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Bosch on importance of renewable synthetic fuels to reach climate goals; e-fuels

The Paris Agreement calls for global warming to be limited to 2 ˚C above pre-industrial levels, and preferably 1.5 °C. The fossil CO₂ emitted by road vehicles will have to be reduced to nearly zero over the next three decades for that to happen—a daunting and complex challenge.

Electromobility is just now picking up momentum; further, electric cars are only as emissions-free as the production of electricity that charges their batteries. In addition, around half the vehicles that will be on the road in 2030 have already been sold—most with gasoline or diesel engines. Legacy vehicles will also have to play their part in cutting CO₂ emissions. One path to achieving this is with renewable synthetic fuels (e-fuels). Bosch outlines seven reasons why renewable synthetic fuels should be part of tomorrow’s mobility mix:

  • Time. Renewable synthetic fuels have long since left the basic research phase. Technically speaking, it is already possible to manufacture synthetic fuels. First, apply electricity generated from renewable sources to obtain hydrogen from water. Then add carbon. Finally, combine CO₂ and H₂ to make synthetic gasoline, diesel, gas, or kerosene.

    The production process is viable, but capacity is lacking. It has to be expanded rapidly to meet demand. Incentives could come from fuel quotas, offsetting CO₂ savings against fleet consumption, and long-term planning certainty.

  • Climate neutrality. As their name suggests, renewable synthetic fuels are made exclusively with energy obtained from renewable sources such as the sun or wind. In the best-case scenario, manufacturers capture the CO₂ needed to produce this fuel from the surrounding air, turning a greenhouse gas into a resource. This creates a virtuous cycle in which the CO₂ emitted by burning renewable synthetic fuels is reused to produce new fuels. Vehicles on the road, when powered by synthetic fuel, are ultimately climate-neutral.

  • Infrastructure and powertrain technology. The Fischer-Tropsch process produces renewable synthetic fuels that can be used with today’s infrastructure and engines. Such drop-in synthetic fuels can be deployed without first modifying infrastructure and vehicles, and they have an immediate impact and deliver faster results. They may also be added to conventional fuel to help reduce CO₂ emissions from vehicles already on the road today. This way, these fuels could contribute to the cause even before they are ramped up for larger-scale production. The chemical structures and basic properties of gasoline remain intact, so even vintage cars can run on synthetic gas.

  • Costs. Producing synthetic fuels is still a costly process. Renewable synthetic fuels will become considerably more affordable when production capacities are expanded and the cost of electricity generated from renewable sources comes down. Present studies suggest that a pure fuel cost of between €1.20 and €1.40 a liter (US$5.00 to US$5.84 per gallon) can be achieved (excluding any excise duties) by 2030, and as little €1 (US$4.17) by 2050.

    These fuels’ cost disadvantage compared with fossil fuels could be significantly reduced if value was ascribed to the environmental advantage of renewable synthetic fuels. The fact that they are compatible with today’s infrastructure and automotive technology gives them an advantage over other alternative powertrains.

  • Potential applications. Even at the point in the future when all cars and trucks are powered by batteries or fuel cells, airplanes, ships, and parts of the heavy-goods transport sector will continue to rely on conventional fuels. Combustion engines powered by carbon-neutral synthetic fuels are therefore a crucial path to explore.

  • Resources. Fuel in the tank or food on a plate—this question does not come up with synthetic electricity-based fuels. Innovative biofuels, which are, for example, produced from waste materials, are useful—however, the supply is limited. When renewable energy is used, synthetic fuels can be produced in unlimited quantities. Sufficient renewable energy can be generated worldwide to produce fuel that can then be stored and transported relatively easily.

  • Storage and transport. Renewable synthetic fuels are produced with renewable energy. This process yields a gas or liquid—making renewable synthetic fuels a good medium for storing large amounts of renewable energy and even transporting it across the globe cost-effectively.

    They can serve as a buffer for fluctuating solar or wind energy or to circumvent regional restrictions on the expansion of renewable energy production. This also affects efficiency ratings.

    A compact electric car charged in Germany with renewable electricity from Germany converts around 60% to 70% of that grid power into road performance. If the electricity comes from further afield and the energy has first to be stored in a chemical medium before being converted back into electricity, efficiency drops to 20–25%. This is the same efficiency as a vehicle run on renewable synthetic fuels.



A smart way to better use REs and greatly reduce pollution and GHGs?


Reuse carbon to reduce emissions.


You can reuse CO2 with a methanol fuel cell vehicle. CO2 produced by the FC/reformer can be stored in the methanol tank using a bladder to separate methanol and CO2. CO2 will be stored under pressure at liquid state. At the refueling station, methanol is dispensed and CO2 is returned to the station.


You can reuse CO2 from a power plant,
they make literally TONS of it every minute.


Synthetic liquid hydrocarbons are superficially attractive, but they are likely the least energy- and carbon-efficient storable product that can be made from electricity.  Being compatible with the existing fleet is okay, but many other mixes are also compatible.  Alcohols have higher energy efficiency and energy per unit carbon, and Fiat demonstrated A20 fuel recently.  And of course, direct use of electricity to charge vehicle batteries is the most efficient of all.

