed from water vapour condensing on soot particles (and other pre-existing particles in the atmosphere) and the subsequent freezing of water droplets and growth of ice particles. In ice-supersaturated regions, the contrails persist and eventually diffuse into cirrus clouds. The key objective of this NERC-funded project, led by Imperial College London, is to research the entire pathway from the combustion of different aviation fuels to contrail formation to global mitigation measures and policy recommendations. The ATSLab contributes to this research by modelling global aviation system scenarios under different CO₂ and non-CO₂ related policies to better understand the strategic use of synthetic, low-carbon fuels. Other project partners include the University of Leeds.

New Aviation, Propulsion, Knowledge and Innovation Network (NAPKIN)

Funded under the Phase 2 of the Industrial Strategy Challenge Fund’s Future Flight Challenge, NAPKIN brings together a range of UK aviation expertise to investigate the potential of electric aircraft for UK regional flights. By looking at different aspects of air travel – including aircraft, airports, airspace, airlines, passengers and communities – NAPKIN will help accelerate the introduction of sustainable, low and zero carbon commercial aviation. The project is led by Heathrow Airport Limited and includes a number of academic and industrial partners. Among those, Cranfield Aerospace, GKN and Rolls-Royce will develop conceptual designs for regional electric aircraft, while airport partners are using their expertise to assess the ground infrastructure implications. The ATSLab will assess the extent to which new technologies are commercially and operationally feasible across the UK regional aviation network, using the unique Airline Behaviour Model developed during the ACCLAIM project. This project is scheduled to start in November 2020.

Airport Capacity Consequences Leveraging Aviation Integrated Modelling (ACCLAIM)

Airport capacity expansions are among the most contentious policy decisions. Proponents for adding runway capacity point to the multiple economic benefits occurring at local, regional, and national levels. The converse is also correct – capacity constraints may lead to increases in airfares and changes in airline networks that take transit and origin-destination traffic away from the region, thus limiting growth in air traffic and the economy. In contrast, opponents to capacity expansions argue that unrestricted capacity growth would impact those living around airports via increased noise and reduced air quality, and the wider population via its contribution to climate change.

Currently, the world’s air transportation system experiences airport capacity expansion projects with a combined value in excess of $500 billion. However, there does not exist any tool that would rigorously evaluate the associated local, regional, and global-scale trade-offs. Building upon the Aviation Integrated Modelling (AIM) tool, the aim of the ACCLAIM project is to enhance the AIM tool to assess a wide range of implications from capacity expansion projects at any airport in the world. The ACCLAIM model will capture the complex relationships between airport capacity, technology, operational and fleet change and passenger demand in the short-, medium- and long-term, while dealing with the complex interplay of uncertainties at each level.

ACCLAIM’s key objectives for the refined and expanded model are to provide an independent capability:

• To model how competing airline alliances will respond to capacity constraints at any airport in the world over the short-, medium- and long-term via changes in airfares, flight frequency, use of equipage, and network structure.

• To model how passengers will respond to changes in airline supply, taking into account airfares; airport, airline, and itinerary choice; airline loyalty programs; etc., given other prevailing trends in the air transport sector such as the increasing share of low-cost airlines and the development of very long-range aircraft.

• To establish how the airline and passenger response to airport capacity constraints will interact to affect the wider airport and its hinterland in terms of economic impacts (accessibility, trade, tourism, etc.), environmental effects (noise, air quality, and climate impacts) and their associated costs, along with the economic costs of delaying airport capacity expansion (by quantifying lost passenger demand).

• To quantify how uncertainties at each point in the system impact system level outputs, including uncertainties in inputs (e.g., future income levels; fuel prices, as also related to biofuel adoption), business models (e.g., the prevalence of low-cost long-haul carriers), available equipment (e.g., long-haul aircraft), etc.

ACCLAIM further expands the already existing AIM capabilities of

• Modeling the integrated fleet level impact of new and changed aircraft and engine technologies, operational practices and fleet turnover in terms of environmental and economic performance, and

• Testing the system level effects of options for change in national or international regulation or fiscal and charging policy.

While the tool to be developed is applicable to any airport worldwide, it will be applied initially to the London airport system, where the UK Government plans to add capacity in the near future.

