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Can Diesels Make It in America?

Diesel engines for passenger vehicles have been popular in Europe for a while, in part due to tax policies that encourage their use. At present diesels account for about half of passenger vehicles sold over there. In the U.S., however, the diesel share of the market registers in the low single digits.

One benefit of diesel engines is that they can deliver more miles per gallon. A downside is that diesel fuel tends to be dirtier, generating greater particulate emissions. This week, however, the EPA's new regulations requiring a dramatic reduction (97 percent) in the sulfur content of diesel fuel took effect. As the Washington Post reports today:

The change promises to significantly cut air pollution caused by diesel emissions. Regulators say high concentrations of sulfur in the old diesel fuel poison the engine systems that clean exhaust of harmful pollutants. The biggest concern is particulate matter, one of the byproducts of engine combustion, said Margo Oge, director of the EPA's office of transportation and air quality.
According to the story, automakers may respond by introducing more diesel models.
Detroit automakers have pledged to expand diesel offerings, particularly in pickup trucks. J.D. Power and Associates projects that the diesel share of light-vehicle sales is expected to increase to more than 10 percent by the middle of the next decade from 3.2 percent in 2005. Japanese automakers are also stepping up development of diesel technology.
It will be interesting to see how consumers respond, and gas prices may play a role. With gas prices having settled (at least for the moment), U.S. consumers may be less eager to give diesels another chance.

Evan H (mail) (www):
Having driven quite a few diesel cars and trucks in my life, I've always been surprised they weren't more popular. The Buick LeSabre diesel I drove in high school got nearly 30 mpg and it was as big as my first apartment. Of course it was dog slow and Americans tend to like cars that go fast. I don't want to turn this into a debate on the gas tax but if we paid EU type taxes the popularity of diesels would skyrocket.
10.19.2006 9:45am
McGuffin:
Your old Buick is very different from current common rail injected turbo diesels. State of the art diesels are not at all slow, noisy, smelly, or smokey. On the contrary, they can be the prime movers of some very high-performance vehicles:

Audi R10
Banks' D-Max Type-R
10.19.2006 11:15am
Don Miller (mail):
One of the problems I see for diesel vehicles, at least in my area, is that the state and federal government has so heavily taxed diesel that it is more expensive now than gasoline.

The argument is that Diesel is used by 18-wheel trucks and they do more road damage so they should pay more road taxes. That argument doesn't have any validity when the vehicle in discussion is a 3 cylinder smart car.

Consumers will compare fuel prices. They probably won't break out a calculator to figure out their per mile cost of diesel vs gasoline. They will see the higher price and opt to drive the vehicle with the lowest fuel costs.

Maybe the government will figure out a different taxing scheme for diesel that will solve this imbalance.
10.19.2006 11:20am
Houston Lawyer:
My understanding is that diesel is basically a by-product that is produced when producing gasoline. Consequently, if demand for diesel increases substantially, its cost will stay substantially above that of gasoline. Right now, it is $.40 per gallon higher than regular gasoline.

But it you can get 40 mpg with diesel in a car with pep, I'd consider it.
10.19.2006 11:30am
FantasiaWHT:
Don, you are forgetting that when standard gas prices were over $3.00, diesel prices were $.40 lower than standard gasoline.

Another point I'd like to make is that diesel engines can be easily modified to run on bio-diesel fuel
10.19.2006 12:04pm
Colin (mail):
Consumers will compare fuel prices. They probably won't break out a calculator to figure out their per mile cost of diesel vs gasoline. They will see the higher price and opt to drive the vehicle with the lowest fuel costs.

That's probably true, but it also seems like the sort of problem a good marketing agency could solve. It wouldn't be hard to advertise diesels by comparing per-mile costs.
10.19.2006 12:12pm
Chumund:
Diesels also achieve great synergies as hybrids, including very high mileage and relatively low emissions.

