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Reynard38
01-19-2014, 06:00 PM
Here in Georgia, and much of the US diesel is about 20% more expensive than gasoline.
How does that compare with where you live?

slug
01-19-2014, 06:11 PM
http://www.fuel-prices-europe.info/

LeeG
01-19-2014, 08:53 PM
Here in Georgia, and much of the US diesel is about 20% more expensive than gasoline.
How does that compare with where you live?

Looks like diesel is a lot more expensive in the rest of the world than the US.

Dannybb55
01-19-2014, 08:57 PM
That is because it is lower on the cracking tower and easier to make?

Reynard38
01-19-2014, 09:27 PM
Looks like diesel is a lot more expensive in the rest of the world than the US.

With a few exceptions gasoline and diesel are more expensive compared to the US. What interests me is diesel more expensive than gasoline (petrol) in your country?

LeeG
01-19-2014, 09:39 PM
With a few exceptions gasoline and diesel are more expensive compared to the US. What interests me is diesel more expensive than gasoline (petrol) in your country?

It's evident from the link Slug gave that diesel is cheaper than gas in most countries

hokiefan
01-19-2014, 10:08 PM
It's evident from the link Slug gave that diesel is cheaper than gas in most countries

I find that interesting because diesel has almost 10% more energy per gallon than gasoline. I guess the thing I don't know is their relative quantities in crude oil. I know this can be shifted somewhat by how you run the cat-cracker, but the shift is not infinite.

Cheers,

Bobby

S/V Laura Ellen
01-19-2014, 10:15 PM
I find that interesting because diesel has almost 10% more energy per gallon than gasoline. I guess the thing I don't know is their relative quantities in crude oil. I know this can be shifted somewhat by how you run the cat-cracker, but the shift is not infinite.

Cheers,

Bobby

The price of diesel fuel has been very volatile when compared to the price of gasoline around here.

Reynard38
01-19-2014, 10:20 PM
I can remember years ago that diesel was considerably cheaper than gasoline.
Now it's more expensive than premium (high octane) gas.
Still given the choice I'd go for a diesel powered car or boat. The increase in efficiency more than makes up for the higher price per gallon.

LeeG
01-19-2014, 10:26 PM
I find that interesting because diesel has almost 10% more energy per gallon than gasoline. I guess the thing I don't know is their relative quantities in crude oil. I know this can be shifted somewhat by how you run the cat-cracker, but the shift is not infinite.

Cheers,

Bobby

I could be wrong but I think the amount of gasoline/diesel and other products you can get from crude isn't fixed, a refinery can be designed to maximize one over the other and the type of crude might produce some products more than others. Total WAG there. Also the retail price doesn't reflect the cost of the fuel before taxes. It's kind of moot, either one provides more energy than a hamburger and muscle power.

LeeG
01-19-2014, 10:29 PM
I can remember years ago that diesel was considerably cheaper than gasoline.
Now it's more expensive than premium (high octane) gas.
Still given the choice I'd go for a diesel powered car or boat. The increase in efficiency more than makes up for the higher price per gallon.

I remember that as well, worth digging into the whys and wherefores. There are good reasons for either fuel. I don't think total cost makes diesel attractive for a car.

hokiefan
01-19-2014, 11:17 PM
I could be wrong but I think the amount of gasoline/diesel and other products you can get from crude isn't fixed, a refinery can be designed to maximize one over the other and the type of crude might produce some products more than others. Total WAG there. Also the retail price doesn't reflect the cost of the fuel before taxes. It's kind of moot, either one provides more energy than a hamburger and muscle power.

Having spent most of a lifetime distilling natural raw materials I'm confident that crude is variable in the content of the various components as you suggest. I also know that the petroleum refineries use their cat-crackers and other techniques to break the great big molecules into more valuable small and medium molecules like diesel, gasoline, and many other chemicals aimed at the chemical businesses. I also know they can set things up to get more or less of various components, but there are limits on how far they can push each component. That, however, is about the limit of my knowledge. As you say, retail price isn't based on production cost, but supply and demand. Essentially its based on what the market can bear.

I just find it interesting because we used to sell byproducts into the fuel market for power generation as a replacement for heavy fuel oil. In that case our stuff was priced based on the btu content related to the price of fuel oil. In the US that was a pretty low value, a lot of effort was put into keeping the good stuff out of the fuel stream.