Since this is a changeover that will take over a decade, it makes sense to plan as if the existing fleet's requirements do not matter.  Set the future standard as a PHEV which can take anything from gasoline to E85/M85 to M100 as its liquid fuel.  Electricity goes first to PHEV charging, and then to making electrofuels.  The new-tech vehicles take pure electrofuels, and the excess gets distributed to the existing fleet as any mix up to A20.  As the old-tech fleet is retired, the need for A20 and lower-alcohol blends disappears.

This hits every point that synthetic HCs hit, without the needless waste of mandatory backwards-compatibility that won't be necessary by the time the project is finished.


If I were a purist, I would say "Anytime you opt to burn carbon in the atmosphere, no matter the kind, that polluting.


A power plant emits, a million tailpipes emit.
Use the power plant carbon for the cars, reduce emissions.


Schönau is a community in the Black Forest, Germany. They have their own grid which is connected to the other grids. Their sole source of electric energy is sourced from renewables. PV systems as well as bio-gas powered generators (PTG) and wind power mills are integrated into a functioning power grid. For nigh unto 20 years, they have been proving that what has been claimed as impossible is very possible. Their complete system is emissions neutral.


@Yoatmon, they can do it because they have a lot of biogas from, I think 2 large pig farms (as well as solar and wind). Most people don't have the biogas.
You can go so far with solar and wind, but you need a dispatchable source (such as gas (from whatever source)) to balance it.
But if every sunny place put in solar, and every windy place put in Windmills, we'd be a lot better off. (Especially as solar is now so cheap).


All the English-language links about Schönau appear to be 404, and Google Translate no longer works on entire web pages or PDFs.

If the pig-farm claim is correct, Schönau is just importing energy as pig feed and converting part of a nominal waste product into heat and electricity.  The storage problem is outsourced to grain farmers.  It is not a solution to anything because it cannot scale.

Electrofuels from air-captured CO2 can scale, but they are going to be very expensive.


All the arguments put forth in this article are so weak and wrong in the context of climate emergency. Engineer-Poet has good puts, to which I would like to add:
(1) Going towards zero emissions via BEV, not 50% as these fuel do, is essential to drawdown CO2
(2) In 1000 years, if CO2 PPM is too low and we still don't have better tech, this will make sense, i.e. probably never.
(3) Who is funding this useless research?

I propose this totally feasible transportation emergency action:
(1) Ban non-hybrid vehicle sales after 2023
(2) Require ALL new vehicles to have a minimum electric only range of 50 miles to cover 95% of needs. Commercial use should be a higher standard to not leave any low level loopholes.
(3) Carbon Fee and dividends ASAP to reflect the true external cost of removing CO2 from air.


My view is that you don't have to get to 100% renewable electricity because this is incredibly expensive and not necessary.
You should be able to get to 60/70% using wind and solar, maybe a bit extra with storage and if you have hydro, use it.
After that go for long haul transmission and fill the gaps with gas, be it biogas or fossil gas.
As for cars, hybrids or better, (PHEVs). 50 miles is too many (too expensive) for a PHEV, 20-30 will do. Make it easy to charge at your place of work / college / whatever.
Most people only drive 30 or less miles / day. Do the long runs on fossil fuel (or get a train / bus if feasible).
Aviation will be much harder due to the weight of batteries. Maybe fly a bit slower (450 rather than 500 knots). Use larger capacity planes optimised for shorter (say 4500 Nm) ranges (not 8000 as with the A350 / B777X).

Account Deleted

Schönau biogas comes from the "paper mill Palm GmbH & Co. KG, where we source our biogas, converts raw paper into corrugated board and cardboard for further processing. In paper processing, wheat starch and organic acids dissolve out of the waste paper and accumulate in the process water." Reference: is in German.


@ mahonj: When resorting to PTG, if sufficient surplus renewable energy is available, you can synthesize methane - drawing CO2 from the atmosphere letting it react with H2 produced via electrolysis - and store and use the gas as necessary. In this manner, the intermittent phases resulting from gaps of solar and wind can be overcome.

Thomas Pedersen

Take it from someone who believes their future to be in electrofuels (me...):

There is not nearly enough non-fossil CO2-sources available to supply more than a small fraction of the automotive fuels. We need nearly all the non-fossil (cement, biomass, waste) CO2 we can reasonably scrounge up for jet fuel and plastics. Because it is highly unlikely that all those point sources become fit with carbon capture or are located in places where it's convenient to transport them to synthetic fuel production sites.

Moreover, the electricity-to-mechanical motion efficiency of battery vehicles is 4-7 times higher than electricity-to-gasoline-to-shaft-power, meaning that the cost gap would be insurmountable.

Third, the time it takes to construct thousands of those plants would make VW's introduction of the ID.3 seem like the blink of an eye.

And I hope no one is suggesting we should keep burning coal to get 'clean' electrofuels?


gryf, if the paper mill is the primary biomass source then the outside source of energy and storage becomes the forestry industry rather than grain farming.  SSDD.  Methane looks good superficially and can be stored in old gas wells, but you take a very big energy loss if you make it from CO2 and H2.  There's a reason I prefer alcohols.

Tom Pedersen, if you can electrify 2/3 of your transport energy requirements your carbon-capture requirements for the remainder are suddenly much more manageable.  Do the math, you'll be pleasantly surprised.

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