Can synthetic fuel save the internal combustion engine?

Importantly, this fuel can be used in normal internal combustion engines without any modifications. If the initiative is successful, it could help save billions of old internal combustion engine (ICE) vehicles from obsolescence. Formula 2 and Formula 3 are also following in the footsteps of the big brother and are looking for cleaner fuels.

While every major carmaker is buzzing over EVs and hybrids, some — like Toyota and Porsche — are also looking at developing cleaner, more efficient internal combustion engines for their regular production models. Porsche is also setting up its own synthetic fuel manufacturing facility in Chile.

Here’s the rationale for the change in R&D focus. Manufacturing any vehicle, EV or ICE, has an environmental impact, as they all contain plastics and metals, including rare earths. By some estimates, manufacturing EVs results in more carbon emissions than manufacturing conventional ICE cars. EVs use huge lithium-ion batteries and lots of rare earths. These need to be mined and refined and have a large carbon impact.

EVs are popular because they are zero-emission and low-maintenance and because legislation supports them everywhere. In fact, the European Union is considering legislation that would only allow the sale of zero-carbon-emissions cars after 2035, and mandate steeper emissions cuts for vehicles sold from 2030-35. However, Germany has pushed to change this law to allow the sale of cars running on carbon-neutral fuels. Japan is also looking towards cleaner fuel.

It is estimated that by 2030, only about 8% of the two billion vehicles on the road will be purely electric. The vast majority will still be ICE vehicles. The problem with these vehicles isn’t the engine – it’s the fuel.

Crude oil has to be mined and refined and these processes generate huge amounts of carbon emissions. The exhaust from these vehicles also contains carbon dioxide and other toxic gases. Thus both fuel production and consumption emit carbon. However, if a synthetic ‘e-fuel’ could be manufactured – which captures ambient carbon dioxide to balance carbon emissions from exhaust – it could be carbon-neutral or even carbon-negative.

F1 is working with Aramco to produce such fuel, while Porsche is working with Siemens Energy and Exxon-Mobil. The process involves capturing ambient carbon dioxide and extracting hydrogen from sea water using renewable electricity. Hydrogen is pumped into the CO2 to produce methyl alcohol (methanol), which is converted into synthetic petrol using a process pioneered by Exxon-Mobil.

If the math pans out, the carbon emissions from this e-fuel will be less than or equal to the amount of carbon captured from the air. And if the finances are balanced, the fuel can be priced competitively. If all goes well, ICE vehicles will not have to be retired. For example, Porsche has committed to going electric or hybrid with 80% of its production, but wants to stick to ICE for its iconic 911.

However, the engineering challenges are formidable. The Porsche facility in Chile has solved the green hydrogen problem, such as by using wind power to fracturing water, as it is an excellent location for wind turbines. However, the global electrolyzer capacity for green hydrogen is far below the requirement. CO2 capture is also not very efficient. Furthermore, e-fuel is costlier to produce than petrol from crude oil and is less energy efficient than EV or conventional ICE fuel.

Making synthetic fuels cost-effective on a large scale would involve finding sites where plenty of renewable energy could be produced (perhaps harnessing geothermal and tidal as well as solar and wind). It will also require increasing efficiency in carbon capture processes and electrolyser scale. But it does offer an alternative route to sustainability. Keeping two billion vehicles in service using green fuels could have less environmental impact than replacing them.

Updated: June 08, 2023, 11:45 AM IST