In fact, the Citroën C-Métisse Diesel Hybrid Sports Car, admittedly just a concept car, met Houston Lawyer's specifications: 42 MPG and 0-60 in 6.2 seconds with a top speed of 155 MPH.
10.19.2006 12:15pm
ak47pundit (www):
One problem with the new particulate standard is it will raise the price of diesel even further due to the higher refining costs. Now, the benefit of cleaner air may very well outweigh this but it is a consideration as cost of fuel will motivate buyers.

Diesel is still more expensive per gallon in Michigan than gas at the moment, due to higher demand for diesel worldwide.
10.19.2006 12:32pm
MnZ (mail):
Diesels also achieve great synergies as hybrids, including very high mileage and relatively low emissions.


Correct. The electric motor helps compensate for the diesel engines poor acceleration while the diesel engine can provide the batteries with more efficient electricity generation than gasoline engines.

In certain ways, diesel hybrids are much more promising that gasoline based hybrids.
10.19.2006 12:41pm
Chumund:
MnZ,

Indeed, and I think diesel hybrids are going to quickly become hugely popular in Europe. Making inroads in NA may take a little longer, but I think it will eventually happen--particularly if the United States gets more serious about biodiesel. And the good news in this scenario for the U.S. is that Europe will end up bearing a lot of the startup costs.
10.19.2006 12:54pm
Barry P. (mail):
A refiner's product slate is fairly rigidly defined by the design of his refinery. There is some amount of flexibility, but a refiner can't switch from, say, a 70-30 gas/diesel ratio to a 50-50 one. So, if diesel demand rose, then the price would rise or more diesel would have to be imported. Europe's refineries are configured from the start to produce more diesel.

Diesel used to have a good yield for the refiner, since it was cheap to make - gasoline requires a lot more manipulation and energy input - but the ultra low sulphur requirements will raise the cost of production.

Diesel makes sense for cars that do a lot of stop-start city driving: taxis, delivery trucks, and so on, as they use a lot less fuel at idle and low load conditions, but there is less of an advantage on the open highway.
10.19.2006 12:58pm
Jeff Shultz (mail):
Oddly enough, diesel used to be less expensive than gasoline. Significantly less expensive.

Then Volkswagen and Buick put diesel engines in cars.... Sometimes I don't really think it's "the market" that is setting the price. More like "the marketeer" is doing it.
10.19.2006 1:07pm
Colin (mail):
A refiner's product slate is fairly rigidly defined by the design of his refinery. There is some amount of flexibility, but a refiner can't switch from, say, a 70-30 gas/diesel ratio to a 50-50 one. So, if diesel demand rose, then the price would rise or more diesel would have to be imported. Europe's refineries are configured from the start to produce more diesel.

Is that always the case, or just with regards to gasoline/diesel? I was reading a case not long ago about a contract dispute between a refiner and a producer, in which the producer had proven that the refiner could easily have adjusted the ratio of products in order to make more high-value jet fuel and less low-value fuel oil. What's the difference?
10.19.2006 1:09pm
McGuffin:
The electric motor helps compensate for the diesel engines poor acceleration

Not really. Diesel engines do not have poor acceleration. They have much higher torque than gasoline engines, which is only partially offset by generally higher overall engine mass and reciprocating mass -- as well as by the need to accommodate the increased torque with a beefier (and typically heavier) drivetrain than is found in gasoline-powered cars. A diesel-powered car can be made to accelerate at a rate comparable to (if not better) than an equivalent gasoline-powered car. For example, the current model BMW 530i M Sport has a 2996cc gasoline engine. It does 0-62mph in 6.5 seconds (manual transmission.) The 535d M Sport, with a 2993cc diesel engine, does 0-62mph in the same 6.5 seconds. The 535d does this despite having about a 10% better fuel economy rating.
10.19.2006 1:10pm
McGuffin:
Diesel makes sense for cars that do a lot of stop-start city driving: taxis, delivery trucks, and so on, as they use a lot less fuel at idle and low load conditions, but there is less of an advantage on the open highway.

