Powertrains and Energy Systems of Tomorrow 2024

Author: Marc Ziegler

News from the MTZ Congress Powertrains and Energy Systems of Tomorrow 2024

How Can the Mobility Turnaround Succeed?

High costs, bans and technology openness: The switch to climate-friendly mobility is a key topic at the MTZ congress "Powertrains and Energy Systems of Tomorrow 2024".

After the introductory words by Professor Dr. Peter Gutzmer, Scientific Director of the event, Ines Fröhlich, State Secretary of the Saxon State Ministry of Economic Affairs, Labor and Transport, opened the congress with her keynote speech "Mobility transition in 2024 – how the challenges are constantly changing". There is no question about people's need for mobility, but according to her, a mobility turnaround can only be achieved together with customers and not against them. The OEMs based in Saxony currently produce 250,000 electrically powered vehicles per year with a forecast of 320,000 units in 2024. 

The conscious switch to climate-friendly mobility requires electric vehicles to become affordable for a broader group of buyers. Almost 80 % of passenger transport is currently accounted for by private transport, so enormous savings could be made here, for example by switching to alternative transport concepts. According to Fröhlich, this includes many sharing offers and local public transport as well as the conversion of truck traffic from road to rail. She sees a further opportunity in the development of a functioning hydrogen infrastructure. According to her, those who are prepared to adapt and move in order to find joint solutions for a new mobility structure will be successful in the long term. In this context, Fröhlich is critical of the ban on the combustion engine, saying that gradual change makes perfect sense, but unilateral bans do not.

Hydrogen Infrastructure Technically Feasible

Professor Dr. Thomas von Unwerth from Chemnitz University of Technology made a fiery plea for hydrogen as the energy source of the future in his presentation "Hydrogen as a sustainable energy carrier – potentials for the energy and mobility transition". He began by emphasizing how great the global demand for energy actually is. Road traffic as a whole is responsible for almost a quarter of CO₂ emissions. According to him, the drivers of the energy transition are society, the energy sector, competition and legislators. CO₂ emissions have been significantly reduced over the years, requiring huge investments in new technologies and platforms (target 95 g CO₂/km). At present, all energy paths are ultimately CO₂-intensive. According to Unwerth, the only way to achieve actual CO₂ neutrality would be the direct use of immediately usable green electrical energy. 

However, as this is not a given, Unwerth considers hydrogen to be the only other alternative that can be stored and transported. By 2030, the plans envisage a Europe-wide production capacity of 27 million tons compared to a total demand of up to 68 million tons (100,000 tons in transport). Both the distribution of H₂ in the existing network and storage in natural structures (caverns) are possible. Unwerth presented various paths for the use of hydrogen in mobility. The efficiency chain of direct use of electricity always has the highest efficiency (around 61 %). The efficiency of synthetic fuels is the lowest (25 %) and the use of hydrogen is somewhere in between. Under cold conditions, this ratio shifts in favor of hydrogen. If the availability of renewable electricity is taken into account, the drive types converge further depending on the region.

E-Cars as Energy Storage

Dr. Urban Keussen from EWE AG spoke about the possibilities of energy storage in his presentation "Electric cars as a storage device for the energy system – a game changer or no change at all?". Molecular storage systems, i.e. in gas or liquids, are much more important than current battery storage systems. With the capacities available, storage in the form of molecules can provide energy security for months, whereas with batteries it is currently more a matter of hours. In the future, there will nevertheless have to be a variety of solutions in the energy system. To stabilize the grid, grid scale batteries, i.e. large batteries, are being discussed, which are used directly as storage capacity in the grid to actively trade energy. On a smaller scale, there are batteries for electric vehicles, which can be used as storage for individual households. Integrating electric vehicles into the energy system of homes could significantly increase the use of self-produced energy through photovoltaics. In addition, variable electricity prices offer the opportunity to charge at particularly favorable times. Unfortunately, this may lead to grid overload, which in turn can lead to higher grid charges. In order for vehicle batteries to have a relevant stabilizing effect in the system, external control is also necessary, which is currently still difficult to implement. However, Keussen believes that bidirectional charging will be relevant in the future. 

Affordable Electromobility Difficult to Implement

Lars Hentschel, Head of EAE at Volkswagen AG, concluded the keynote session with his presentation "Impact of the energy infrastructure and mobility ecosystems on future high-voltage architectures". Hentschel explained various energy ecosystems and the influencing factors at work here. In relation to the overall energy system, the vehicle is only a single item and as such the system is not geared towards its needs. In fact, over 90 % of daily journeys are made within a radius of less than 100 km. The 1,000 km range, an important parameter for customers according to Hentschel, is not achieved with BEVs, which is why hybrid drives are still in high demand. 

The e-hybrid combines a 1.5-liter petrol engine with a high-voltage battery and an electric motor, with a purely electric range of around 100 km and a total range of 1,000 km. The vehicle can be charged at 11 kW using alternating current and 40 kW using direct current, meaning that a SOC charge of 10-80 % takes 26 minutes. Hentschel also sees a strong trend towards V2X applications. The vehicle is used as an energy supplier in leisure time, for example for charging or using external electrical devices, as storage for the home (V2H), to stabilize the grid or even to charge other vehicles. Wherever possible, the customer of a BEV should not be involved in negative experiences when using it. According to Hentschel, there is great potential for efficiency in classic mechanical engineering, namely in the transmission, but also in the electric machine and in the power electronics. This can also be seen in the comparison of current products with their predecessors, which have become up to 10 % more efficient despite higher performance. Looking ahead, the customer demand for ever greater dynamics will initially be met, but the costs for BEVs will not fall significantly until 2025/26 due to a new architecture with front-wheel drive and lower performance, with Hentschel emphasizing that affordable e-mobility is one of the biggest challenges.

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