Scenarios for carbon-neutral transport: Which actions achieve the goal?

The transport sector’s contribution to achieving the climate targets is still unsatisfactory. In contrast to other sectors such as energy and buildings, CO2 emissions have hardly fallen since 1990, the baseline year, and have even been rising in recent years. There are enormous challenges if the greenhouse gas emissions generated by transport are indeed to fall by 40–42 per cent of 1990 levels by 2030, in line with the German government’s Climate Action Plan. By 2050 the transport sector must be carbon-neutral.

The magnitude of the task demands a strategic approach. With the aid of scenarios, it is possible to demonstrate which measures and instruments can produce real contributions to climate change mitigation and what the impact is of combining different instruments.

Scenarios demonstrate possible trajectories

A number of Oeko-Institut research projects have developed scenarios demonstrating strategies for climate policy, each of which uses a variety of approaches (for example, more efficient vehicles, modal shift, new types of fuel) or combinations of these strategies to achieve the target.

Various development paths are analysed in detail: is enough electricity from renewable sources available for converting whole vehicle fleets to electric drives? What are the most promising options for freight transport? Factors such as the national economy, quality of life in the cities and the ease of implementing measures are also relevant here.

Hitting the target: A combination of different measures to curb climate change

The need for action in the transport sector is so great that a combination of measures is analysed in all scenarios. For example, if the policy framework is based purely on the use of more efficient vehicles and e-mobility, emissions fall by a maximum of 30 million tonnes by 2030. This is not enough to reach the climate targets; a reduction of another 20 to 30 million tonnes must be achieved by means of other instruments.

Essentially, an ambitious climate policy in the transport sector provides opportunities, not only from the environmental aspect, but also for the economy and society as a whole. This is shown by a wealth of studies and research projects in which the Oeko-Institut is involved.

Study: Climate change mitigation in transport – action to achieve the sector’s target

What is needed to reduce emissions in the transport sector to a sustainable level and to reach the climate targets is a mix of ambitious measures. In a study commissioned by Agora Verkehrswende, the Oeko-Institut and the International Council on Clean Transportation (ICCT) looked at which transport policy instruments are available, how many tonnes of greenhouse gases each of these saves and what possible combinations are realistic.

The “climate gap” between the reduction targets to 2030, to which the German government is committed, and the projected greenhouse gas emissions amounts to at least 48 million tonnes of CO2 equivalent, if no further action is taken.

Analysis of the climate impacts of twelve instruments

The researchers investigated various levels of ambition for each type of instrument. For example, a motorway toll of two cents per kilometre for cars results in a reduction of 1.8 million tonnes of CO2 by 2030. If the toll is raised to four cents and extended to all roads, there is a reduction of 12.8 million tonnes.

Bringing the tax on diesel into line with that on petrol saves 3.7 million tonnes of greenhouse gases, and a simultaneous rise of 15 cents a litre cuts emissions by 9.2 million tonnes. A reduction in traffic by encouraging public transport use, cycling and walking brings significant extra health benefits for people – in addition to having a positive impact on the climate.

Three scenarios: More efficient vehicles, traffic reduction, carbon-neutral fuels

The study presents three scenarios, each with a different combination of instruments, and examines their potential implementation. The outcomes suggest that neither the electrification of transport together with substantially more efficient vehicles, nor a modal shift and a reduction in traffic volumes, nor indeed the use of synthetic fuels can achieve the target alone. What is required instead is a skilful combination of the individual building blocks.

“Klimaschutz im Verkehr: Maßnahmen zur Erreichung des Sektorziels 2030”: study by the Oeko-Institut and the ICCT on behalf of Agora Verkehrswende

Project: Renewbility III – options for decarbonising the transport sector

The Renewbility research project creates scenarios for the total decarbonisation of the transport sector by 2050. “Total” means that exclusively electricity or electricity-based fuels from renewable energy are used in passenger and freight transport. The study, commissioned by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB), also includes aviation and shipping.

In addition to the benefit for the climate, the researchers looked at the macro-economic effects of each scenario. In this respect electromobility, the moderate use of carbon-neutral fuels, particularly for aviation and shipping, attractive local public transport and the upgrading of rail transport have clear positive impacts on the national economy in the long term.

Using the Renewbility outcomes tool to analyse scenarios for mitigating climate change in the transport sector (website in German language) - Click image to open the tool.

A carbon-neutral transport sector is possible: There are various options

All the scenarios examined as part of Renewbility III result in a transport sector with zero greenhouse gas emissions by 2050. There are various ways to achieve this. The cornerstone is e-mobility, as direct use of renewable electricity is preferable to using electricity-based fuels whenever possible.

A better quality of life in car-free cities

Changed settings in cities can bring about a significant reduction of around 50 per cent in the number of individual motorised vehicles. Attractive offers of public transport as well as for cyclists and pedestrians, combined with restrictive measures for cars such as raising parking charges, lead to a modal shift. A positive side-effect is an improvement in quality of life.

From an economic perspective, some sectors are hit harder than others. Growth in electricity generation, the service and construction industries and public transport is to be anticipated, while sectors including petroleum, car manufacturing and air travel must expect to lose out. The net effect, however, is positive and presents new opportunities.

The follow-up study Renewbility IV is being carried out at present and by the end of 2019 will be focussing even more closely on instruments to cut greenhouse gas emissions from transport. The research team is also advising the German environment ministry (BMU) on the development of transport targets for the 2050 Climate Action Plan and on the CO2 limits for passenger and heavy commercial vehicles in the EU process.

Brochure: “Renewbility III – Optionen einer Dekarbonisierung des Verkehrssektors” led by the Oeko-Institut, in collaboration with DLR Transport Research, the Institute for Energy and Environmental Research (ifeu), Heidelberg, and Infras, Zurich

Final report: “Renewbility III – Optionen einer Dekarbonisierung des Verkehrssektors” led by the Oeko-Institut, in collaboration with DLR Transport Research, the Institute for Energy and Environmental Research (ifeu), Heidelberg, and Infras, Zurich