True, but somewhat misleading. Yes, diesels have very much lower fuel consumption at idle compared to gasoline-powered engines, but for the same reason diesels still have smaller but still significant advantages in highway cruising. In both cases, gasoline engines would be operating at part throttle -- essentially choking off the air supply to the engine, resulting in greatly increased pumping losses as the engine struggles to breathe. Diesels do not throttle the air supply, but rather leave the intake wide open and unrestricted; thus diesels have much lower pumping losses both at idle and at less than full-power relative to RPM settings. It is only when gasoline-powered engines approach wide open throttle that the diesel advantage is greatly reduced.
10.19.2006 1:23pm
Don Miller (mail):

FantasiaWHT:
Don, you are forgetting that when standard gas prices were over $3.00, diesel prices were $.40 lower than standard gasoline.

Another point I'd like to make is that diesel engines can be easily modified to run on bio-diesel fuel


In my state, when gasoline was $3.25, Diesel was $3.50 (examples). Diesel, even under the most recent price spikes never got under the price of gasoline.

Bio-diesel is a nice idea, for some people. There appear to be some economic problems with bio-diesel for large scale implementation. 1. Some bio-diesel is made from used cooking oils. This is cheap while these oils are free or of low-cost. However, demand creates price increases. Someone will figure out how to make money off of this process. The price will go up. 2. Current technology is a batch process. It doesn't adapt well to large scale production. Large here means output similiar to an oil refinery. There is research on continuous processing systems, but they are viable yet. 3. Some bio-diesel manufacturers are using virgin (unused) vegetable oils. This puts them in direct competition with the food industry. As more bio-diesel plants go online, vegetable oil prices will go up 4. I have been told that the energy return ration for turning plants into diesel is still a negative return. In otherwords, it takes more energy to produce than you can get out of it. Similiar to the ethanol problem. Smarter people than me are working on this though.
10.19.2006 1:27pm
McGuffin:
Ethanol does not have a negative energy return, and cellulosic ethanol is expected to have a substantial positive return.
10.19.2006 1:35pm
Chumund:
My understanding is that diesel engines produce their greatest efficiencies when running at a constant RPM and temperature, and I thought that actually makes them most efficient for long-distance highway driving (with the electric motors in a hybrid doing more work during short-distance and acceleration phases, where the temps and RPMs are changing).

Of course, it is not wrong to say that you can get gasoline engine dynamics from a comparable size diesel engine, particularly with turbos (and I gather diesels can handle higher compressions). But my impression is that you can really take advantage of hybrid technologies with diesels because of these other aspects, which actually means you can use smaller fuel engines (with lower peak horsepower but good low RPM performance), which means more weight that can be used by batteries, and so on.

Anyway, as I understand it, the Big Three have made diesel hybrids that were getting MPG efficiencies in the 70s and 80s, but the emissions were too high given the old fuel standards. With the new fuel standards, though, even if it makes diesel more expensive, MPG numbers like that would be very compelling--you don't need to be too quick with math to figure out that 70 MPG beats 35 MPG as long as diesel doesn't cost twice as much as gasoline.
10.19.2006 1:38pm
Don Miller (mail):

McGuffin:
Ethanol does not have a negative energy return, and cellulosic ethanol is expected to have a substantial positive return.


Maybe a better way to put it would be "The way the US currently produces Ethanol has a negative energy return". Mostly because we continue to insist on using corn as our feedstock. Sugarbeets would be much better. Cellulosic ethanol will be a major improvement and most likely will have a positive energy return. To the best of my knowledge, there are no large scale ethanol producers using this method. I have only heard about laboratory demonstrations. But it is promising.

I believe that long-term, bio-fuels like ethanol and bio-diesel, hold a lot of promise. I just find too many people aren't realistic about the current state of the technology and what kind of problems need to be overcome.

