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Synthetic Fuels - Future Energy Sources?

Synthetic Fuels - E-Fuels - Power-to-X: Alternative fuels are seen as great hope in the transport sector. Now Porsche is also getting into the topic. The most important questions and answers.

  • Synthetic fuels are leaving the research stage

  • New impetus: Porsche is pushing ahead with testing e-fuels in the VW Group

  • The efficiency of e-fuels remains controversial and costs have to be reduced

Gasoline, diesel, electric, hydrogen, synthetic fuel:What will our cars drive in the future?A question that concerns many in connection with the current climate protection goals and has prompted the Federal Environment Ministry to support a program for the development of electricity-based fuels (Power-to-X). A competence center for research into PtX technology is being set up in the Lausitz energy region.

A new signal from the automotive industry comes from Porsche. The sports car manufacturer wants to build one Pilot plant for synthetic fuel in South America support. Porsche's goal is to use the carbon-neutral fuel in a test fleet and to develop it for use in existing vehicles.

Why are synthetic fuels being developed?

With theParis climate agreementthe global community has agreed on climate protection goals that have far-reaching consequences:Fossil energy is to be replaced by renewable energy.That means: Ships are no longer allowed to run on heavy fuel oil, planes can no longer fly on kerosene and vehicles with internal combustion engines should give way to electric cars. The target is the year 2050. But what if there is one tomorrowfuelthere would beburns clean, affordableandproduced in a climate-neutral way becomes? Could you continue to drive conventionally with it without affecting the climate? To clarify this, researchers have been trying for many years to develop a wide variety of synthetic fuels.

ADAC: Great opportunities for alternative fuels

In the long term, the ADAC relies on e-fuels and hydrogen from renewable sources. The good storage capacity and synergy effects in the context of the sector coupling of electricity, heating market and transport speak in favor of both alternative fuels.

ADAC Technology President Karsten Schulze says: “Millions of combustion engines are on the German roads and they still have a long service life ahead of them. If the Climate protection goals in traffic are to be achieved, a solution is needed for this inventory. "

Apparently the Ministry of Transport also sees it that way. It announced in January 2021 Funding program for renewable fuels. Around 1.54 billion euros are available for this until 2024. According to the ministry, 640 million euros of this will flow into development and demonstration projects for the production of renewable fuels. Another 900 million euros are available for retrofitting or building new generation plants and for the market launch of biofuels and electricity-based fuels.

What are synthetic fuels made of?

Initially, researchers had investigated whether or notrenewable raw materialslike corn, rapeseed, wheat and palm oilFuels for gasoline and diesel engines let generate. But it quickly became apparent that this was followed by considerable environmental problems. In Asia and South America, for example, primeval forests were and are being cleared for palm oil plantations. Primarily for cosmetics and food, but also for fuel additives.

After unsuccessful attempts with waste, residues or algae, experts are now working with synthetic fuels that onHydrogen as a basic product put. Because hydrogen has the decisive advantage of being almost infinitely available in nature and that it can also be produced in a climate-neutral manner. And since hydrogen is released by electrolysis of water with the help of (regenerative!) Electricity, scientists are talking about "electricity-based fuels" or ofE-fuels orPower-to-X.

What are the advantages of e-fuels?

Hydrogen and all hydrogen-based e-fuels can practicallywithout quantity limitand compared to conventional gasoline and dieselburn quite cleanly. Ideally, they could also be used in existing vehicles, i.e. gasoline and diesel cars. In order to prevent damage to the engines in existing vehicles, the properties of synthetic fuels must be within the standards for diesel and gasoline. There is now an extra standard for them: EN 15940. Ideally, e-fuels would be based on theexisting petrol station network expelled. Engines in new vehicles would have to be designed for synthetic fuel.

How are e-fuels made?

First of all, you needrenewable electricity - preferably excessWind or solar power,which the network cannot accommodate. This splits water into oxygen (O₂) and hydrogen (H₂) by electrolysis - this results in hydrogen as the first raw material. In the second step thisHydrogen with carbon dioxide (CO₂)which, for example, falls as a waste product from other industrial processes or is extracted from the ambient air.

PossibleThe end products are synthetic diesel, synthetic gasoline and synthetic gas.Production is currently still taking place in small quantities, for example in research and pilot projects. The best-known system is in Werlte, northern Germany, where Audi and industrial partners are producing climate-neutral,synthetic e-gasproduced. This is fed into the normal natural gas network and offset against the quantities that customers of Audi or the VW Group fill up in their natural gas vehicles. Electricity-based gasoline and electricity-based diesel are not currently being marketed.

How efficient are e-fuels?

