E-fuel: Overrated or Indispensable?

How climate-neutral is e-fuel really?

Possoch: Let’s look at the climate-neutral buzzwords: Is e-fuel really climate-neutral?

Ueckerdt: This is possible. Important projects also aim in this direction, that is, they use 100 percent renewable electricity, for example in Chile at the Haru Oni ​​plant and they really want to extract carbon dioxide from the atmosphere. This is the “best case”.

But I want to say something else about this climate impact: It is important that e-fuel is, in principle, the inefficient use of renewable electricity. It’s okay if you can’t get over it. But of course it has implications. Not only on costs, but also on the entire life cycle carbon footprint. Because all the carbon dioxide that is in electricity is twice as efficient and then five to six times that in fuel.

On the one hand, this means that if we mix more fossil-based electricity, the climate balance will tip over and there will be no climate protection effect. But on the other hand, even if we mobilize 100 percent solar and wind, they also have a carbon dioxide footprint and it’s not very small.

It’s the best we can do, but that footprint is also multiplied, so that there’s still an emissions base in e-fuels – at least as long as we don’t use the industrial processes needed to manufacture the systems, it also has to be completely carbon-neutral.

Possoch: Transportation from Chile or somewhere else to Germany, for example, also has to be climate neutral for the calculation to work, right?

a cook: If you have transportation of fossil crude oil from the corresponding sources of crude oil on Earth, we transport that to Europe and the transportation there is very energy efficient, even though it is based on fossil energy, no question. But ships are highly efficient and transport them very efficiently across the world’s oceans at low speeds and in large quantities.

But transportation losses are introduced, you’re right. It must be taken into account. Yet they do have such a benefit because the harvest factor for photovoltaics and wind turbines is much better in favored locations than here in the Black Forest or Hamburg, because the sun doesn’t always shine here and the wind doesn’t always blow.

The main criticism of synthetic fuels: efficiency

Possoch: One of the biggest criticisms of e-fuel is efficiency. There are different calculations, for example from the “VDE Association for Electrical, Electronic & Information Technologies”: electricity from a 3 megawatt wind turbine is enough for 1,600 electric cars, 600 hydrogen cars or even 250 e-fuel cars. Is efficiency really that bad?

a cook: You also have to take everything into consideration with the electric car: you have wild losses to the power grid. You have low voltage power grid losses. You have the storage losses in the car via the wall box, via the power electronics in the battery, where massive cooling is required and the energy is ultimately dissipated as heat.

And then of course there are losses in the battery, in the power electronics, in the electric motor, in the transmission during operation. You have downtime losses and of course you also have heating losses. They must also warm the vehicles.

If you take all this into account, you certainly no longer have an advantage in electric mobility on average. There are individual areas of application where electric mobility is great. This is not a plea against technology, but a plea to use it where the strengths of the technology are particularly good.

Ueckerdt: Electricity’s efficiency of kinetic energy on the road is poor and still is poor. There is little room for improvement, but there are also physical limitations.

You’re trying something crazy here: you’re trying to stick to one hydrocarbon and stick to combustion. This has drawbacks. The combustion process in the car alone loses about 70 percent of the energy, so it’s just from the tank to the road. This is inherent in the combustion process. With the battery to the electric motor, you lose 10 to 20 percent, much less.

You also lose about 50 percent of the energy in fuel production because it’s actually a cumbersome process. However they are attractive because the product you end up with is very similar to fossil fuels and you can continue to use the fossil infrastructure.

But back to efficiencies: one could argue that perhaps electricity is cheaper elsewhere or that the wind blows more often and for longer. The full load hours for wind turbines in Chile, for example, are higher. This is correct. At the same time, you really have to look at the costs in the end. Investments there in southern Chile, in Patagonia, for such wind turbines pay high risk premiums. This will change. But it makes sense in principle to start with electricity and then perhaps compare the costs of generating electricity. There is another small factor that comes in, but it will never be able to compensate for these losses in efficiency.