Some people blame big-oil for lack of progress. I blame inertia. The world energy market is huge. It will take a lot of work to move it in another direction. Beside, oil companies are smart. My bet is 50 years from now, we will continue to power our cars with fuels from Chevron, Texaco, Shell, etc. It may be ethanol, bio-diesel, hydrogen, or a petroleum product but these same companies will still produce and distribute it.
10.19.2006 1:57pm
Sigivald (mail):
Don: Around here (Oregon) road tractors pay less for diesel at the pumps than consumers do; they get tax exemptions on their fuel, and have to pay a weight/mile tax quarterly.

State taxes do vary, and in some localities diesel costs less than regular unleaded (here, it's less than premium but more than regular).

Biodiesel is, I agree, not useful as it is now. If it was ever seriously necessary, I hear the idea is to have vast floating algae-farms (and I suspect that once the output requirements were sufficient and it wasn't a boutique fuel for hippies, a constant-feed system could be worked out rather than using batches... it'd just make the physical plant larger. There's no obvious reason why you couldn't treat the fuel in a constant-feed system to remove the badness with glycerine, if you had enough demand to justify the investment...)

Colin: The difference is that gasoline and diesel are radically different fuels, while jet fuel and heating oil are basically the same base oil at different levels of purity.

(The link suggests that kerosene and diesel are different carbon chain lengths, but more accurately they're different ends of the same overlapping range. Certainly people who've done it report that diesel engines can burn anything from kerosene to home heating oil.)

Changing the percentage of output types from input oil is comparatively difficult and expensive, since it requires cracking hydrocarbon strands to different lengths. On the other hand, refining your fuel oil more so it's *purer* fuel oil suitable for use in jet engines, that doesn't require the same expense.

(Assuming you have enough of the smaller chain end of the fuel oil to convert to jet kerosene; if you need to crack the chains down, that gets more expensive.)
10.19.2006 1:58pm
McGuffin:
My understanding is that diesel engines produce their greatest efficiencies when running at a constant RPM and temperature, and I thought that actually makes them most efficient for long-distance highway driving (with the electric motors in a hybrid doing more work during short-distance and acceleration phases, where the temps and RPMs are changing).

That is also true for gasoline-powered engines. Both types of internal combustion engine are most efficient at a particular RPM and load condition. Hybrids (gasoline or diesel) work by choosing an internal combustion engine that is adequate to meet the average power requirement (and that is sized and designed to do so efficiently), using stored electric power to buffer the high load demands. Pumping losses in a gasoline engine at wide open throttle will be more comparable than partial throttle pumping losses to pumping losses in a diesel, but other losses at high load and high RPM will more than offset the pumping losses, so gasoline engines will operate most efficiently at a particular load, RPM, and partial throttle setting. Diesels do have some advantages over gasoline engines in the hybrid role, but electric motors are not required to compensate for inherent weaknesses in diesel engines' ability to accelerate vehicles -- diesels are at least as capable of accelerating non-hybrid vehicles as are gasoline engines. Diesels also have significant advantages over gasoline engines in partial power conditions, such as idling or highway cruising, and this accounts for much of their fuel efficiency advantage over gasoline engines.
10.19.2006 2:01pm
McGuffin:
Maybe a better way to put it would be "The way the US currently produces Ethanol has a negative energy return".

Nope, that's not any better in terms of accuracy. Research prepared by Argonne National Laboratory indicates a 38% gain in the overall energy input/output equation for the corn-to-ethanol process. That is, if 100 BTUs of energy is used to plant corn, harvest the crop, transport it, etc., 138 BTUs of energy is available in the fuel ethanol. That isn't enough to make ethanol cost competitive with gasoline, but it is still not correct to claim that even current ethanol production from corn results in a net loss of energy.
10.19.2006 2:05pm
Mike BUSL07 (mail) (www):
Can Diesels make it in America? Yeah... I own like 5 pairs right now. (Sorry).
10.19.2006 2:09pm
DanD (mail):
Knowing the coming change in emissions regulations for 2007 would result in some diesels being taken off the US market pending reenginering for ulra-low sulfur fuel and the new regulations, I snapped up a 2006 Volkswagen Jetta TDI.