Cheers,

Bobby

Nicholas Carey
01-19-2014, 11:43 PM
I find that interesting because diesel has almost 10% more energy per gallon than gasoline. I guess the thing I don't know is their relative quantities in crude oil. I know this can be shifted somewhat by how you run the cat-cracker, but the shift is not infinite. Cheers, Bobby Not true. Gasoline is about 46.9 mega joules per kilogram mass; diesel (#2) about 45.8. Diesel is denser than gasoline and so ekes out an edge in terms of energy density per unit volume — gasoline is 34.6 mega joules per liter vs 38.7 for diesel.

As for production ratios,

http://www.eia.gov/energyexplained/index.cfm?page=oil_refining

http://www.eia.gov/energyexplained/images/charts/products_from_barrel_crude_oil-large.jpg

AnalogKid
01-20-2014, 12:23 AM
At the moment our diesel is about $1.50 per litre and our 91 RON unleaded petrol is $2.15 per litre.

However, petrol is taxed at the pump, but diesel has no duty and you have to get a ticket (Road User Charge, or RUC) based on kilometres driven and vehicle weight. It sort of works for commercial vehicles and it means you don't have the red-diesel for boats and agricultural vehicles and all the hassle with random excise checks that happens in the UK.

But it all falls down for private vehicles. The lowest weight band is 3 tonnes (approx 6600 pounds) and it means that its almost always cheaper to run a petrol car than a more frugal diesel. Last time I worked in out, the even point was only about 25mpg, any more efficient than that and petrol was cheaper.

hokiefan
01-20-2014, 12:28 AM
Not true. Gasoline is about 46.9 mega joules per kilogram mass; diesel (#2) about 45.8. Diesel is denser than gasoline and so ekes out an edge in terms of energy density per unit volume — gasoline is 34.6 mega joules per liter vs 38.7 for diesel.

As for production ratios,

http://www.eia.gov/energyexplained/index.cfm?page=oil_refining



Since you buy it by volume (gallons in the US) the bolded numbers are the ones that count. So 38.7 divided by 34.6 = 1.1185, actually almost 12% more. The source I used must have had slightly different values.

On a weight basis gasoline has about 2% more energy, but we don't buy auto fuel by the pound we buy it buy the gallon. And gasoline has a lower density than diesel fuel, so fewer pounds per gallon. Bottom line, in the units we purchase in, diesel has 10%+/- more energy than gasoline.

Cheers,

Bobby

LeeG
01-20-2014, 12:38 AM
Nicholas, yr both agreeing actually. Bobby said per gallon and you said per unit volume.

LeeG
01-20-2014, 12:44 AM
At the moment our diesel is about $1.50 per litre and our 91 RON unleaded petrol is $2.15 per litre.

However, petrol is taxed at the pump, but diesel has no duty and you have to get a ticket (Road User Charge, or RUC) based on kilometres driven and vehicle weight. It sort of works for commercial vehicles and it means you don't have the red-diesel for boats and agricultural vehicles and all the hassle with random excise checks that happens in the UK.

But it all falls down for private vehicles. The lowest weight band is 3 tonnes (approx 6600 pounds) and it means that its almost always cheaper to run a petrol car than a more frugal diesel. Last time I worked in out, the even point was only about 25mpg, any more efficient than that and petrol was cheaper.

I didn't know that. So it's cheaper to run a petrol car than a diesel car in NZ even though the diesel is cheaper.

AnalogKid
01-20-2014, 03:42 AM
Petrol engines tend to have higher volumetric effiency - i.e. they make more power for a given capacity than a diesel engine.

Diesels tend to have much higher thermometric efficiency - i.e. they convert more of the chemical potential energy of the fuel into kinetic energy and waste less energy as heat.

I think the difference in manufacturing costs come from 2 factors - the heavier build of diesels is required to achieve the required compression ratios for compression ignition, while in the days of modern direct injection engines, whether it be by mechanical distributor pump or common rail and electronic injection, the fuel system 'plumbing' is more complex and heavy duty on a diesel.

While a diesel version of a given vehicle tends to have better fuel economy and lower CO2 per Km (or Mile) than petrol, it does have higher particulate emissions, which aren't so great in concentrations around cities.

epoxyboy
01-20-2014, 04:53 AM
At the moment our diesel is about $1.50 per litre and our 91 RON unleaded petrol is $2.15 per litre.

However, petrol is taxed at the pump, but diesel has no duty and you have to get a ticket (Road User Charge, or RUC) based on kilometres driven and vehicle weight. It sort of works for commercial vehicles and it means you don't have the red-diesel for boats and agricultural vehicles and all the hassle with random excise checks that happens in the UK.