ACCLAIM is a joint project between University College London, Imperial College London, and the University of Southampton with inputs from the aviation sector, government, and NGOs. The three-year project, which started in the fall of 2015, is funded by the UK Engineering and Physical Science Research Council (EPSRC).

Systems Aspects of Electric Commercial Aircraft (SAECA)

(More) electric commercial aircraft show the promise of providing multiple benefits to air transportation. Because of their reduced dependence on oil, these benefits will be both economic and environmental. In particular, decreased noise levels and potentially faster turnaround times offer the prospect of increased airport capacity.

To date the majority of studies of more electric aircraft have focused on individual technologies and how they are integrated into a viable aircraft. These studies represent an essential first step, but it is important to recognise that aircraft operate within the wider context of an interconnected airport network.

The SAECA project will make a preliminary exploration of the electric airport network at an operational level and also consider how we transition from the airport of today to the electric airport of the future. This will require an analysis of operational, economic, energy, and environmental opportunities and challenges, within single type and mixed fleets.

This is a demanding challenge and the main aim of SAECA is set a clear roadmap for tackling it and bring together the right set of partners to solve it. SAECA will be reaching out to academics, industry and operators who will be kept informed of progress and invited to contribute at workshops.

It is funded by EPSRC through an Institutional Sponsorship Award to University College London, and performed in collaboration with the University of Southampton, the University of Cambridge, and the Massachusetts Institute of Technology.

Aviation Integrated Modelling (AIM)

Economic development, increasing global linkages, and continuously declining airfares have made air travel the sector of fastest growth amongst all transportation modes. Although, on average, aviation has become significantly more fuel-efficient over the last 40 years, the associated decline in fuel use per passenger-kilometer flown has been more than offset by the strong growth in travel demand. As a result, emissions of carbon dioxide and other greenhouse gases and precursors have continued to increase strongly. In light of the expected further growth in demand, the declining potential of mainstream technologies for increasing fuel efficiency will lead to a further strong growth in emissions. These growth trends require careful analysis to determine the potential implication of various policy tools (economic measures, aircraft technology, air traffic operation) on the environment and air transport system. In response to these trends, several important research programs, aiming at generating global air traffic emission distributions today and for the future were established during the past years both in the United States and Europe. At the same time, atmospheric scientists have been working largely independent from travel demand modelers and engineers. Not surprisingly, these isolated efforts create a number of difficulties when conducting integrated assessment of aircraft emissions.

This research aims to go beyond these isolated efforts and build a set of connected models, capable of performing integrated policy analysis. The highly modular system allows to easily exchange and test different model components for other research groups, government, and industry. Some components of the proposed model system are already operational as independent aircraft movement, local air quality, and global atmospheric models and need to be modified to function within the overall model system. Other modules need to be newly developed. Among those are an Air Transport Demand Module, which simulates the existing and projects future levels of passenger and freight traffic and its global distribution, and an Airport Activity Module, which simulates flight delays for take-offs and landings. Aircraft fuel use and emissions associated with the predicted transport demand are simulated by an Aircraft Technology Module. The estimated aircraft emissions along the respective flight trajectories are then fed into local air pollution and global atmospheric models to study regional and global environmental impacts.

The systems model offers vast opportunities for integrated policy analyses, ranging from economic measures (e.g. the introduction of various types of taxes) over technology measures (e.g. new engines with lower nitrogen oxide emissions) to operational measures (e.g. change in flight routings and cruise altitude) and their global and local atmospheric impacts. Compared to the existing isolated efforts described above, the in-house capability of all disciplines required for integrated assessment offers multiple advantages. These range from the possibility of including feedbacks between the model components to better understand trade-offs and develop optimum policies, enhanced information flow between modeling groups (associated with data needs, quality, and formats, research methods, etc.), and quick response time for policy analysis requests from government and industry. The three-year project, which started in the fall of 2006, is funded by the UK Engineering and Physical Science Research Council (EPSRC) and Natural Environment Research Council (NERC).

