Biofuels, Synthetics, Gas, and Hydrogen: The Automotive Decarbonisation Drive

Incorporating new raw materials and new energy processes and products confirms the evolution of the refining sector, with renewable fuels as a future value.

Biofuels, synthetic fuels, gas, and hydrogen are some of the alternatives that can achieve decarbonisation in the automotive industry. Each has its unique characteristics.

Advanced biofuels (HVO, biodiesel, bioethanol) are produced from biomass (organic raw materials). Advanced generation uses waste (used cooking oils, animal fats, agricultural residues) through refining or fermentation processes of biomass.

Although they release CO2 when burned (tailpipe emissions), their production absorbs CO2 from the atmosphere, resulting in a net reduction of greenhouse gases (often over 70% in the lifecycle).

Synthetic fuels (e-fuels or electrofuels) are artificially produced from CO2 capture and the addition of green hydrogen. They require large amounts of renewable electricity for the electrolysis process (to obtain H2) and CO2 capture. Their properties are almost identical to conventional petrol and diesel, making them compatible with combustion engines and current infrastructure. When burned, they emit the same amount of carbon dioxide that was previously captured for their production.

Regarding liquefied petroleum gases (LPG or AutoGas), they are a mixture of propane and butane, a by-product of oil and natural gas. It is stored in liquid form at low pressure. Its CO2 emissions are lower than petrol (approximately 15% less), but they are not neutral.

It differs from Compressed Natural Gas (CNG), which is a fossil derivative or biomethane (if it comes from organic waste, in which case it is renewable). Its CO2 emissions are lower than diesel and petrol. Biomethane allows for reductions of up to 100% of CO2 in the lifecycle.

The fifth alternative, Green Hydrogen (H2), is a gas abundantly found in nature. It is used in a fuel cell to generate electricity and power an electric motor.

It is achieved through water electrolysis using exclusively electricity from renewable sources (solar, wind). Its emissions are zero. Other advantages include quick refuelling (similar to petrol) and high autonomy. It is one of the cleanest alternatives, although its infrastructure and cost remain a challenge.