But it all falls down for private vehicles. The lowest weight band is 3 tonnes (approx 6600 pounds) and it means that its almost always cheaper to run a petrol car than a more frugal diesel. Last time I worked in out, the even point was only about 25mpg, any more efficient than that and petrol was cheaper.
I have just been looking at going diesel, but decided that it isnt worth it. The diesel RUC is currently $45/1000km, and the annual vehicle licence fee is almost double that of a petrol car or light truck. And when you start looking at the reliability of many mid 2000's diesels (buying new isnt an option), you quickly find that an awful lot of those earlier turbo diesels are hand grenades. Cracked heads and dodgy common rail injection systems seem to be common complaints, although good ones seem to go forever. I dont know if that is luck or good maintenance. If their electronics didnt have such a bad rep, a Mercedes CL 320 or 350 looks pretty good - the depreciation from new must be frightening, as used with 100,000km on the clock they are damn cheap for what they are. But thats a whole nuther topic.

AndyG
01-20-2014, 05:27 AM
UK: Petrol 1.29, Diesel 1.36.

Same prices here in Scotland. Meanwhile, my six-year-old Nissan Note 1.5 diesel is turning in 65-70 mpg on my daily commute. I'm delighted!

Andy

Zane Lewis
01-20-2014, 05:59 AM
re NZ and diesel cars and road user charges. crude rule of thumb here is that if you are doing more than 30000 km per year then diesel pays.
re costs, looking at the AA 2010 economy run challange over 4 days of mixed driving a subaru outback diesel finished in 21st out of 50 entries. at 19th was a Honda Jazz sport and at 20th was a Hyundai i20. the 1.8 ltr Honda civic came in at 23rd place. costs includ ruc for the diesels. the petrol outback finished in 37th place. ahead of the Hyundai i45 and 4 cylinder accords.

http://www.aa.co.nz/assets/about/events/energywise-rally/2010/ewr-2010-oct-14-results-after-day4.pdf?m=1301447591

I will say that these new common rail diesels are far less tolerant of poor quality fuels that older models. there have been a number of cases of water damage to injectors etc when filled from old or stirred up tanks. good filtration and water traps prevent this.

Zane Lewis
01-20-2014, 06:09 AM
I spoke with a number of reps in Mondeo diesels who had moved from Aussie 6 cyl and they were quite happy. also drove some myself before I took the plunge.
I got the subaru legacy 2ltr diesel, in comparison to the 2.5 lt petrol it's down 17 kw's in peak power but is actually faster to 100 kph. the power comes in much sooner 350nm 1600-2400rpm and the power curve is quite flat between 3000-4200 rpm. it does take some getting used to as you don't get that sense of building acceleration as the revs climb that a petrol gives.
Zane

Reynard38
01-20-2014, 06:27 AM
Here in Georgia vehicle tax is based on the cars value only. Weight and fuel type aren't a factor. Neither is mpg (though I think it should be).
Though the diesel version of the car we are buying is more $$, other factors make it desirable. 43 vs 32 per gallon is one. We intend to hang on to the car for a long time and the diesels typically last longer. Also the resale of the diesel versions is higher.
I looked into emission regulations in the US vs Europe. Looks like the US restricts Nitrous Oxides and the Euro regs hit CO2 hard. This favors gas engines in the US though more diesels are coming to market here. Through the use of urea injection the new diesels have greatly reduced particulate and nitrous oxide emmisions. Didn't notice ANY soot emanating from the tailpipe of the car we test drove (BMW 328d wagon).

xflow7
01-20-2014, 08:30 AM
I find that interesting because diesel has almost 10% more energy per gallon than gasoline. I guess the thing I don't know is their relative quantities in crude oil. I know this can be shifted somewhat by how you run the cat-cracker, but the shift is not infinite.

Cheers,

Bobby

This is something I've also wondered about a lot in the past - how much can the relative yield of diesel vs. gasoline be tweaked through cracking, etc.? In particular, when diesel gets touted as a way to reduce fossil fuel use. If a diesel engine is, say, 30% more fuel efficient than a gasoline engine, but a barrel of crude onlIy yields half as much diesel as gasoline, there's no savings in barrels of crude unless that ratio can be moved around a certain amount. The other consideration is that there is probably a sweet-spot for any given type of crude that maximizes the energy ratio of the resulting fuels (i.e. ratio of fuel energy content to energy required to produce). Here again, even if you can push the ratio of diesel to gasoline up, what happens to the well-to-wheel efficiency?