Technology Opportunities and Strategies for Climate-friendly trAnsport (TOSCA)

Intra-EU-27 transport sector-related lifecycle carbon dioxide (CO₂) emissions increased from around 900 million tons in 1990 to nearly 1,200 million tons in 2010, a growth by about 30%. The TOSCA scenarios suggest that these emissions may continue to rise by up to nearly 60% by 2050 in the absence of new policy intervention. If also including half of intercontinental air transportation, the EU-27 transport sector lifecycle CO₂ emissions could more than double by 2050.

TOSCA’s techno-economic assessment suggests that energy use per unit passenger-km or ton-km can be reduced by 30-50% for most transport modes using technologies that could become available during the 2020s, compared to the average new technology in place today; natural fleet turnover would then translate these new vehicle-based reductions into the entire fleet by midcentury. For automobiles and narrowbody aircraft, these efficiency gains can be exploited through reduced driving or flight resistances in combination with a radical propulsion system change. For automobiles (and to some extent light-duty trucks), a promising technology trajectory is the stepwise electrification of the vehicle powertrain: from mechanical, to hybrid-electric, plug-in hybrid-electric, to battery-only and hydrogen fuel cell vehicles. For narrowbody aircraft, open rotor engines optimized for a carbon-fiber airframe with unswept wings, operating at slightly reduced cruise speeds promise the largest reduction in fuel burn, unless travel is shifted to advanced turboprop aircraft. For passenger and freight railways, options in addition to lower driving resistance include increased energy recovery at braking, eco-drving, and improved space utilization, along with other measures. The only exception to these opportunities are state-of-the-art medium- and heavy-duty trucks, which are already comparatively close to the technological fuel efficiency limit and thus offer a lower potential for reducing energy use. In addition, intelligent transportation systems (ITS) could reduce energy use by another 5-20%, depending on the transportation mode. And these reductions in CO₂ emissions can be further complemented by second generation biofuels and electricity from low carbon sources. A more electricity-based transport system also offers ancillary benefits in terms of reduced energy import dependence.

However, exploiting the potential of these opportunities requires policy intervention. Many of the critical automobile, narrowbody aircraft, and (some) ITS technologies and second generation biofuels rely on substantial (EU-wide) R&D investments in order to be produced at large, commercial scale. In addition, a carbon price of around €150 per ton of CO₂ would be required for the proposed narrowbody aircraft technologies to become cost-effective and this price would need to be more than twice for advanced automobile technologies, unless the new technologies are regulated into the market. Moreover, industry would need to be encouraged to make the capital-intensive investments to manufacture these technologies and fuels. Realizing these opportunities thus requires predictable market conditions that need to be ensured by technology and climate policy. Realizing these opportunities also requires society to prioritize climate change mitigation over other needs, as these policy interventions will lead to additional public expenditures (and thus to higher taxes or cuts in other government budgets at times of a public finance crisis) and/or to higher prices and thus decreased mobility.

Importantly, given the continuous growth in transportation demand, even assuming very optimistic adoption levels of promising technologies and fuels, it is unlikely that EC-27 transport sector lifecycle greenhouse gas (GHG) emissions can be reduced to significantly below 2010 levels by 2050, unless affordable and vast amounts of low-carbon biofuels and electricity can be supplied. Hence, it appears that technological measures alone cannot produce large enough reductions in transport GHG emissions to be compatible with EU climate goals, at least by 2050. The question then is better understanding the potential for behavioural measures to mitigate transport sector GHG emissions, which include reducing the need for transport and shifts toward low-emission modes.

Commercial Feasibility of Hybrid-Electric Aircraft

Hybrid-electric aircraft (HEA) rely on a novel propulsion architecture that allows radical changes in aircraft design. As a result, they may offer lower operating costs compared to their conventional jet engine counterparts. This study, funded by the Aerospace Technology Institute, explores the economic case for hybrid-electric aircraft using a unique airline competition model developed for the ACCLAIM project. Based upon a real flight network, each competing airline sequentially maximizes its operating profits, using flight frequency, airfare, and the type of aircraft employed (conventional and hybrid-electric) as a decision variable, until a pseudo-equilibrium is reached. To ensure robustness of the results, the study varies fuel price, seat numbers, and battery characteristics of the HEA.

Our Projects