It is reasonably fast, a bit less refined than the gasoline models, but very easy to live with. Mileage has never been below 42mpg, with a few tanks over 48mpg. Rural driving with less stop-and-go favors diesels, a hybrid like Prius or Civic does much better comparably in the urban/suburban grind; they lose that advantage on the open road, with less regenerative braking to recharge the electrics.

Diesel fuel prices are subject to effects from winter heating season and demand for home heating oil, competing for scarce refining capacity. Also, trucking demand fluctuations and taxation tends to push prices around, moreso than with gasoline.

Making new-generation diesels that meet the stricter emissions regs is tough, Volkswagen is out of the US market until 2008. Smaller engines are easier to clean up, but high-mileage passenger cars they would power compete with some fuel-efficient Civics, Corollas, and hybrids. Manufacturers are struggling to develop larger diesels that could power larger cars, crossovers, and SUV's. That is the marketplace's sweet spot, a lot of money to be made selling versatile, roomy, capable family and work vehicles making 24 to 30 miles per gallon.
10.19.2006 2:16pm
pallen:
Some questions:

1) Diesel gives more miles per unit-volume but is the energy density the same to begin with? I.e., how efficient is a diesel engine in extracting the energy content of the fuel relative to gasoline?
2) What's the relative efficiency of extracting diesel from crude? Does it require the same energy? Can you extract as much diesel from a barrel of crude as gasoline?
10.19.2006 2:17pm
JDS:
Please explain: "One benefit of diesel engines is that they can deliver more miles per gallon."

Aside from being able to go more miles on a similarly sized fuel tank, why is this an advantage? Do you care if your fuel tank is slightly larger?
10.19.2006 2:32pm
markm (mail):
There are at least 3 different technologies under "biodiesel":

1: Recycled deep-frying oil. Supplies are obviously limited, but to the extent used vegetable oil can replace petroleum it's a clear environmental plus. One problem is that cooking oil is formulated to minimize evaporation, which is the opposite of what you want when starting a diesel engine. It might also have a much higher freezing point than the petroleum fuel and block fuel lines or even freeze in the tank. I've heard that most of the issues with it are avoided by mixing 10% or less of cooking oil in with petroleum-based diesel fuel. If so, it seems like an opportunity for an oil company to collect restaurant waste and sell the mix at a pump, saving money as well as being 10% more environmentally friendly.

2. Virgin vegetable oils. I'm pretty sure these will be too expensive for the foreseeable future, that is more expensive than petroleum alternatives such as mining oil shales or coal to gasoline conversion.

3. Processes for converting garbage to oil. The developers of these processors claim that they'll break down almost anything of plant or animal origin into an oily fuel. Beyond that, I don't know. The advantages of getting fuel from the stuff that makes landfills smell are obvious, but I've got no idea of the processing cost, energy requirements, characteristics of the oil produced, or how the raw material supply compares to the potential demand.

#1 is a cinch, but limited in scope, #2 a pipe dream, #3 a question mark.
10.19.2006 2:46pm
Chumund:
McGuffin,

I think what I was trying to say--and please correct me if I am wrong about this--is that diesel engines obtain some of their highest relative efficiencies as compared to gasoline engines under extended highway driving conditions. That also happens to be when hybrids make the most use of the fuel engine part of their drive systems. Accordingly, there is a synergistic effect when it comes to diesel hybrids as compared to gasoline hybrids, because a hybrid vehicle specifically makes greater use of the fuel engine mostly when diesels have some of their highest relative efficiencies.

