Audi making diesel from water, CO2, and electricity.

sounds like more bull$#!t

 

All this trouble just to keep alive the old diesel engine?
In efficiency I assume they meant 'conversion', what about an energy balance?

 

Energy balance is quite good, but the process is expensive. The least expensive process here in terms of dollar per mile would be to make methanol (its made during this process) and to burn it in a flex fuel hybrid.

Why the fuss, and how can you make money at it? We have a lot of interest in gas to liquids (GTL) like this using natural gas. The problem is building the plants require long term of spread between natural gas costs and diesel costs to make money.

Could Turning Natural Gas Into Liquids Be the Next Big Thing?


If audi can use methane from renewable electricity, it can like have governments lock in the prices. It does make more sense than some of the renewable hydrogen schemes we have been seeing lately. The tech is proven, but the cost of the electricity + the cost of the plant needs to be competitive with the price of diesel.

 

The part that bothers me is the synthesis, its like capturing CO2 just to emit it back in a dirty way of local pollution (Sulphur present or not). The diesel combustion technology is a proven one, that does not say its a good one.

 

IMHO audi is really just pulling the numbers on hydrogen. You can really for only about $11B (current plant being built in the US) covert methane (biogas or natural gas) or hydrogen to diesel. Once you have diesel it can flow in the same infrastructure that diesel flows in today. You don't need to change the cars, you don't need to change to pumps, all you need to do is build the equipment to upgrade methane or hydrogen to diesel. As a bonus the unhealthy pollution drops in those existing cars because the diesel has less aeromatics and sulfur that can cause pollution in diesel vehicles.

Now we have a problem. Low oil prices mean that the diesel going to cost more made from natural gas or renewables than from oil.
Citing lower oil prices, Sasol delays Louisiana GTL plant investment - Oil & Gas Journal
But the solution is to make these plants subsidied and run on renewables. well at least according to audi. Sometime in the future rnewables will cost less than natural gas and oil, maybe..... But low oil prices make unsubsidied hydrogen look really bad. If you can put 7.5 gallons of gas in a camry hybrid for $19, but it cost $40 to fill up a mirai to go the same distance, then a lot of people will say the hybrid is clean enough, and buy the car that costs less to buy, run, and is faster, etc.

But we can make diesel from hydrogen. We can also make methanol much cheaper than diesel with lower investment. That would require an open fuel standard, which might make cars cost $100 more each, but you could pretty cheaply put renewable methanol in a hybrid with not many changes.

 

Never heard of the "1450 deg F high temp electrolysis process" but if that is a good process, the implication would be green H2 that Toyota could used for FCV.

Overall there are all kinds of exciting chemistry out there, the big questions are can it be scaled up? can it be ecomomical? and Does anyone care? What I mean is sometimes you can have technical success, economc success and still there are alternates that are better or just simply preferences, and not invented here attitudes and royalty issues etc. Bottom line I am not buying stock in Audi yet but I like the work. Sounds maybe better than some of the defunct alternate fuels plants we tried to get going in the US.

As far as synthetic diesel that is not a new idea. Fisher Tropsch process has been around since WWII or before and is used (eg; by South Africa/Sasol as per AG) to combine H2 and carbon oxides into diesels. They start with coal but the idea of combining H2 and carbon oxides to make (paraffinic nice diesel) is out there for a long time. If there is an improvement fine that is great, FT is somewhat difficult and expensive process ...but I am not yet hearing that chemcial community is celebrating that Audi finally figured out a better way to do it after all these years.

 

On average, only 3 trucks are passing the street where I live a day and no train no ship, so I am speaking about passenger cars.
If modern diesels are so clean how comes France says diesel cars are a mistake and announces phase-out plans? and this despite of their car industry lobby? And I hear now the UK is starting to take measures in this direction as well.

 

On the other hand, if modern diesels are as polluting as European politicians suggest, why did lab rats experience virtually no health effects from nearly constant exposure (80 hours/week) to concentrated exhaust from a 2007-compliant diesel truck engine over the normal lifespan of the rats (~30 months)?

http://www.healtheffects.org/Pubs/Press%20Release%20ACES%202015.pdf

The exhaust to which the lab rats were exposed in the "high exposure" chamber was so concentrated that it had to be cooled to keep temps in the chamber tolerable for the rats.

And the latest diesel technology (DPF+SCR) is even cleaner than the 2007-compliant engines.

http://www.healtheffects.org/Pubs/ACES-Phase2-Final-Press-Release-120413.pdf

 

Audi's current e-gas or renewable methane uses what us's NREL says is the least expensive renewable hydrogen. They are using off peak wind. They are producing enough methane to power about 1500 cars, and at this small scale the equipment is probably more expensive than they are saving in efficiency. To build that gtl plant to take the methane to diesel you probably need to make enough to supply 1M cars.