Due to the numerous individual steps involved in the production of e-fuelshigh loss of effectivenessat. In the "well-to-wheel" analysis, only 10 to 15 percent of the energy used in the process is left at the end. For comparison: In an electric car, 70 to 80 percent of the output energy reaches the wheel. And therefore of course the question arises as to whether it makes sense, which can only be answered positively when using additionally generated regenerative electricity.

Another topic: The generation of renewable electricity fluctuates greatly and is independent of demand, soconsiderable capacities are required to store electricity are. In this context, the question of whether hydrogen offers the optimal storage technology is also being discussed. Of course, hydrogen in its pure form could also be used as direct fuel in internal combustion engines. BMW, for example, has already developed a hydrogen combustion engine in the BMW 7 Series to readiness for series production, but has discontinued the project due to storage problems in the car.

What would synthetic fuel cost?

As of today, one liter of synthetic fuel would be around4.50 euros in production due. Optimistic forecasts such as those of the Wuppertal Institute assume that theYear 2030 a price of 2.29 euros including taxes would be possible. One thing is clear: despite the general increase in ecological awareness, most customers will only accept e-fuels if the price is right. And for this it will be important which taxes the state applies to these fuels and how much fuel the cars then use in everyday operation.

When and where can e-fuel be expected as a fuel?

The speak against an early market launch on a broad frontpoor efficiency, the elaborate, so expensive manufacture andlack of industrial facilities. Experts see the area of ​​application of e-fuels not in cars, but in Transport areas, where neither an electric nor a fuel cell drive can be used. That would be above all in planes and shipsthe case. The reason: one would have to carry such extremely large batteries or hydrogen tanks on airplanes or ships that too little of the transport volume would be left over. Synthetic fuels, on the other hand, do not take up more space than kerosene or diesel due to their high energy density and they also weigh no more.

What are the next steps in the research?

In onecurrent research project an attempt is made to significantly increase the efficiency in the production chain. In theory, an efficiency of up to 60 percent is possible, according to a message fromKarlsruher Institute for Technology (KIT). A central component of the test facility is a new synthesis reactor that uses significantly less process energy than before.

Which automaker is pushing ahead with testing?

As the first automobile manufacturer to have Porsche declares to promote the development of synthetic fuel. The sports car manufacturer supports the construction of a large-scale facility for the production of e-fuels. The plant is located in Chile because Chile is ideal for generating electricity from wind power. In the pilot phase, around 130,000 liters of e-fuels are to be produced in 2022. In two steps, the capacity is then to be increased to around 55 million liters of e-fuels by 2024 and to around 550 million liters per year by 2026. Porsche becomes the main buyer of the green fuel in order to test it in the fleet.

Expert interview

The Sunfire company has been researching synthetic fuels for many years. ADAC editor Wolfgang Rudschies asked Carl Berninghausen, the CEO of Sunfire, about the state of affairs.

"A price of 1.20 to 1.70 euros per liter would be possible"

Mr. Berninghausen, a lot of electricity is needed to produce synthetic fuel. You could actually use it directly in a battery. Why do you have to take this detour?
Daily distances of 80 to 120 kilometers can and should be done wonderfully with batteries. It is a different matter when cars are supposed to drive long distances. Or let's think of heavy trucks that have to carry a lot more energy with them, or planes or ships - then we come to the limits of a battery. Every truck that comes on the road stays there for 30 years! So it makes sense to find a solution for them as soon as possible to continue driving in a CO₂-neutral manner.

The efficiency in the process chain is only 15 percent, which is a devastatingly bad value.
Our technology achieves higher levels of efficiency. From the collection of the electricity to the energy on the tire, it is 20 percent or a little more. The decisive factor, however, is how more expensive the fuel will be in the end. When it is produced and distributed in Germany, electricity costs 15.16 cents per kilowatt hour, including levies of up to 30 cents. That makes the production of e-fuels far too expensive. But if you produce electric fuel in Norway, where electricity only costs 3 cents, then the bottom line is that it is cheaper to drive with electric fuel than with the electricity charged here.

What will a liter of e-fuel cost then?
The most recent studies - without taxes - come in at between € 1.20 and € 1.70 per liter.

Is there any evidence that e-fuels can be used in existing engines without damaging them?
Yes, Total Excellium or Shell V Power have exactly the same properties; both are designer fuels made by breaking down fossil natural gas into its components and then putting them back together. With us, these two components are not obtained from natural gas, but from carbon dioxide and water. But in the end they are exactly the same. The fuel can be mixed and made available to all combustion vehicles.

When do you go into production?
We want to have a plant with an annual production of ten million liters completed in Norway by the end of 2022.

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