Are Synthetic Fuels Really All They're Cracked Up to Be?

With emissions regulations encouraging automakers to pivot toward tiny engines and all-electric vehicles, some have likewise expressed a renewed interest in synthetic fuels. German brands, particularly Porsche, have been stressing the importance of “e-fuels” and Subaru recently announced plans to run the 2024 Super Taikyu Series using a WRX converted to run on synthetic fuels “making internal combustion engines more environmentally friendly.”

But the concept isn’t exactly a new one, leading many to question how sustainable it actually is.

Synthetic fuels first took off in Germany ahead of World War I as the demand for energy spiked across the region. By the early 1920s, the nation had several methods of transforming solid coal and natural gas into liquid fuels and they were improved until Germany could produce enough to help offset the spiking demand ahead of the Second World War and the mechanization of its military. The programs not only resulted in synthetic diesel or gasoline that could be used on an array of vehicles (including airplanes), they also became the country’s main source of lubricants, rubber, and methanol, with the leftover chemicals often being re-adapted for use in explosive compounds.

By 1944, Allied forces had cut the majority of Germany’s supply lines. Oil imports evaporated and the need to produce fuels from bituminous coal became even more important for the war effort. After the war, the United States (which had also been working on synthetic fuels) would continue these programs with much of the technology being leveraged to improve natural oil refinement and processing methods. However, interest waned as additional oil reserves were discovered in the United States — reducing the profitability of synthetic fuels and reducing government support by the 1960s.

Ethanol is even older and has been used as a fuel the world over since the 1800s. In the United States, prohibition made it less popular for general use due to a denaturing process designed to make it undrinkable in 1919. But it remained a popular solvent and saw increased use as an additive to gasoline. When prohibition ended, normal production resumed and even ramped up to address mounting energy needs ahead of World War II.

Interest declined as oil production ramped up. But the gas crisis of the 1970s resulted in the U.S. once again looking to ethanol as an alternative energy source. While it was prone toward breaking down faster in gasoline, it could be produced using fermented crops and would eventually begin to be incorporated into pump gasoline in limited quantities. By the 1990s, customers around the world could even purchase E85 straight from the pump. This ironically brought the ethanol full circle after 100 years of automotive development.

The reason for the history lesson is to point out how the history of alternative fuels has had ups and downs. It also has to be said that synthetic fuels are actually an array of products that have been around for far longer than the relevant industries tend to publicize. Unless gasoline/diesel becomes prohibitively difficult to source, synthetic fuels tend to remain relegated as a supplemental energy source.

Germany has long been interested in them because it’s an industrialized nation that has access to coal, with oil being much harder to come by. We also see this in Japan, which might explain why the country seems so interested in hydrogen powered automobiles when nobody else seems to be.

However, the real legacy of synthetic fuels seems to be providing new solutions for how we make products from cracked hydrocarbons. Goods that once stemmed exclusively from the byproducts of petroleum. But there’s still a lot of overlap between the two, as synthetic polymers still need cracked hydrocarbons and usually use some form of fossil fuel as the source.

Porsche is trying to make the case that its synthetic fuel (which it markets as “e-fuel”) is more environmentally sound than gasoline. The pitch is that synth fuel will keep vintage automobiles, race cars, and specialty performance vehicles for rich people running as the world pivots to all-electric transportation.

Objectively speaking, synthetic fuels mimic the chemical properties as conventional gasoline and diesel. Therefore, claiming they’re vastly cleaner doesn’t make a lot of sense. You’re still breaking apart hydrocarbons to get what you need. But the upside is that synthetic fuels aren’t wholly reliant on fossil fuels, you can source them from anywhere. It doesn’t have to be something you pumped out of the ground, you could source it from material waste or even pull it out of the air.

The problem with this is that the energy required for fuel refinement is largely dependent upon its original source. Gasoline production is comparatively low energy because oil has spent millions of years sitting in the ground becoming energy dense. This is also why the first synthetic fuels were manufactured from coal and not something less energy dense, like wood pulp or sugars.

Direct air carbon capture would be the only true way to make synthetic fuels genuinely carbon neutral. Burnt fuels would release it into their atmosphere and it could then be reclaimed as the foundation for subsequent energy production. However, something like this would be so energy intensive that it's functionally impossible with the technologies currently at our disposal.

Porsche has tried to address this by noting that its e-fuel facilities use renewable energy sources. But it's undoubtedly going to need to supplement that with more traditional forms of energy if it ever plans on producing synth fuels at scale. Barring a significant increase in nuclear power, it’s hard to imagine any scenario where synthetic fuels become anywhere near as affordable as traditional gasoline.

We’ve seen this happen with the concept of hydrogen-fueled cars, too. Despite the vehicles themselves producing nothing but water as a byproduct, the energy required to produce hydrogen from electrolysis results in a net energy loss.

This may be one reason the industry has looked so favorably on all-electric vehicles. While battery packs create a lot of pollution to manufacture and dispose of, EVs (which have also been around since the 1800s) are relatively energy efficient due to their being able to source and store energy directly from the grid. This makes operational emissions highly dependent upon where the electricity is coming from. In a world where electricity becomes extremely plentiful (see: affordable) and plant emissions are low, they’re the obvious choice.

But the world remains largely dependent upon fossil fuels for energy production, especially as nuclear power has lost momentum. Batteries also suffer the same energy density problems as synthetic fuel production. The only difference is that it’s an energy storage issue, rather than one pertaining to how to extract sufficient energy from the source.

While the stated problems may be addressed as the relevant technologies improve, the fact that we’ve already spent roughly a century working on all of the above could lead one to believe that new solutions will not manifest overnight. We need to view things like synthetic fuels through a historical perspective, rather than simply taking the manufacturer at its word. But it would also be foolish to simply shelve these programs, as they’ve already yielded novel industries and may yet see a breakthrough that would allow them to totally supplant fossil fuels.

[Images: Pk_camera/Shutterstock.com, ARTFULLY PHOTOGRAPHER/Shutterstock.com, H_Ko/Shutterstock.com]

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