E-fuels to drive decarbonization

Water and CO₂ to fill your tank: This fuel helps to decarbonize mobility

Synthetic fuels, also called e-fuels, are carbon neutral and can be used in current car, truck, plane, and boat engines.

Can you imagine if the fuel that powers your vehicle was made from water? And that CO₂ captured from the atmosphere was also used for producing it? It may seem like an unlikely scenario or of science fiction, but synthetic fuels, also called e-fuels, are a totally real alternative.

But, how can a fuel be developed using water and CO₂? The process is as follows: The first step is to separate the oxygen and hydrogen particles from water by applying renewable electricity, normally wind or photovoltaic, in a process that's known as electrolysis. The result of this process will be renewable hydrogen.

The second step is to capture CO₂. To do this, devices are used to collect air directly from the atmosphere and extract the CO₂, which can be processed and reused. And that is precisely what is done in the third and final step: combining the renewable hydrogen and the CO₂ to generate the e-fuel at an industrial plant.

How can these fuels change mobility? First of all, they're carbon neutral, so they're going to contribute to decarbonizing the sector. As explained by Javier Aríztegui, a Repsol Technology Lab portfolio manager, “The CO₂ released during its usage is offset by the amount previously captured to manufacture it. In this way, we create a reuse loop and no additional CO₂ is added to the atmosphere.”

On the other hand, e-fuels are compatible with combustion engines, so they can be used in existing cars, planes, boats, and trucks, as they offer similar performance compared to conventional fuels given that their chemical composition is very alike.

Furthermore, "the energy density of these fuels is higher compared to other alternatives such as hydrogen," assures Pelayo García de Arquer, a group leader at the Institute of Photonic Sciences (ICFO) and expert in the use of CO₂ and renewable hydrogen as fuels. In other words, e-fuels are capable of concentrating a high amount of energy in a small space. This represents an advantage when it comes the long distances covered by large means of transportation. Also, "when a certain range is required and many kilometers have to be traveled daily, the entry of hydrogen in its different forms has a much more important role," Aríztegui adds.

"By combining all the solutions we have on the table, we'll be able to ensure that mobility does not emit new greenhouse gases," claims Javier Aríztegui.

Likewise, García de Arquer reminds us that the use of these fuels "is compatible with current production chains in the petrochemical industry," as processes such as the distribution or storage of fuels, for example, are identical for conventional and synthetic fuels. All of that "brings with it a greater ease of use for consumers and a lower barrier to market entry."

In fact, the Spanish Association of Petroleum Products Operators (AOP) itself points it out as an element of innovation within industry, alongside advanced biofuels. For this association, making use of this new generation of fuels will be fundamental in the coming decades to decarbonize mobility: “The transportation of people and goods will continue to need liquid fuels as a main energy source for a long time. The current access costs to technology or the limitations of existing technological developments make alternatives necessary with increasingly less emissions, efficient, and accessible to all."

Innovation to develop sustainable alternatives

The production of these new fuels is seen as a turning point for Spanish industry. Repsol is an example of this as it plans to build in Bilbao one of the largest synthetic fuel production plants in the world, which will be operational by 2024. These fuels will be able to be used in combustion engines such as those currently installed in cars, planes, trucks, and boats.

The Spanish company isn't the only company that's carrying out developments surrounding e-fuels. The airline KLM, for example, operated its first flight with this type of fuel produced using CO₂, water, and renewable energy at the start of 2021. Boeing, for its part, is also committed to synthetic fuels. It's no coincidence that these two examples come from the aviation industry: European companies have committed to their flights being net zero emissions by 2050, while increasing the use of Sustainable Aviation Fuels (SAF). According to its proposal, SAFs could reduce emissions in this industrial segment by 34%.

According to Javier Aríztegui, the commitment to e-fuels in the end can't be considered a trend but a reality that will continue to grow as time goes by. “In the future, what we'll see is that new forms of energy are being incorporated, but that doesn't mean that the existing ones will disappear, but rather that we'll reach a point of coexistence in which we'll see different technologies that have been introduced at different times,” such as electric charging, advanced biofuels, renewable hydrogen, and synthetic fuels. All of that, in his opinion, “responds to a logic of decarbonization of mobility, which is the ultimate objective. By combining all the solutions we have on the table, we'll be able to ensure that mobility does not emit new greenhouse gases."

_{Published in El Confidencial}