Can Synthetic Fuels Save the Combustion Engine?

Introduction: The Combustion Engine’s Uncertain Future

For over a century, the internal combustion engine (ICE) has been the backbone of global transportation, powering cars, trucks, ships, and airplanes. However, with growing concerns over climate change, tightening emissions regulations, and the rapid rise of electric vehicles (EVs), the future of traditional gasoline and diesel engines appears uncertain. Governments worldwide are setting ambitious targets to phase out fossil fuel-powered vehicles, with some countries aiming for full electrification within the next few decades.

Yet, amidst this shift toward battery-powered mobility, a potential lifeline for the combustion engine has emerged: synthetic fuels. These carbon-neutral alternatives promise to keep ICE vehicles on the road while drastically reducing their environmental impact. But can synthetic fuels truly save the combustion engine, or are they merely a temporary solution in an electrified future?

What Are Synthetic Fuels?

Synthetic fuels, also known as e-fuels or electrofuels, are artificially produced hydrocarbons designed to mimic conventional gasoline, diesel, or jet fuel. Unlike fossil fuels, which are extracted from the ground and release ancient carbon when burned, synthetic fuels are made using renewable energy sources, capturing carbon dioxide (CO₂) from the atmosphere or industrial processes.

There are several types of synthetic fuels, including:

1. E-fuels (Electrofuels) – Produced using renewable electricity to split water into hydrogen and oxygen (via electrolysis), then combining hydrogen with captured CO₂ to form hydrocarbons.
2. Biomass-to-Liquid (BTL) Fuels – Derived from organic materials such as agricultural waste, algae, or forestry residues.
3. Power-to-Liquid (PtL) Fuels – Similar to e-fuels but often involving more complex chemical processes to create high-energy-density fuels suitable for aviation and heavy transport.

The key advantage of synthetic fuels is that they can be carbon-neutral—when burned, they release only the CO₂ that was originally captured during production, creating a closed carbon loop.

The Case for Synthetic Fuels

1. Compatibility with Existing Infrastructure

One of the biggest hurdles in transitioning to electric vehicles is the need for massive infrastructure changes—charging networks, battery production facilities, and grid upgrades. Synthetic fuels, on the other hand, can be used in existing engines with little to no modification. Gas stations, pipelines, and distribution networks would remain largely unchanged, making adoption far simpler.

2. A Solution for Hard-to-Decarbonize Sectors

While passenger cars may transition to electric power relatively smoothly, certain industries—such as aviation, shipping, and heavy-duty trucking—face significant challenges with electrification due to energy density limitations. Synthetic fuels could provide a viable alternative, allowing long-haul trucks, cargo ships, and airplanes to operate without relying on fossil fuels.

3. Preserving Automotive Heritage and Performance

For car enthusiasts and manufacturers of high-performance vehicles, synthetic fuels offer a way to maintain the driving experience of combustion engines while meeting environmental regulations. Companies like Porsche have already invested heavily in e-fuel development, seeing it as a way to keep classic cars and sports vehicles on the road in a carbon-neutral manner.

4. Energy Storage and Grid Stability

Synthetic fuels can also serve as a form of energy storage. Excess renewable energy from wind or solar farms can be used to produce hydrogen or e-fuels, which can then be stored and transported easily—unlike electricity, which requires large-scale battery solutions.

Challenges and Limitations

Despite their promise, synthetic fuels face significant obstacles that could limit their widespread adoption.

1. High Production Costs

Currently, synthetic fuels are far more expensive to produce than conventional gasoline or diesel. The process requires large amounts of renewable electricity, advanced carbon capture technology, and complex chemical synthesis. Until production scales up and costs decrease, e-fuels may remain a niche solution.

2. Energy Inefficiency

The production of synthetic fuels is energy-intensive. Studies suggest that only about 10-20% of the original renewable electricity used in the process ends up powering the vehicle, compared to 70-90% efficiency for battery-electric vehicles. This inefficiency makes them less attractive from an energy policy perspective.

3. Competition from Electrification

With automakers investing billions in EV development and governments pushing for zero-emission mandates, synthetic fuels may struggle to gain traction. If battery technology continues to improve rapidly—offering longer ranges, faster charging, and lower costs—the demand for combustion engines, even those running on e-fuels, could diminish.

4. Limited Carbon Neutrality in Practice

While synthetic fuels are theoretically carbon-neutral, their environmental benefits depend entirely on the source of energy used in production. If fossil fuels power the synthesis process, the net carbon reduction could be minimal. True sustainability requires 100% renewable energy inputs, which are not yet universally available.

Industry and Government Responses

Several major players are already exploring synthetic fuels as part of the energy transition:

• Porsche has invested $75 million in HIF Global, a company producing e-fuels in Chile using wind power.
• Audi, BMW, and Mazda have also expressed interest in e-fuels as a complementary solution to electrification.
• The European Union has included e-fuels in its climate strategy, with debates over whether they should be allowed in new vehicles beyond 2035.
• Aviation and Shipping Industries are heavily researching synthetic fuels as a way to meet emissions targets without abandoning combustion engines entirely.

However, critics argue that synthetic fuels should be reserved for sectors where electrification is impractical, rather than prolonging the life of passenger car combustion engines.

Conclusion: A Bridge, Not a Savior?

Synthetic fuels present a fascinating paradox—they offer a way to preserve the combustion engine while reducing its environmental impact, yet they may not be the ultimate solution for a zero-emission future. Their best application may lie in sectors where electrification is difficult, such as aviation and heavy industry, rather than mainstream passenger vehicles.

For now, synthetic fuels represent a bridge technology, helping to decarbonize existing engines while the world transitions to cleaner energy sources. Whether they can truly “save” the combustion engine remains uncertain, but they undoubtedly provide a valuable tool in the broader fight against climate change.

As technology advances and production scales up, synthetic fuels may carve out a sustainable niche—ensuring that even in an electrified world, the roar of a combustion engine doesn’t fade away entirely.