Electromobility and Renewable Energies: Sector Coupling Connects Two Systems in Transition

The mobility sector currently accounts for around 25 percent of primary energy demand in Germany. Mineral oils account for the largest share. Compared with the electricity and heating sectors, the mobility sector, which is dominated primarily by road transport, is far behind in the use of renewable energies.

Successful electromobility must take into account the dynamic changes in the power supply (photo credit: Fotolia@Simon Kraus).

Electromobility uses electricity very efficiently and is therefore an important building block for achieving Germany's energy and climate goals. By 2020, the German government wants to see one million electric vehicles on German roads. Regenerative alternatives to electric drive are currently having a hard time. The "tank plate debate" has left its mark. Since the use of biomass for energy production competes with the production of food, there is a cap of seven percent on the use of biofuels from cultivated biomass in the fuel mix. By 2030, their share is to drop to 3.8 percent, according to a current proposal by the EU Commission.

Another alternative to fossil fuels is hydrogen vehicles. These use electrolytically generated hydrogen that is converted back into electricity in the vehicle.  The process requires a lot of energy and a lot of provisioning of the renewable electricity. Another alternative is to shift traffic to rail - the most efficient form of electromobility. However, there is currently no progress in sight here.

Energy system in transition

So what is needed to make road transport more climate-friendly in the future? For the reasons mentioned above, electromobility is of considerable importance. The electricity for it comes from the charging station and thus from an electricity system that is currently undergoing a massive transformation. Clear signs of the system transformation are the obvious need for expansion of the power grids, the "roll out" of smart meters currently taking place, and the discussion about time-flexible electricity tariffs.  In recent years, the share of renewable energies in electricity generation has increased significantly. Currently, it amounts to about one third, and the trend is still rising.

Renewable power plants cannot be controlled at will, however, but supply energy depending on the strength of solar radiation and wind speed. Future concepts for successful electromobility must take these dynamic changes in the power supply into account. The mass market for electromobility is encountering an energy system in transition. How can fast charging of vehicles be successfully placed on the market? What business models can be established if the customer brings the necessary flexibility when charging the vehicle? The upcoming changes offer enormous economic and ecological opportunities. Understanding the entire system is a prerequisite for successful long-term solutions. Sector coupling is a core competence.