Energy for Mobility
The German energy transition is pursuing the goal of converting the energy supply in all sectors to sustainable sources by 2045. As a result, the transport sector faces a particular challenge, because it is currently based to almost 95 % on fossil energy from oil and natural gas. The reason for this is that there have been few similarly economical alternatives to conventional fuels because of their high energy density, ease of use and low cost.
What now?
A clever combination of different solution strategies is crucial to achieving the climate targets. We want to create a solid scientific basis for evaluating these strategies and research them transparently and with an open approach to technology. One yardstick can be a life cycle assessment of a drive system, which considers the production, use and disposal of its components (life cycle assessment).
Electrification
Solar energy and wind offer a low carbon footprint with low manufacturing costs and good availability. Photovoltaics and wind power already account for around 50 % of the German electricity sector. To enable greater coupling with the transport sector, the most energy-efficient solution is to increase the expansion of electromobility. Green electricity thus flows directly into mobility, requiring high investments in infrastructure and vehicle fleet, however. Electricity supply and demand also need to be better matched via intelligent control of grids and electricity consumers to become less dependent on fossil fuel baseload suppliers.
Hydrogen
The main disadvantage of solar and wind energy is that electrical power must always be generated and consumed simultaneously. The creation of energy storage facilities is therefore crucial in order to secure demand regardless of weather conditions and to provide for crisis situations. The main aim here is to generate hydrogen through the electrolysis of water. Although the flexibility achieved in this way must be paid for with an energy loss of around 30 %, hydrogen can also serve as an energy carrier for transport and thus reduce the need for battery storage. Suitable vehicles are either electrified cars, which have a small battery only and also draw their power from a hydrogen fuel cell. Or hydrogen is used as a fuel in internal combustion engines, producing no CO2 emissions either.
E-Fuels
In order to equip vehicles with hydrogen propulsion, complex pressurized tanks or low-temperature storage systems must be used. It therefore makes sense to convert hydrogen into more easily manageable energy carriers. Methane, methanol, ammonia, dimethyl ether or even synthetic gasoline / diesel / kerosene can be produced using established processes. With the exception of ammonia, carbon is required for this process, so additional effort must be made to capture CO2 from ambient air. However, such fuels are still neutral in terms of CO2 and can be traded easily worldwide via pipelines or ships. This makes large amounts of solar and wind power accessible, which in other countries can be generated at much lower costs than in Germany and thus compensate for the energy losses that occur.