What Is Synthetic Fuel?

June 22nd, 2023

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You’ve probably heard that the way that the oil and gas fields that produce the petrol and diesel we put in our internal combustion engine (ICE) cars were once ancient forests that were somehow buried and transformed into the form they are in today.  You may have wondered whether it would be able to make something chemically identical to crude oil or refined oil in the lab, given that we know the chemical formula for petrol and diesel.

Well, you aren’t alone in wondering whether that could be possible. The truth is that it is possible to make petrol and diesel artificially in the lab without taking the aeons of time involved in fossil fuels.  The result is called synthetic fuel or synfuel.

Synthetic fuel differs from biofuels such as ethanol because it is designed to be completely chemically identical to ordinary bog-standard fossil fuel petrol.  This means that it can be used as is in a car with an unmodified internal combustion engine without being blended, which is what happens with biofuels (you know – E10 is 10% ethanol and 90% fossil fuel petrol).

Synthetic fuel is nothing new. In fact, the idea of making petrol for cars (and planes) from something else was tried successfully back in 1930s Germany, except that they used coal as their starting feedstock.  This was one reason why the German army was such a threat during World War 2: they could manufacture their own synfuel out of coal, which they had, rather than relying on oil wells overseas and the associated supply chain.  However, this method is unlikely to be used these days, as coal is still a type of fossil fuel and wouldn’t suit the purposes.  

The process of making synthetic fuel or synfuel starts with the very common gas hydrogen. The hydrogen is then combined with carbon (carbon monoxide) to make syngas (chemically identical to natural gas but made artificially). This is where the exciting part of synfuel comes in, as the process can either take the carbon from some source or it can even capture the carbon out of the atmosphere. This means that when the synfuel is used in an internal combustion engine, the carbon is just going back into the atmosphere where it originally came from rather than adding new carbon. (OK, you could argue, like one of my relatives does, that what’s in fossil fuels was originally in the atmosphere when that ancient forest was green and growing, but that’s another topic and another debate altogether that I won’t get into here.) Anyway, syngas is made up of hydrogen and carbon molecules (it’s a hydrocarbon, as opposed to a carbohydrate) and can be messed about with to make different types of fuel, including petrol.

The three main ways of producing synfuel are biomass to liquid, power (or electricity) to liquid and sun to liquid.

The biomass to liquid process uses organic matter as a feedstock, which provides the hydrogen and the carbon. This organic matter doesn’t have to be an oil-producing crop, which is what happens with some types of biofuel.  Instead, agricultural waste matter can be used as a feedstock, as can domestic waste. In fact, if the idea of synfuel catches on and becomes more widespread, they’ll be able to use what’s in the landfills and what we chuck out. This avoids the problem of deciding whether good crop-producing agricultural land should go to producing an oil crop to power internal combustion engines or to producing food. This type of synfuel can be referred to as biofuel, although “biofuel” is a confusing term that covers ethanol as well as biodiesel, so it’s best avoided.

Power to liquid production produces the type of syngas known as e-fuel. In this process, electricity (which can be generated by renewable means, such as wind or solar) splits a water molecule to get hydrogen and oxygen, and the hydrogen is then combined with carbon from the atmosphere. The main byproduct is oxygen, and if the process can use renewable sources of energy, then it’s as close to carbon neutral as petrol can be.

Sun to liquid production is less common. In this process, a reactor catches the heat energy of the sun (not photovoltaic energy or solar power) and uses that energy to convert water and CO2 into syngas.

I think it’s highly likely that synthetic fuel is going to become more common, as a lot of us know that ICE vehicles suit our lifestyles and needs best (tradies, for example), who can’t afford to take large chunks out of their working days to recharge, travel a lot and need something that will take all the gear needed for their work.  This is because Formula 1 racing is planning to use it to power all its ICE racing cars, hopefully by 2026.  We’ve seen a lot of technology that started off in the racing world making its way over to general use, so let’s keep our fingers crossed.  In addition, Porsche has bankrolled a synthetic fuel plant in Chile that uses wind power and the power-to-liquid method.  This opened at the end of last year (2022) with plans to produce 11,000 barrels of synfuel this year.

Given that Australia has a lot of sunshine and the potential for using it for either the sun-to-liquid or the power-to-liquid process (with the help of solar panels), it’s not surprising that they’re setting up a plant in Tasmania (funded by Porsche again), which is due to kick into action in 2026.  Watch this space!