Why the future of synthetic fuels depends on green hydrogen

To the left of the Sans-Plomb 98, to the right of the e-fuel, their chemical composition is almost identical. Photo: SDP/Porsche

Summary fuel: a solution to keep petrol cars after 2035?

Continue driving with cars with thermal motor even after 2035 is what some manufacturers dream. To achieve this, they work on synthetic fuel to be able to always use thermal engine models tomorrow.

Instead of changing your car, if we changed fuel? While Europe has almost decided to switch to 100% electric, with A goal of sales of new cars exclusively zero CO2 emissions for 2035, Some manufacturers work on alternative solutions that would continue to ride with thermal engines, without polluting too much. One of these solutions is called synthetic fuel, also called “e-fuel” or “e-carrant”.

Already old technology

A summary fuel is a fuel obtained without oil, via a chemical process from raw materials containing carbon and hydrogen. To produce it cleanly, for example, green hydrogen can be used. Hydrogen is then produced via electrolysis, to separate hydrogen and oxygen into water molecules, made with renewable electricity (solar, wind, hydraulic …) or weakly carbonated with nuclear power. For CO2, we can for example reuse the emissions of certain industrial sites by recovering carbon dioxide.

The process is not new. Some countries have in fact been already forced to produce it … for lack of oil. This was the case of Germany during the Second World War or South Africa in the 1950s and 60s, which then underwent international anti-apartheid sanctions. Summary oil was then obtained from coal, therefore with a fairly disastrous carbon footprint. The current challenge is therefore to succeed in producing it in a cleaner.

Porsche at the point on the subject

In the automotive sector, German brands are particularly interested in it. It is not for nothing that The Minister of Transport Volker Wissing Recently put on the table the hypothesis of continuing the sale of vehicles equipped with thermal engines after 2035, with as weight argument, this use of clean synthetic fuels. For him, we simply cannot count on electric on battery or hydrogen for the mobility of a relatively close future.

Porsche is particularly betting on this new technology. Last September, the brand announced “the start of the construction of the first factory in the world dedicated to the production of an almost neutral synthetic fuel in CO₂ in Chile”, in partnership with Siemens Energy, the Chilean company Highly Innovative Fuels ( HIF) but also an oil tanker like Exxonmobil, or the Italian Enel Energy Specialist.

The pilot factory is installed in Patagonia and must produce 130.000 liters of e-fuel this year, and aims at 55 million liters in 2024, 10 times more in 2026. A first use is planned as part of motorsport, with cars participating in the Porsche Mobil1 Supercup that will fill up on E-Fuel. A nice showcase, like the Formula-e for the electric.

Really ecological fuels ?

Logically, the various projects highlight promising assessments: Porsche evokes for example a reduction of 90% of CO2 emissions of fossil origin for combustion engines. In fact by freeing oneself from oil, the idea is to develop a much more effective synthetic fuel than its fossil ancestors, not containing “underied ingredients”. By avoiding burning elements like sulfur or benzene, we are already limiting polluting emissions.

The most of this technology would also be to be able to fill the reservoirs of the new but also old thermal. By keeping functional vehicles, existing, but easily reducing their CO2 emissions, the circle would then be virtuous.

But it is still difficult to assess the real impact of e-fuels. Studies have shown that the emissions of fine particles and nitrogen oxide with these e-fuelles could be strongly reduced. Other studies are more skeptical, including one of transport & environment from last December, famous for having been behind the revelations on dieselgate. For the NGO, on the CO2 side already the balance sheet is not so good, by allowing to reduce the emissions by only 40%: if we take into account the whole life cycle of the product, the electric car remains more virtuous from 60 to 75.000 kilometers traveled.

Almost 5 euros per liter today

Beyond the ecological question also arises the financial issue. At a time when fuel prices are constantly climbing, can synthetic fuel represent a cheap alternative? In its study, Transport & Environnement talks about fuel for the rich, with an additional cost estimated at 10.000 euros over 5 years if we compare with a 100% electric car.

Some estimates from future prices, with very low current production, seem to give them reason for the moment: 5 euros per liter, enough to put prices into the pump of recent days.

A study by oil tanker anticipated, however, that as in any industry, the price with a large volume process would lower costs, to 1 euro per liter by 2027 to 2030 … But we are talking about the cost of production here, which is D ‘About 0.65 cents for unleaded.

Why the future of synthetic fuels depends on green hydrogen

Synthetic fuels are on the rise. And many manufacturers, especially Germans, are counting on this technology to extend the life of vehicles with thermal engines. But for the moment, production is extremely expensive.

