As we continue to explore more sustainable alternatives for fuel, we thought this week we would explore synthetic fuels and the progress the energy industry is going to make progressive, bold choices.
So, will synthetic fuels be the next revolution? The concept of a carbon-neutral engine could become the next big change we see in the transportation industry. Globally we are working to lower our carbon emissions, and a staggering ‘2.8 gigatons of CO2 could be saved by 2050’ with the introduction of synthetic fuels. These fuels are considered to play an important role to reach net zero targets within the transportation sector.
You may be wondering what are synthetic fuels? To put it simply they are fuels that have the same properties as fossil fuels but are produced artificially and can be used in the same way fossil fuels are used. With the potential to produce it for the use of jet fuel, diesel, gasoline for planes, ships, trucks, and cars. The main difference comes down to the production, we know fossil fuels are formed from millions of years of organic material that became coal, natural gas, or oil. Synthetic fuels are produced by mimicking these processes, using renewable resources.
How are Synthetic Fuels Produced?
To be able to understand how synthetic fuels are produced, we first need to know how natural fuels are formed and what the main components are. These fuels are made from carbon and hydrogen elements, hundreds, and hundreds of chains of hydrocarbon molecules.
To manufacture synthetic fuels, you need a mixture of hydrogen and carbon monoxide. Synhelion a company that produces solar fuels explains it as ‘syngas’ a synthetic gas if you ‘think of syngas as a brick. Once you have bricks, you can build any shape of house. Syngas is the universal brick you need to produce any type of liquid hydrocarbon fuel, such as jet fuel, diesel, or gasoline.’ This presents the opportunity to provide a variety of different types of fuels, for different methods of transport. Currently the production of syngas relies on non-renewable materials, coal and gas and it requires a large amount of energy. So, the challenge is producing it in a sustainable method, with alternatives such as wind, solar, hydro and biomass.
Types of renewable synthetic fuels
We know that overall, the production of synthetic fuels is not entirely sustainable. However, there are currently three methods of production that are, biofuels, e-fuels, and solar fuels. Biofuels are produced from biomass, e-fuels with renewable electricity and solar fuels use heat. All methods go through syngas, a mixture of hydrogen and carbon monoxide and are turned into liquid fuels via industrial gas-to-liquid processes.
Biomass to liquid produces biofuels:
There are several processes to convert biomass into liquid fuels, currently the most scalable and versatile in terms of feedstock is via gasification of biomass. The biomass is converted at high temperatures into syngas. Feedstocks can be ad hoc plants, including energy crops such as sugar cane or corn, waste biomass or algae. Currently they are the only renewable synthetic fuel on the market but have received criticism for using arable land that can be used within the food industry, as well as water consumption and limited scalability.
Power to liquid produces e-fuels:
E-fuels are produced with renewable electricity such as solar, wind or hydro power. The electricity is generated, driving an electrolyser that splits water into hydrogen and oxygen. The hydrogen is mixed with carbon dioxide and turned into syngas via a reverse water gas shift, a process that requires high temperatures. E-fuels are currently not on the market as no industrial fuel plants exist. The delay for brining this to market is the reliance on electricity storage, limiting the application to regions with cheap and continuous renewable electricity supply and requires the integration of expensive battery technology.
Sun-to-Liquid produces solar fuels:
As the name suggests, solar fuels are produced from solar heat, that drive a thermochemical reactor. In the reactor carbon dioxide and water are converted into a syngas. Like E-fuels, Solar fuels are currently not on the market. Installation in sunny regions, like deserts offer the ideal location for production, solar can be stored by thermal energy storage for round the clock production of solar fuels.
How can synthetic fuels be used?
We’ve learnt how to produce synthetic fuels, so how can we introduce them with existing infrastructure? Well luckily, they are compatible and can be used with many transportation vehicles. The challenges we face are being able to produce the volume of these fuels to meet current demands and for the carbon emissions to be significantly lower than the methods we currently undertake. So, the benefit of these processes outweighs the methods we use now. It will be interesting to see how this technology is developed and with more investment we can hopefully rely on renewable synthetic fuels, to slowly replace fossil fuels in the future.
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