All of which is just supporting the point that diesel hybrids are a particularly promising technology from a fuel efficiency standpoint (relative to all of gasoline, diesels, and gasoline hybrids), and thus could be attractive for consumers even if low-emission diesel fuel sold at a considerable premium to gasoline.
10.19.2006 2:52pm
Colin (mail):
Sigivald,

Thanks.
10.19.2006 3:09pm
McGuffin:
Think of it this way, Chumund, (because I think it is simpler): Both gasoline and diesel engines operate most efficiently at some load condition (unique to each engine) that requires something less than the engine's maximum output; at such partial load conditions, gasoline engines pay a significant pumping loss penalty compared to diesels because of the gasoline engine's throttling of the intake air; the result is that diesels are even more efficient than gasoline engines when both are operating at their most efficient partial load conditions. On top of that, both gasoline and diesel engines that are sized for a vehicle's average power requirement can produce that average power more efficiently than can an engine capable of meeting the maximum power requirement that is forced to produce only the average required power. Actually, the "big engine" penalty for a diesel is typically smaller than for a max-power-capable gasoline engine (once again, diesels are more efficient than gasoline engines at partial power), but a diesel sized to meet average power needs will still be more efficient than the max-power diesel. The upshot is that you are correct that a diesel hybrid is typically more fuel efficient than a gasoline hybrid.
10.19.2006 3:10pm
JB:
Perhaps a stupid question: Wouldn't biogarbagediesel smell horrible? I ask because I have a friend whose car is modified to run on a high proportion of recycled deep-frying oil, and his car always smells like fries. The equivalent in garbage would be highly unpleasant.
10.19.2006 3:21pm
Fub:
Jonathan Adler wrote:
A downside is that diesel fuel tends to be dirtier, generating greater particulate emissions.
I know little or nothing of the current state of technologies to treat exhaust gas. In general I'm referring from everything from mufflers to catalytic converters to the myriad of industrial exhaust gas particulate "scrubbers".

From a naive viewpoint it seems that developing cost effective particulate matter scrubbing or filtration technologies might (not necessarily will) be overall more cost effective than focussing on chemical composition of fuels that apparently cause particulate formation.

Does anyone know the state of R&D in scrubbing particulates from exhaust gas, or whether this is even a major focus of current R&D?
10.19.2006 3:44pm
Chumund:
Thanks, McGuffin--that was an extremely helpful explanation.
10.19.2006 4:27pm
McGuffin:
From a naive viewpoint it seems that developing cost effective particulate matter scrubbing or filtration technologies might (not necessarily will) be overall more cost effective than focussing on chemical composition of fuels that apparently cause particulate formation.

They're not separable. Just as lead was removed from gasoline because that lead would poison catalytic converters, thereby rendering them incapable of scrubbing the exhaust, so too sulphur is being removed from diesel because it poisons the kinds of converters necessary to scrub diesel exhaust. Yes, lead and sulphur in exhaust pose dangers on their own, but the biggest reason for their removal from fuels is to allow various exhaust technologies to do their jobs in reducing other exhaust components. The sulphur on its own is not responsible for diesel particulate emissions, but its presence in diesel fuel prevents the use of technologies that will reduce diesel emissions.

Improved diesel emissions control technologies are a major focus of R&D now that the sulphur roadblock has been removed.
10.19.2006 4:52pm
Harry Eagar (mail):
'Changing the percentage of output types from input oil is comparatively difficult and expensive.'

Not so, according to my physics adviser, who formerly analyzed refinery practices for a big company. 'You just change the catalyst,' he says.

Refineries switch their proportions of gasoline/heating oil at least twice every year.

JB, if your friend's car smells like french fries, his biodiesel refiner is not running a good operation. I have a friend who runs several biodiesel refineries. He jokes that his car smells like a french fry, but I cannot smell it at all. (Some people claim to detect a faint odor.)