The Porsche-Siemens factory of Haru Oni ​​in Chile. It should produce 130.000 liters of synthetic petrol this year, 55 million in 2025 and 550 million in 2027.

Why the future of synthetic fuels depends on green hydrogen
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Summary fuels are fashionable. No wonder, because they theory the best of both worlds in theory. They make it possible to continue to use thermal motor vehicles and the infrastructures linked to them thanks to reconstituted oil fuels from neutral sources in terms of gas emissions. Volkswagen, Porsche or BMW. Some German car manufacturers are also convinced that with these synthetic fuels, they can be just as green, and even more, than electric cars. This is why they prompted their government to question the prohibition of sale in Europe from 2035 of vehicles with thermal engine. Provided obviously that they work with synthetic fuels.

It is not a miracle solution. Because they ask to be made of considerable quantities of low carbon electricity and are in the current state of extremely expensive technology.

A technology developed in Germany already

Synthetic fuel manufacturing processes, or Efuel, have long been controlled. They are inspired by the Fischer-Topsch technique of liquefaction of the coal used by Germany at the end of the Second World War to produce, for lack of oil, liquid fuels. A technology which was then improved by South Africa in apartheid, then under oil embargo, and which was recently relaunched on a small scale by China for reasons of safety.

The current process is to synthesize carbon (in the form of carbon monoxide or carbon dioxide) with green hydrogen, manufactured by electrolysis with low carbon electricity, to obtain methanol, a preliminary fuel stadium. Carbon today is no longer obtained from coal, but with CO₂ recovered and therefore which is not widespread in the atmosphere. Methanol can then be transformed with different additives into equivalent of oil fuels: petrol, diesel or kerosene.

To the left of the Sans-Plomb 98, to the right of the e-fuel, their chemical composition is almost identical. Photo: SDP/Porsche

A very competitive carbon footprint with electricity

All the calculation comes from the fact that the synthetic fuel does not emit more CO₂ that the one he captured and in addition to the heat engine vehicle due to its manufacture and recycling has a carbon footprint very lower than the batteries with batteries. The interest of the heat engine with synthetic fuel in terms of carbon footprint grows if the electricity used to recharge the batteries of electric vehicles is not very decarbonized as in China, in the United States and in several European countries including Germany.

Technically, any heat engine can drive with summary fuel without the slightest modification. It is also quite possible to mix oil and synthetic fuel in the tanks. This makes it possible to extend the lifespan of the 1.4 billion heat engine vehicles circulating today on the planet using existing infrastructure, in particular those of fuel distribution (service stations, deposits, etc.), maintenance and maintenance vehicle production.

This is theory for the possibilities offered by summary fuels. In practice, technical and economic obstacles are considerable to make them real substitutes for fossil fuels. The first is the one to which the large -scale production of green hydrogen by electrolysis and the considerable quantity of low carbon electricity is used to be used.

Very high production costs

The cost of producing synthetic fuel is therefore logically very high. This is shown by the experiment launched by Porsche in Chile in ideal conditions in its Haru Oni ​​factory. Installed on a tray at altitude swept by powerful and constant winds, it is powered by decarbonized electricity by wind turbines which operate at full capacity 280 days and nights per year against 80 on average in France. This electricity feeds electrolysers producing hydrogen combined with CO₂ captured in the atmosphere. This year, the factory should produce 750.000 liters of green methanol including 130.000 liters will be transformed into fuel. By increasing the number of wind turbines, production should reach 55 million liters of fuel in 2025 and 550 million in 2027. Interesting figures but to put in perspective with the 50 billion liters of road fuels consumed in France last year…

The difficulty today consists above all in achieving acceptable costs by producing on an industrial scale. Today, the price in the liter, of the order of $ 10, is completely prohibitive. Porsche hopes to be able to divide it by five. The Bosch equipment manufacturer who works on similar projects is more optimistic. He estimates that on 2030, the synthetic fuel could cost taxes between 1.20 and 1.40 euros per liter and 1 euro by 2050.

Finally, it should be noted that another decarbon fuel, easier to produce but less to transport and use than synthetic fuels, can also allow the life of thermal engines to be extended without emitting greenhouse gases: L ‘green hydrogen directly. Many car manufacturers in the world work on the adaptation of their hydrogen engines. This is particularly the case of BMW, which was the forerunner, but also of Toyota, Yamaha, Ford, Cummins, Kawasaki Heavy Industries, Renault Trucks and Porsche.

By Léon Thau