The future of transportation will consist of battery-powered electric vehicles and the use of sustainably sourced fuels such as biofuels, and the latter will require a range of relief valves and other safety systems to ensure it is produced, stored and transported safely.
Whilst biofuels are the most commonly known, they are not the only ones to be widely used, with electrofuels or eFuels being increasingly common in a wide range of sectors.
It can be somewhat confusing, particularly since many sectors such as motorsport have opted to use various blends of both biofuels and eFuels, and both types of drop-in alternatives to petrol and diesel have various advantages and mitigating factors in place.
What Are Biofuels And Electrofuels?
It is important to define both electrofuels and biofuels, as there is some overlap between the two.
A biofuel is any fuel source that is produced from biological matter or biomass, typically consisting of plants, agricultural byproducts, algae material, animal silage and some forms of food waste.
By contrast, electrofuels or eFuels are synthetic hydrocarbon fuels produced by mixing carbon dioxide from carbon capture sources and water from electrolysis, creating a fuel that is chemically identical to fossil fuels.
Where Are They Used?
They are both used as alternative fuels that reduce the reliance and environmental cost of using fossil fuels, but how this is applied varies considerably, which has increasingly led to cases where both eFuels and biofuels are used in the same vehicle.
Biofuels tend to be blended with either petrol or diesel in various blends, from 100 per cent bioethanol as has sometimes been the case with Brazilian flex-fuel cars, to relatively modest E10 petrol, a ten per cent bioethanol blend compatible with most modern cars.
By contrast, eFuels are typically used as drop-in replacements, particularly for industries where a transition to a substantially different fuel source, such as a hydrogen fuel cell or a significantly different form of biofuel, may not necessarily be economically viable in the short term.
What Makes Them Green And Sustainable?
Both biofuels and eFuels are renewable by the broad definition that both fuel types are derived from materials that are plentiful or easily replenished. Biomass grows quickly, whilst carbon dioxide and hydrogen are amongst the most abundant molecules on Earth.
However, the method of production also matters in both cases, and the green credentials of both are defined by very different mitigating factors, particularly since burning either of them still leads to carbon emissions.
Biofuels tend to be carbon neutral due to the carbon absorbed by the biomass material as part of processes such as photosynthesis during the growing phase of the biological material, but there may be a carbon cost to its harvesting, the energy used in refinement and finally in its use in engines.
There are also concerns regarding the need to use high-quality farmland to produce crops that are not a source of food but instead are used to produce fuel, potentially creating food shortages through perverse incentives.
By contrast, eFuels can be as green as their sources of carbon dioxide, hydrogen and energy for electrolysis, particularly since the water splitting process is somewhat energy-intensive.
Carbon Dioxide can be acquired through carbon capture, but it can also be obtained through less sustainable means, such as carbon capture and utility, which can undermine the process.
Similarly, there are a lot of different ways to acquire hydrogen gas, but for an eFuel to be considered green, it must be produced through the use of green hydrogen, which is hydrogen produced through electricity rather than the processing of fossil fuels.
Finally, the source of electricity matters as well; electrolysis is a green process as long as the electricity used in the process is also supplied through renewable means, such as solar, tidal, hydroelectric and so on.
What Are The Differences In Cost?
The biggest difference between the two types of fuel, and one that will likely take a long time to balance out, is the price of the different types of fuel.
Whilst drop-in eFuels are ideal for a lot of transportation purposes, the biggest barrier to their adoption has been price; they are significantly more expensive than either fossil fuels or biofuels.
This is primarily due to the cost of producing green hydrogen, which has also caused issues for hydrogen fuel cells as a potential alternative fuel and the adoption of hydrogen as an alternative for natural gas in boilers.
Biofuels cost less by volume, but not every vehicle at present can use biofuels without extensive modification.
