Engineering Explained: Are E-Fuels for Real?
The combustion engine doesn’t have to die. At least, that’s what an industry contends as it scrambles to come up with the answer for a growing problem: how to reduce carbon emissions. E-fuels, or synthetic fuels, promise to be a drop-in solution that not only keeps current cars on the road but also ensures they produce virtually zero net emissions. You have every right to be skeptical.
This story originally appeared in Volume 14 of Road & Track.
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The idea is to make liquid fuel using renewable or zero-emission energy sources. E-fuels are carbon based, much like gasoline, but they’re not extracted from underground oil reservoirs. Instead, with sunshine, wind, carbon-capture technology, and a chemistry degree, one can create a substance suitable for storage in fuel tanks and burnable in internal-combustion engines.
With e-fuels, there are two intertwined challenges: cost and efficiency. A study published in 2016 in Energy & Fuels, a journal of the American Chemical Society, estimated that the final cost of a synthetic fuel would be $3.80 to $9.20 per gallon, but that was in 2010 dollars. Adjusted for inflation, that’s $5.16 to $12.50 per gallon. Porsche, itself looking into the e-fuels business, recently stated prices eventually could settle around $7.60 per gallon or less. But just two years ago Porsche claimed costs were closer to $37 per gallon. If break-room chitchat says $5 per gallon is pricey, imagine when that same gallon costs $30. The weather wouldn’t even make it into conversation.
Price is a serious problem because of e-fuels’ lackluster energy efficiency. Say a utility plant produces a certain amount of energy for powering a car. What percentage of it will actually go to spinning wheels? That’s critical, because whether
a vehicle is electric or uses synthetic fuels, it all starts with electricity production. According to a 2020 SAE study, about 40 to 70 percent of the electricity produced will make it to the wheels of an EV. For an e-fuels car, that number is only six to 18 percent. It’s possible that an e-fueled car could require 10 times more energy than an electric car to travel the same distance.
Efficiency correlates with cost. Driving becomes more expensive as more electricity is needed, regardless of where it comes from or how a vehicle uses it. Are people willing to spend more simply to continue driving combustion cars? For some, the answer is yes; V-8 engines are glorious and create a worthy sound. But generally, people hate high gas prices. That alone should create skepticism about the broad-scale adoption of synthetic fuels in passenger cars.
Yet e-fuels should have plenty of applications to prove their worth. A major advantage of synthetic fuels, much like gasoline, is incredibly high energy density. You can pack a lot of bang into a small space, and they weigh very little in comparison to hefty lithium-ion battery packs. For industries like aviation, synthetic fuel may be one of the easiest methods of curbing emissions.
E-fuels could help racing series continue the spectacle of roaring motorsport with a reduced carbon footprint. For the public, $30 per gallon is an extraordinary price, but to a Formula 1 team, the expense is laughably minor. In fact, Formula 1 has stated it’ll be net zero carbon by 2030 with 100 percent sustainable fuel by 2026. The series even noted that most road cars around the world could use this fuel. I’ll start saving now.
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