General information

Decarbonisation of transport for the energy transition

The primary technologies for use in the decarbonization of transportation for the energy transition focus on electrification, the development of carbon-neutral liquid fuels, the development of green hydrogen fuel cells, and the use of liquefied natural gas (LNG) to replace other fossil fuels.

The transition towards decarbonised mobility requires specific measures for each type of transport. The most efficient technological solutions may be different for road transport – both heavy and light, maritime, rail, and air transport. 

In general terms, the main transport decarbonisation technologies focus on electrification, the development of carbon neutral liquid fuels (biofuels produced from agricultural, forestry, urban, and plastic waste and synthetic fuels or e-fuels made from captured CO2 and hydrogen), the development of fuel cells with green hydrogen, or the replacement of other more polluting fossil fuels with liquefied natural gas (LNG), especially in the specific case of maritime transport.

Both in Spain and in the rest of Europe, emissions from road transport – passenger cars, mopeds, light vehicles, heavy vehicles, and buses – represent more than 70% of greenhouse gas (GHG) emissions related to mobility. 

This significant contribution of emissions, coupled with a growth in the number of private vehicles since 1990 and the deterioration of air quality in urban centres, places road transport as a vector for the transformation of mobility, especially in large urban centres, incorporating important regulatory changes that foster the use of new, more efficient forms of transport with fewer emissions.  The increase in the use of new technologies such as electric cars, hybrid cars, and alternative fuels – liquefied petroleum gases (LPG), compressed natural gas (CNG), biofuels, and synthetic fuels – is proof of this.

Decarbonisation versus electrification

In combustion vehicles, it is because of the burning of fuel. In electric vehicles (EV) or plug-in hybrid vehicles, CO2 emissions will depend on how the electricity from which the battery is charged (the electricity mix) is generated.

In the specific case of Spain, in comparison with conventional internal combustion vehicles, electric vehicles reduce its carbon footprint by 48%, and could reach 58% by 2030 and 62% by 2050 if its implementation is accompanied by a growth in renewable electricity generation1. This is due to the electricity mix in Spain including a large contribution of renewable energy, but it isn’t the same for all countries. 

As well as the electrification of the vehicle fleet, low carbon fuels (which include advanced biofuels and synthetic fuels, or e-fuels) are a sustainable and feasible alternative for decarbonisation of the sector, which could be implemented immediately. 

New low carbon fuels

Advanced biofuels are those that are produced from biomass that isn't in competition with the food sector, such as agro-industrial, forestry, or municipal waste. By having similar properties to the fuels that we know, they are compatible with current combustion vehicles. 

Low carbon fuels are a feasible option that allows us to make the most of the existing distribution and refuelling network without needing to develop charging infrastructures or renew the vehicle fleet.

Synthetic fuels, or e-fuels, are those that are produced from the combination of captured CO2, either from a concentrated source or directly from the air (DAC), and renewable hydrogen. Synthetic fuels can achieve net zero emissions depending on several factors such as the origin of the hydrogen and the energy used in the production process, as the total CO2 emitted is the same CO2 captured for their production. They are also compatible with the current infrastructure and vehicle fleet.

Renewable hydrogen as an energy vector for mobility

Requirements for the development of advanced biofuels

So that biofuels constitute a renewable alternative to fossil fuels, a transformation of the refining industry is necessary, with the aim of all processes and products having net zero emissions. Thus, the circular economy would reinforce its key role in the energy transition.

Existing facilities can also be used for their production and distribution by transforming some of the current processes with solutions based on the circular economy. Currently, European refineries are being transformed into energy hubs, capable of treating all types of organic waste and converting it into fuels with low carbon footprints.


1 Puig-Samper Naranjo, G., Bolonio, D., Ortega, M. F., & García-Martínez, M. J. (2021). Comparative life cycle assessment of conventional, electric and hybrid passenger vehicles in Spain. Journal of Cleaner Production, 291.


Sustainable mobility, Challenges posed by climate change and energy transition Hydrogen Decarbonization
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