John Meachen
01-20-2014, 04:22 PM
To arrive at a useful comparison shouldn't we also take into account the thermal efficiency of the engine we use the fuel in?Turbo-diesels normally do better than normally aspirated diesels and most petrol/gasoline engines are a good deal less efficient.Maybe cost of fuel per mile of travel would be a useful ratio.

slug
01-20-2014, 04:38 PM
The reason Europeans drive diesel cars......http://www.enveurope.com/content/25/1/15

as well as info on pollution, global warming , co2, efficiency.


"Europe was confronted with shrinking fuel oil markets from 1970 onwards and more dramatically, after 1979, clearly reflected by oil company BP [88] sales data 1965 to 2011 which specifies the quantities of the crude oil distillation products, light distillates (gasoline, petrol), middle distillates (diesel) and fuel oil (which can be converted to diesel) sold for Europe.
The reasons for the lack of demand for middle distillates were at the least twofold. First, natural gas had increasingly pushed out fuel oil as a heating fuel at the continental European market since the mid 1960s [89]. In Germany, 18.6 million (48%) households were connected to natural gas networks by 2009 (http://www.statistica.com webcite, 2012). Then, in the 1960s in France, General de Gaulle's thrust to make nuclear the key to energy independence meant closing old power plants fuelled with middle distillates.

the need of the European oil refinery industry to place the excess fuel oil on domestic markets made the powertrain paradigm shift to diesel cars happen (for Germany [91]; for France J. Lemaire, 2012, personal communication).

Deputy mayor of Paris Denis Baupin argues [92] that Peugeot was encouraged to massively produce diesel cars in order to get rid of diesel oil overproduction. "

Garret
01-20-2014, 04:55 PM
Around here, diesel is roughly the price of premium. Also note that a BMW, Audi, VW, etc. is tested for mileage using premium & running regular will lower the mileage slightly, as the computer retards the timing to prevent pinging. On my Audi, it's not enough of a difference to make me run premium: 32 highway on regular, vs. 34 or slightly better on premium - just under 10% better mileage, but the cost of premium is about 15% higher.

BMW's new diesel is cleaner than its gas cars & particulates are not an air quality issue with it, as it has a 100,000 mile particulate filter on the exhaust. As I understand, it's a $400 replacement - which is pretty affordable considering it happens once every 100K.

Nicholas Scheuer
01-20-2014, 06:27 PM
Waste vegetable oil is still free.

Gerarddm
01-20-2014, 06:45 PM
Diesel here is the price of premium, or a bit more. I get 40MPG with my diesel, so I am happy.

Garret
01-20-2014, 08:26 PM
Waste vegetable oil is still free.

True - but it's a lot of work to filter & store. Then there's the retro-fit of the car, then you have to start on diesel & even more important, shut down after completely filling the regular fuel system with diesel (IOW, run at least 5 minutes on plain diesel). Waste oil in a 10 deg. F fuel system is not a pretty thing.

AnalogKid
01-20-2014, 08:31 PM
Neither is it a mainstream volume solution.

I think biofuels will be the solution of choice where there is no suitable alternative to internal combustion - heavy transport, military and aviation, but waste oil will only be a small-scale or DIY option.

john welsford
01-20-2014, 10:46 PM
I had to sit in my Mazda diesel pickup while it got me from Hamilton to Whangarei the other day, and had been recording fuel consumption for a couple of weeks so had the information to do a reasonably accurate comparison with the 4 cylinder Camry I used to have. Mental arithmetic helps pass the time.
Per 100 km, in NZ $s, the Mazda including road user charges costs around $14 50, the Camry about $22. No contest.
The little pickup is a 2.5 litre normally aspirated diesel, the Camry a 2.2 petrol ( gas) engine. The Camry is a lot quicker, but does not tow anywhere near as well.
I note with interest that the turbocharged common rail diesels are another leap more efficient than my old beast, quieter too.

For the USA contingent who are reading this, the way our system works means that when I put diesel in my ship, I'm paying about 2/3 the price of petrol and am not paying any road tax.

John Welsford






At the moment our diesel is about $1.50 per litre and our 91 RON unleaded petrol is $2.15 per litre.

However, petrol is taxed at the pump, but diesel has no duty and you have to get a ticket (Road User Charge, or RUC) based on kilometres driven and vehicle weight. It sort of works for commercial vehicles and it means you don't have the red-diesel for boats and agricultural vehicles and all the hassle with random excise checks that happens in the UK.

But it all falls down for private vehicles. The lowest weight band is 3 tonnes (approx 6600 pounds) and it means that its almost always cheaper to run a petrol car than a more frugal diesel. Last time I worked in out, the even point was only about 25mpg, any more efficient than that and petrol was cheaper.

