Environment

Synthetic fuels: climate-neutral mobility thanks to e-fuels?

Leaving the car at home, switching to the bicycle or local public transport, perhaps even trying out car sharing: whoever is interested in environmentally friendly mobility has a number of options from which to choose. Above all, however, it is electromobility, in the opinion of many experts from the fields of industry and politics, which should contribute to slowing down climate change and to mitigating its consequences.

Electric cars promise a new form of climate-friendly mobility provided that they are manufactured and operated with electricity from renewable energies. However, there are still challenges that must be overcome if the battery electric car (BEV) is to prevail.

The charging station infrastructure needs to be further developed and expanded in most countries. Even the production of the batteries still today leaves behind a definite ecological footprint. With their comparatively simple electric motors, the so-called BEVs or battery electric cars require significantly less maintenance overall than conventional cars with internal combustion engines. Consequently, experts expect decreasing work volumes in car workshops and also falling workshop sales if components such as transmissions or exhaust systems are no longer needed and do not have to be maintained.

Climate-neutral fuel

The so-called e-fuels – synthetic fuels produced with electricity from 100% renewable energies - appear to be a possible alternative here. In this process, hydrogen is first of all obtained by means of electrolysis of water - with the help of regenerative electricity. Subsequently, carbon dioxide (CO2) is added to this sustainably produced hydrogen in a chemical process. Such carbon dioxide is taken from the air and/or released as a waste product from industrial processes. Combustion only produces as much CO2 as was taken from the environment during production – in other words we are talking a climate-neutral fuel. These processes are classified as "power-to-liquid" or "power-to-gas", depending on whether they produce liquid (PTL) or gaseous (PTG) fuels. However, even the production of the required starting materials currently still causes environmental pollution.

The advantage: e-fuels could theoretically be used in conventionally powered vehicles and could then make their combustion technology CO2-neutral. They could also be available from the existing network of filling stations for diesel and petrol – so no new infrastructure would have to be built.

E-fuels: a technology with potential – but one with plenty of room for improvement

However, its efficiency is currently only around 13 per cent because of the complex production process. In comparison to the diesel engine (efficiency up to around 45 per cent) and the petrol engine (up to around 30 per cent) – but above all in comparison to the electric engine (90 per cent efficiency), the technology still has significant shortcomings.

And furthermore, e-fuel is still expensive. Experts envisage that in Germany the price would be €4.50 per litre. But the situation was also once quite similar with battery electric vehicles, i.e. with electric cars: in 2013, for example, the price of lithium-ion batteries was still €400 per kWh, six years later it was only about a quarter of that.

Another problem is that in most countries there is a lack of sufficient renewable energy sources and also of capacities to produce e-fuels for a mass market. At least for now. In the medium term, e-fuels in vehicles with conventional drive trains could be on the roads side by side with BEV electric cars and fuel cell vehicles. The blending of e-fuels with fossil fuels is also an option. And in amongst all these possibilities, most experts agree on one point: in the foreseeable future it will not just be the one technology that ensures climate-neutral mobility, but a mix of different ones. And e-fuels could very well be another one of these exciting options.