Complex switch to e-fuels | Knowledge

Huge amounts of green electricity are required for the production of “power fuels”.

Drive a climate-friendly car? It would be best if you could just change the fuel, i.e. instead of gasoline and diesel, just fill the tank with e-gasoline and e-diesel. Everything else would remain largely the same, especially the engine. It’s not just car and truck users who dream of a comfortable changeover. Wherever fossil fuels, fuels and raw materials are currently used, there are convenient, climate-neutral alternatives such as hydrogen, methanol, methane, ammonia, e-kerosene or even e-diesel and petrol.

These so-called “power fuels” are produced using green electricity. In the future, this will practically be the new primary energy – instead of coal, gas, oil and, to a large extent, nuclear power. The total energy requirement worldwide is currently over 160,000 terawatt hours. Around 135,000 terawatt hours of green electricity could be enough for a climate-neutral energy system in 2050. This was the result of a study by the Technical University of Lappeenranta (LUT) in Finland, commissioned by the Global Alliance Powerfuels.

The decline in energy demand has a lot to do with the fact that the direct electrification of many processes compared to today’s fossil fuel technologies in itself means a gain in efficiency. In the end, a gasoline engine only brings a third of the energy stored in the fuel to the wheels, while an electric motor takes 90 percent.

Whether a climate-neutral energy system is more efficient also depends on the amount of powerfuels used in the future. Because their production not only requires huge amounts of green electricity to first produce “green” hydrogen. In order to produce easily manageable e-fuels from the green H2 in further steps, carbon is also needed – but not fossil fuels, which generate additional CO2 emissions when burned, which is what caused us climate change.

If the powerfuels are to be climate-neutral, the carbon can only come from the CO2 in the air itself. If the carbon dioxide is withdrawn from the atmosphere and incorporated into the powerfuels, which are then burned and the CO2 released again, mathematically this is a zero-sum game. The researchers put the corresponding carbon requirement for 2050 at around six billion tons of CO2 per year. In the opinion of the study authors, these should largely be obtained with the help of direct air capture (DAC). With this technology, the CO2 is chemically “washed out” or absorbed from the air. “That will be the case in particular from 2040, when the energy system approaches 100 percent renewable energies,” explains Andreas Kuhlmann, head of the German Energy Agency (Dena) and at the same time spokesman for the “Global Alliance Powerfuels”, which also includes corporations and associations of the Oil industry belong.

According to the study, DAC technology is expected to add around 4.8 billion tons to the six billion tons in 2050. The rest is CO2, which is generated in the manufacture of steel and cement as well as in other industrial processes and is “captured” accordingly.

Due to the massive use, the Dena boss expects a greater cost reduction for DAC. In addition, this technology enables powerfuels to be produced in places that have a lot of renewable potential, but where no other sustainable CO2 source is available apart from the ambient air. If there is also global trade in power fuels, their costs could fall to five to eight cents per kilowatt hour by 2050.

This may make climate-neutral fuels affordable – but one problem remains: if the complex production of power fuels consumes too much green electricity, the efficiency of the globally renewable electricity system will decrease and the world’s green electricity potential may not be sufficient to supply everything decarbonize.

The LUT study now outlines a scenario of how green electricity can be used directly and indirectly in such a way that the world is not only decarbonised, but also meets the Paris climate target. According to this, powerfuels should only cover around a quarter of the global energy demand in 2050. The fuels are mainly used where the direct use of electricity “is not economically or technically feasible”, explains Andreas Kuhlmann. This applies in particular to some transport areas such as air and sea traffic as well as high-temperature heating, the production of raw materials in chemistry and to compensate for seasonal fluctuations in renewable energy generation and consumption in some regions.

To make the dimensions clear, which is at stake here: The power fuels alone that are to flow into traffic in 2050 – around 23,000 terawatt hours – embody almost as much energy as all electricity power plants in the world are currently generating. In other words: If today’s global power supply were already one hundred percent green, it would have to flow entirely into the production of climate-neutral fuels so that we can still use aircraft, ships and heavy trucks in 2050.

There are only 30 years left until then. For Kuhlmann, the study shows that it is ecologically and economically necessary to shape the investment environment for powerfuels positively today. “This also means promoting direct air separation of CO2 and the expansion of renewable energies.”

However, if you take the study seriously, it also means: Powerfuels are far too valuable to be burned in private car traffic around the world. Only if their use is limited to the areas where there is really no alternative will we have enough green electricity for a climate-neutral world.

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