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Audi Running on GTL SynFuel at Davos

Audi’s GTL-fueled A8s.

Audi, which is providing the chauffeur service at the World Economic Forum (WEF) Annual Meeting 2007, 23rd to 28th January in Davos, Switzerland, is running ten of its Audi A8 fleet there solely on Shell’s Gas-to-Liquids “SynFuel” diesel.

All 80 of the long-wheelbase luxury A8s in Audi’s Davos fleet are fitted with 4.2-liter diesel engines, which generate 240 kW (322 hp) of power with fuel consumption of 9.4 liters/100km (25 mpg US). The total fleet provided by Audi for the WEF consists of 172 vehicles.

The Fischer-Tropsch-derived GTL SynFuel is free of sulphur and aromatics. Compared to conventional diesel, soot is reduced by 35%; carbon monoxide emissions by no less than 93%; NOxby up to 9%; and carbon dioxide (CO2) emissions go down by around five%. The fuel can be used for all diesel-engined Audi models without any retrofitting measures.

Audi has already tested SynFuel under racing conditions. At the Le Mans 24 Hours of 2006, the race-winning Audi R10 with TDI engine was filled with a SynFuel blend.

Fuel Properties
Property Diesel Shell GTL
Density [kg/m3] 830 780
Net heat of combustion [MJ/kg] 42.5 43.99
Aromatics content [%-w] 20.6 0
Carbon content [%-w] 86.3 84.9
Sulfur content [ppm] <10 0
Initial boiling point [°C] 220 197
Final boiling point [°C] 360 358
Cetane number 53 80



Rafael Seidl

The problem isn't so much the diesel as fuel-guzzlers like the A8.

andrew rose

no if it was a fleet of hybrids ie prius then I would be impressed , but hey that would send all the wrong messages would¨nt it !


Stop moaning, Prius's (Prii?) are not luxury cars. They would be no good for this role.


I'd be more impressed if the VIPs rode to the meeting on bicycles. That would be like politicians actually fighting in the wars they created. I recall at the last G8 conference the limos ran on cellulosic ethanol from Canada but not much seems to have happened since. Meanwhile GCC readers have virtual conferences such as this via email.

Silvio Berlusconi

Would a big ass fat bureaucratic even fit in a Prius? A bicycle-base vehicle would need to be a three wheeled trike with motorcycle tires, electric assist, and a bench seat, to handle the weight and lack of physical endurance or strength. Bureaucrats resemble the stuffed sausages that they so readily consume during taxpayer funded lunches and dinners.

John Baldwin

Well to wheel CO2 is very bad for GTL.

To make liquid out of gas is very difficult and both energy and CO2 expensive.....

Transportation needs to take into account the cost of making the fuel if we are to have any chance of reducing CO2 emissions....


John Baldwin,

one important raw material of synfuel is or could be flare gas. thus, how could synfuel increase CO2 emissions?

Paul Dietz

Well to wheel CO2 is very bad for GTL.

Even if the extra CO2 at the plant is sequestered?

John Baldwin


I do not believe that any of the places that make synfuel actually flare gas - they either use it to help produce more oil or turn it into LNG (certainly thats what Qatar does). I'm not aware of any Syngas project that is using gas that would be flared.

Paul - nor am I aware of any Synfuel plant that is even considering sequestering the CO2. These plants are already very very complex, I can't imagine that as well!!

Rafael Seidl

Afaik, xTL technologies all depend on either Fischer-Tropsch or the harder-to-control MTG process. Both take synthesis gas and use exothermic reactions to produce a mix of hydrocarbons, mostly alkane isomers. One research objective is to increase the selectivity of the compounds created to avoid getting stuck with too much that is hard to sell (or needs to be recycled into the gasifier).

A second useful approach is to use the substantial process heat to drive a regular steam cycle power plant. The electricity produced can be used to satisfy local demand and/or industrial processes such as aluminium smelting. Places like Bintulu, Malaysia or Qatar are politically stable enough to warrant the investment of setting up such a plant.

Also, xTL processes based on fossil fuels (gas, coal, tar sands) can be seen as stepping stones towards those that use renewable feedstocks (biomass, household waste).

Increasing the use of aluminium in vehicle components is one way to manage total vehicle weight and hence, fuel consumption due to acceleration and hill climbing.

Paul Dietz

Paul - nor am I aware of any Synfuel plant that is even considering sequestering the CO2. These plants are already very very complex, I can't imagine that as well!!

There is already a synthetic fuel plant (not xTL, but synthetic methane) that sends its CO2 off for sequestration -- the Great Plains plant in North Dakota. The CO2 is piped to Canada to stimulate oil production.

As for 'even considering' -- I have seen sequestration mentioned in the descriptions of many CTL plans. You'd extract excess CO2 from the syngas before sending it to the FT reactor. This could save some money in that the FT reactor could be smaller (with less catalyst) or operate at a lower pressure.

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