Graeme Forrest
01-21-2014, 01:13 AM
I don't know where Analog has got his figures from but my experience is much closer to John. My previous car was a Nissan X-trail with a 2.0l turbo diesel, prior to that I had a 2.0l Ford Focus petrol. Shortly after purchase of the X-trail I ran a fuel cost comparison. I cannot remember the precis figures now but over 10,000 km the petrol engined Focus cost just over $1600 whereas the X-trail diesel pump price of fuel plus 10,000k of road user charges was just under $1400. As far as I am concerned no contest, although the above does not include the higher registration charges or the generally higher servicing costs of the diesel. My current car is a Mitsubishi ASX diesel which a lot more economical than the X-trail ( Nissan claimed 8.0 l/100km, I got about 8.1/8.2, Mitsubishi claim 5.8 l/100km for the ASX, I am currently getting 6.1/6.2, but I have only done 6000km so it should improve as it gets more run-in). However new petrol engined cars are much more economical than they were even 5 years ago so the difference may be closed up more today. The local AA has been running a campaign for some time to restore the road tax on the pump price of diesel and drop the Road User Charges, so far without success as the large trucking companies and farmers prefer the present system and they have much more influence with the current politicians. Another proposed alternative is to remove the road tax from the pump price of petrol and apply the RUC to all vehicles, which is actually much fairer as the motorist is charged for their actual road usage instead of the running time of the engine,ie stuck in traffic with engine running but going nowhere.

AnalogKid
01-21-2014, 02:46 AM
My figures were pulled from distant memory the last time I tried working it out for the Land Rover. Maybe I was trying to figure out the equivalent cost of running a petrol V8. I can't remember and I've sold the Defender now anyway.

I'll give the matter more serious consideration when we come to change the Mazda6 wagon, likely for some kind of cross-over. Most of those only seem to achieve good economy in the diesel variants, but the rego fee is a little off-putting.

AnalogKid
01-21-2014, 03:47 AM
OK, I think I remember how I worked it out. Here's a quick spreadsheet with consumption rates in litres per 100 kilometres, with the price of that many litres of diesel and petrol and 100 km of RUC added in:



Litres / 100 Km
Diesel Fuel Price
Diesel + RUC
Petrol Fuel Price


10
15
20.3
21.5


9.5
14.25
19.55
20.425


9
13.5
18.8
19.35


8.5
12.75
18.05
18.275


8
12
17.3
17.2


7.5
11.25
16.55
16.125


7
10.5
15.8
15.05


6.5
9.75
15.05
13.975


6
9
14.3
12.9


5.5
8.25
13.55
11.825


5
7.5
12.8
10.75



Rates uses are RUC = $53 per 1000Km, Diesel = $1.50 / litre, Petrol = $2.15 / litre

At about 8.25 L/100Km, petrol becomes cheaper than diesel, that's about 28.5 MPG (US) or 18.25 MPG (Imperial).

This makes sense to me, but it's highly likely that there's a flaw in my logic here.

Nicholas Scheuer
01-21-2014, 07:02 AM
Good marriages and good dogs involve work, too.

Garret
01-21-2014, 08:01 AM
Good marriages and good dogs involve work, too.

True 'nuf

Nicholas Scheuer
01-21-2014, 08:27 AM
Wooden boats, too.

Garret
01-21-2014, 08:34 AM
Wooden boats, too.

Are you sure? I never have to do anything to mine - just plunk her in in the spring, sail her all summer, & haul her in the fall.

Damn, I just woke up. I was enjoying that dream! ;)

jonboy
01-21-2014, 01:42 PM
Here it used to be that diesel was 60% the price of petrol, but about two years ago the price started to creep up, and now the difference is maybe 10%...

today, 95 gas is about 1.60 a litre, diesel 1.45...BUT tax is the issue....when the price differential was so big, the annual road licence favored diesel cars too, my 2 litre petrol Subaru costs 140 a year my 240TD Merc costs 30 but now the tax system is based on cubic capacity and road tax will even out.

When the pump price evens up and the road tax stays relative to cc s, the only advantage with diesel for domestic cars will be longevity, ..the Merc has just passed 1600000 kms, about a million miles, the Subaru has 300000 kliks on the clock and is , well not exactly clapped, but won't make a mill for certain, and of course better fuel economy figures, generally about 25% better per similar engine size

Over in Spain, 150 kms away all the fuel is 30% cheaper than here, so the bottom line is the relative price of diesel versus gas is not production costs or cracking levels it's state tax revenue levies.