Many Roads to CO2-Neutral Mobility

Future mobility must be carbon-neutral. The experts agree on this. But which role will be played by individual powertrain variants and mobility solutions? What has to be done with vehicles, fuels and the infrastructure in order to achieve the emission targets? IAV Mobility Synthesis can be used to derive scenarios and to put planning processes on an objective footing.

Apart from purely technical boundary conditions, future mobility will also have to take into consideration what customers want. “They play a central role and the vehicles have to meet their demands”, says Ralf Tröger from Consulting4Drive, IAV’s management and innovation consultancy. “That’s why IAV Mobility Synthesis also takes account of customer preferences such as the number of acceptable refueling stops or typical journey lengths, in addition to the technical framework conditions.

There are many reciprocal effects and interdependencies between the affected sectors, where the energy industry plays a major role alongside mobility. A fleet operator could be faced with deciding whether to install filling stations for renewable fuels or electricity for his vehicles, as well as looking at the issue of where vehicles with combustion engines will still be allowed to drive in future. An infrastructure operator has to decide whether to install charging stations or refueling stations, in a network that is dense enough to meet customer demands without generating excessive investment costs. Producers of e-fuels in particular need to know which quantities of their products they will be able to sell. And politicians have to decide which measures will have the largest effect in terms of reducing emissions.

Many Roads

IAV Mobility Synthesis considers the interests of all groups and tries to generate a swift, objective comparison of various scenarios. The basic idea involves making certain presumptions about journey distances, driving styles, powertrains and fuels used in order to calculate coefficients such as energy consumption and CO2 emissions.

Customer-specific acceptance coefficient

“In order to view a specific future scenario, we have to take account of all these influences with their trends and repercussions”, says Bernd Becker, head of the Fuels and Future Mobility team at IAV. “The key element is always the customer who selects his preferred mobility concept from the range of available powertrains and fuels or energy carriers. He then decides which form of mobility he wants to use for his specific journeys.” This results in the refueling times, detours and mobility costs for the completed journeys, as well as the impacts on the environment. The respective mobility choice is summarized in a customer-specific acceptance coefficient, which indicates to what extent new technologies and fuels will be able to penetrate the market.

In turn, there are also consequences for CO2 reduction thanks to the significant emission reductions that are possible with renewable energies. Besides battery electric vehicles, this also includes regeneratively produced hydrogen, as well as biofuels and PtX fuels (power-to-X). The energy demand for a certain scenario is calculated from the type of use, customer-specific journey distances, predicted consumption rates and the energy content of the respective energy carriers. “We take account of the efficiency chains in the generation process”, says Tröger. “The renewable energy demand for mobility results from power for recharging batteries, hydrogen and PtX production.”

The ratio of e-fuels to electricity results from the level of customer acceptance: it is easier to travel short urban routes in all-electric mode. On the other hand, fuel cells or PtX fuels will be given preference for long-distance journeys in future. The exact breakdown depends of course on the future boundary conditions, resulting in uncertainty regarding the exact share of vehicles with combustion engine, e-drive and fuel cell.

Future significance of the combustion engine

But future investments in new infrastructure are contingent on this. A larger PtX share means less battery capacity will be needed with lower production emissions (LCA view).

This is a very attractive solution for climate protection because e-fuels will make it possible to achieve carbon neutrality apart from just a few percent. PtX fuels also have the potential of penetrating the vehicle fleet at a faster rate.

Dr. Bernd Becker — Head of the Fuels and Future Mobility team at IAV

Such a scenario would continue to give the combustion engine an important role for future mobility. However, this path has a higher energy demand, although to put it in perspective, PtX fuels can also be easily supplied by imports.

At the moment it is not possible to say for certain which of the numerous possibilities for a future powertrain and mobility mix will prevail in future. But IAV Mobility Synthesis offers an opportunity to compare various scenarios and their impacts on all affected stakeholders, thus providing the basis for decision processes by the OEMs, energy suppliers and politicians.

The article was published in automotion 02/2019, the automotive engineering magazine of IAV. Here you can order the autmotion free of charge.