He tells me that biodiesel's biggest marketing problem right now is that there's a lot of crappy biodiesel out there because of poor quality control.
10.19.2006 9:11pm
christopher sullivan:
NY Times recently ran 2 interesting articles on diesel:

Honda Accord

Mercedes E320
The Mercedes E320 is just a tad out of my price range, but the Honda Accord diesel sounds too good too be true- 40+MPG & Honda reliability without paying through the nose for a hybrid battery that will need replacing at the 8-10 year mark. Honda says it'll be sold here within 3 years. Faster, please.
10.20.2006 12:58am
Lev:

2) What's the relative efficiency of extracting diesel from crude? Does it require the same energy? Can you extract as much diesel from a barrel of crude as gasoline?


It may seem a little goofy, but there is flash proram that illustrates basic petroleum processing, this site:

API Refining

this section:


How a Refinery Works
Explore the critical role refining plays in unleashing the potential of a barrel of crude oil and turning it into the specially formulated products that we rely on every day. These products include gasoline, agricultural chemicals, heating oil, plastics, and even prescription medicines. Demonstrated in this section are the sophisticated technologies involved in several key processes, including distilling, reforming, blending and treating that safely and efficiently help deliver energy in all its usable forms to American consumers.

Macromedia Flash Icon
Click here to view an interactive Flash HTML file



The answer to your questions is, it depends on the crude oil being fed to the refinery, and the flexibility and efficiency of the refinery itself. Crude oils range from relatively low viscosity and relatively sulfur and metal free, to very viscous and heavily contaminated with sulfur and metals. Some refineries were originally designed to process relatively clean and low viscosity crudes. More recent refineries have been designed or upgraded so they can hand the good stuff, as well as the crappy stuff.

You can get an idea of the difference in quality and thus in the difficulty and expense of processing by comparing the market prices of West Texas Intermediate, Brent Crude, Saudi light, to californian and venezuelan crudes. The former are relatively lower viscosity, sulfur, metals than the latter.
10.20.2006 3:23am
Lev:
10.20.2006 3:28am
dweeb:
Some bio-diesel manufacturers are using virgin (unused) vegetable oils. This puts them in direct competition with the food industry. As more bio-diesel plants go online, vegetable oil prices will go up

Michael Bloomberg's got that angle covered - he's going to outlaw deep fried foods so all the production can go to bio-diesel applications.
10.20.2006 5:55pm
dweeb:
Don, you are forgetting that when standard gas prices were over $3.00, diesel prices were $.40 lower than standard gasoline.

Not where I live - they've been consistently higher. The reason is simple economics.The majority of the diesel market is COMMERCIAL transportation, where the fuel demand is far less elastic - the trucks and busses have to run. In Europe, it's a different story - not only is diesel demand from commercial vehicles more elastic, but when truckers there don't like the price, they strike by parking their trucks in the middle of the road and shut down everything. There's also the problem that diesel uses the same petroleum components as heating oil, and again, the demand isn't as elastic as gasoline - you can decide not to drive across four states for a vacation, but in the North, heating the house in winter isn't optional
10.20.2006 5:56pm
Mike Brown (mail) (www):
Here in central NY, the price of Diesel has tended, over the three years I've owned a VW Jetta Diesel, to be around the same as (or slightly less than) mid-grade gasoline during the summer, and around the same as (or slightly higher than) premium during the winter.

I consistently get 48-50mpg in everyday commuting, and 55mpg on the highway. I got around 30mpg I got on my last car (which was pretty good in itself), so I'm paying about 10% more for fuel to get nearly twice the mileage - even at more than premium gas prices there are significant savings.

As for power, comparing the 0-60 times of Diesel vs. gasoline cars is misleading. Watch some of the tests on Motortrend or the like, and you see that they test 0-60 times by revving the devil out of the engine (to get into the high RPM range where gasoline engines develop maximum power) and popping the clutch with tires smoking - how often in ordinary driving do you simulate drag race conditions? Diesel engines have all of their power (torque) in the low end, which means that it's usable as you accelerate under ordinary conditions. If you drive one for a while, you wouldn't go back.
10.23.2006 5:48pm