Audi have successfully made diesel fuel from carbon dioxide and water

[roopi]

http://www.sciencealert.com/audi-hav...-air-and-water

[JRSC00LUDE]

Someone with a better understanding of Chemistry and such would have to explain is this is feasible for mass production/usage, has stability for storage and transport and so on. If so it could be the start of a decent game-changer down the road, no?

EDIT - a bit more reading suggests the technology has been around for a long time but not all that attractive/feasible for mass use. Audi claims to have changed that part of the process.....interesting for sure.

[spikerS]

it is all going to come down to cost. is it more cost effective to create this "E-Diesel" or to keep using fossil fuels/EV/regular diesel.

[JRSC00LUDE]

Well the line that says consumer cost is anticipated to be in the same line as traditional diesel leads one to think there may be something to it. Time will tell but like I said, interesting thing for sure.

[DTTB_36]

Isn't this just the Fischer-Tropsch process, wait that looks like its with carbon monoxide. But seriously, why the extra step when electrolysis is already being done to create H2 which is a fuel. Storage of H2 is a pain. Whats the energy equation of this "blue conversion"

[ExtraSlow]

Step one of this process is problematic currently. If you can make cheap and plentiful electricity, you are laughing. If not, this is useless.

[ryanallan]

Originally posted by DTTB_36
Isn't this just the Fischer-Tropsch process, wait that looks like its with carbon monoxide. But seriously, why the extra step when electrolysis is already being done to create H2 which is a fuel. Storage of H2 is a pain. Whats the energy equation of this "blue conversion"

My guess would be to "get rid" of the CO2. Rather than let it float around or pump it underground they can recycle it.

[DTTB_36]

You can get rid of co2 but then you are still burning fuel. This creating more emission that aren't from a large source.

[JRSC00LUDE]

Originally posted by DTTB_36
You can get rid of co2 but then you are still burning fuel. This creating more emission that aren't from a large source.

Well they use carbon dioxide to create the product but presumably, some is released when it is burned so I guess the real question is, is the net impact a negative, neutral or positive figure? If it's either of the first 2 then it's an improvement is it not?

I find this concept interesting, if there are ways to eventually mass produce the fuel using renewable energy sources/heat capture from production/etc., one would think there is potential to become something significant while still allowing the evil oil/gas companies to transition into a business that would maintain profits while improving sustainability. Obviously it would be a long term thing but a start is something.

Or I'm being too simplistic/idealistic about it.

[Sugarphreak]

...

[JustinL]

Originally posted by ExtraSlow
Step one of this process is problematic currently. If you can make cheap and plentiful electricity, you are laughing. If not, this is useless.

I think this is the crux of the matter. Diesel in this case is just being used as a storage medium for energy. The power source is ultimately electricity for wind/nuclear/coal. The advantage of diesel is its energy density compared to H2, existing diesel vehicles, and existing infrastructure. It should be a net-zero CO2 process in theory, but the big problem is that unless the conversion is super efficient the amount of diesel produced per unit of energy input might be way too costly. It also starts to not be C02 neutral if you burn coal to make e-diesel.

[jacky4566]

JustinL i think you should check your facts.
Hydrogen contains three times more energy than diesel.
On the other hand, hydrogen is difficult to store because of its naturally low density. At atmospheric pressure and room temperature, it takes a volume of 11 m3 to store 1 kg of H2. Current storage technologies compress the gas at high pressure (700 bars) or liquefy hydrogen at -253 °C, which generates additional risks.

The article quotes the e-diesel will sell to the public for between 1 and 1.50 Euros per litre. But I will believe it when I see it.

[JustinL]

Originally posted by jacky4566
JustinL i think you should check your facts.

Yes per Kg, hydrogen is more energy dense, but even in liquid state is 4 times less energy dense per litre.

Here's a nice list of energy densities. We should be using the MJ/L because tank volume is the limiting factor for vehicles and not mass. http://en.wikipedia.org/wiki/Energy_density

Liquid hydrogen is 8.5 MJ/L
Diesel is 35.8 MJ/L

To get the same energy into a liquid hydrogen car tank as a 50L diesel tank, you would need a 210L liquid hydrogen tank+ associated cryo.

[ExtraSlow]

I think Justin has covered that excellently. Space is the problem, not mass.