Which is a problem with hydrogen. If you are producing it centrally it can't use existing infrastructure, you need to liquify it and truck it out to the stations, or go low scale at each station. If you are only going to supply 100 cars a day, you want to do it with the cheapest electrolysis equipment, not the most efficient, because equipment costs make a big difference. So this really is a competing idea fuel cell vehicles. A way to use existing infrastructure to add renewables to traditional cars.

Additionally if we are talking europe, the cheapest way to make this no fossil fuel methane would be in france's nuclear power plants. Waste heat could be used to make this process more than 70% efficient. I don't think that would pass the smell test for environmentalists in germany, but it would be less expensive. Depending on Russia for natural gas, does add aditional incentives to producing biogas and methane through electricity.

 

Don't ask me, ask the World Health Organization this question.
Maybe rats are not human?
I certainly do not want my grandchildren to be the 'lab rats' in the real world.

 

WHO was studying diesels that do worse than the 2007 car standardard. Many of these are running today in older cars, and in trucks and diesel generators that don't have to conform.

The euro 6 and epa standards for diesels are pretty clean,often cleaner per mile than the average gasoline vehicle. There are many old ones also. The idea of non -fossil diesel fuel would burn cleaner in these old engines, but the best thing for the environment is to pull the old diesels off the roads.

Audi and the other german automakers (BMW, mercedes) are fighting politically to keep their lead in diesels as a low ghg fuel. This new fuel, although more expensive today than fossil oil based diesel, is a way to say to the politicians there is a way

Even comparing to epa this sort of makes sense a bmw 328d gets 37mpg combined epa, a much slower clarity gets 59 miles/kg. Audi is saying this takes about 49 kwh to make a gallon of diesel. If the hydrogen takes 60kwh (higher because it needs to be compressed distributed and dispensed) then the diesel will require about 30% more renewable electricity. The diesel would probably cost less at the pump before subsides becaue it would cost less to build the extra wind turbines and ptl plants than the hydrogen stations. Audi is also pursuing plug-in technology. That bmw would need 3.9x as many wind turnbines as a teslas 70d to go the same distance and superchargers are cheaper than ptl plants.

German power prices negative over weekend – German Energy Transition
When prices go negative, which happens at high wind on nights or weekends, making e-gas or e-diesel makes sense. Low cost off peak electricity being used to produce methanol, e-gas (methane), and other liquid fuels may make a lot more sense than using palm, canola, and soybean oil for biodiesel.

 

@austingreen
Take France as an example (90% non carbon electricity): can you think of one aspect in which modern Euro6 diesel passenger car has an advantage over plug-in car there? Will you agree that for France the current move by the government is the right one?
There are better alternatives to diesel engine for small cars, everywhere.
Diesel cycle is intrinsically dirty, in order to pass today's standards it needs several different after combustion treatments, my fear is that these are acceptable when the car is new but 4-5 years on the road with this car - who knows.

 

Haven't seen emission result from this specific fuel (e-diesel), but synthetic diesel fuels are typically lower in emissions than petroleum-based diesel fuel.

For example, hydrotreated vegetable oil ("renewable diesel") , which is becoming commercially available in California, has lower emissions across-the-board.

About Diesel HPR | Propel Diesel HPR

Dimethyl ether (DME) burns so cleanly in diesel engines that no after-treatment is required to meet current emissions regs other than an oxidation catalyst. So it's really the fuel that's the problem, not the Diesel cycle.

 

My PIP is refueled as quick as any diesel car (in fact - quicker due to the smaller tank for same range).
I am refueling electricity only when time is on my side, never sat (or stood) waiting for charging to finish.

What puzzles me is why, in Europe, plug-ins penetration is so low giving the huge cost advantage of electricity due to extremely high taxation on gasoline and solar fuel.

 

I am not saying that at all.

Certainly plug-in incentives in france make sense.
The pro-diesel program then the anti-diesel program seem a great deal of thrashing.
Paris mayor announces plans to ban diesel cars from French capital by 2020 | World news | The Guardian
I like the idea of putting stickers on the most polluting cars. They might replace the diesels faster if they encourage euro 6 instead of treating most diesels the same.

Agree here that most small, low mileage a year cars don't really make much sense as diesels. The pollution control costs too much relatively to fuel savings. France has so many diesels because the government had encouraged them with tax policies.

Here we have emissions tests to make sure car pollution control are working properly, that can apply there if the tailpipe pollution is their main concern.