The Dirty Truth About 'Clean Diesel'
nytimes.com
nytimes.com
The problems are ships (which burn stuff that's essentially waste and generally have no form of emissions treatments [1]), locomotives (these burn diesel, but again, the vast fleet of old diesel locos doesn't carry any adequate filters [2]), wood furnaces (in poor countries, where anything that burns is used to heat and cook [3]), and factories where no money is available to get their emissions under control ([3]).
Also, to clarify, I'm not after greenhouse gases, but after the stuff that actually kills people. Greenhouse emissions are nasty but as others have noted, agriculture is to blame here and not cars or anything else.
[0]: http://www.gizmag.com/shipping-pollution/11526/
[1]: see https://en.wikipedia.org/wiki/Fuel_oil#Environmental_issues
[2]: http://www.russfrei-fuers-klima.de/themen/schienenverkehr/ (german unfortunately)
[3]: https://en.wikipedia.org/wiki/2013_Eastern_China_smog#Causes (though I have to admit, it's coal, not wood, but the result is the same)
"Recently, officials in Milan temporarily barred cars from the city; in Rome, too, persistent smog has forced the authorities to limit the use of private vehicles. Back in March, Paris was enveloped in a gray cloud of choking fumes that obscured the Eiffel Tower for hours and briefly earned the French capital the title of the world’s most polluted city, beating out even Beijing. An air quality expert in Britain reported that much of it was “stale diesel” from traffic emissions generated in European cities."
Everyone and his mother focuses on cars. Even a 50% reduction on new cars will take DECADES until a meaningful impact on the total car emissions! Old cars get resold to Africa or other poorer continents, so the impact of new cars is next to zero!
Meanwhile, the container, cruise and other heavy ship industry belches emissions on multiple orders of magnitude than these savings. Fix fifteen fucking ships and you save in a single year more pollutants than you could save in a decade by stripping 10% of worldwide car emissions.
However, car emission testing programs already exist which force the driver to do repairs to their existing car.
Pollution deaths are still mostly a local/regional problem, so fixing ship emissions is a problem for port cities, while fixing car emissions is a problem for everyone who lives near a major road.
> However, car emission testing programs already exist which force the driver to do repairs to their existing car.
Repairs, yes. But repairs only set the car back to whatever standard applied when it got introduced. Retrofitting is theoretically possible, but at a huge expense to the car owner. And tbh I rather see huge shipping co.s having to pay for upgrading their ships than the often poor people stuck owning a beat-up car.
> while fixing car emissions is a problem for everyone who lives near a major road.
Problem is that the only real fix is diverting the traffic or eliminating it altogether. Due to the high percentage of old cars on the road new emissions standards are useless for immediate fixes.
http://www3.epa.gov/climatechange/ghgemissions/sources/agric...
I also wonder about humans vs agriculture for gas emissions. What's worse?
Kraków in Poland is ranked as one of the worst cities in Europe in terms of air quality with these pellets as a leading cause.
Source: http://www.krakowpost.com/6285/2015/11/krakows-air-quality-a...
If so, whatever is true of wood stoves is true of them, as far as carbon neutrality. It's the same resource. I guess burning wood is 'carbon neutral'? I guess, unlike fossil fuels, it is 'sustainable', in the sense that more can be grown?
It can still be awfully polluting. I think most modern pellet burning stoves actually emit less pollution than burning straight wood, because they burn more efficiently. But 'less' does not mean 'not'.
Only if you grow a unit of mass of wood at the same rate at which you burn it. Otherwise the stove actively transfers carbon from forests to atmosphere.
(was: citation needed)
https://news.ycombinator.com/item?id=10716102
"15 Biggest Ships Create More Pollution Than All Cars in the World (2013)"
Indeed, but no matter how you look at the data (and where), stuff like banning cars from roads is a placebo measure, given the slow share of cars in said pollutants.
The most problematic point, very often overlooked, is that factory chimneys (and, to a lesser degree, ship chimneys) belch their smoke in higher air, which means that the pollutants in the smoke can fly for hundreds of kilometers before coming down on the earth and causing problems.
Also, the entire purpose of a chimney is to spread the emissions over a larger area...
> the dispersion of pollutants at higher altitudes can reduce their impact on the immediate surroundings. In the case of chemically aggressive output, a sufficiently tall chimney can allow for partial or complete self-neutralization of airborne chemicals before they reach ground level. The dispersion of pollutants over a greater area can reduce their concentrations and facilitate compliance with regulatory limits. [0]
It is certainly true that stack emissions can have a significant health impact (for example coal power stations in China). But there are also places where the effect is less significant as the ambient level is considered to be safe. Vehicle emissions can cause local levels to be much higher.
I agree that certain sources are popularly ignored, but that is not a reason to also ignore vehicle emissions.
The problem is: vehicles have a freaking high life time if they're not destroyed in accidents. Even if all new cars by tomorrow were electric, it'd take years for these new cars to replace the old cars (and thus solving the problem of local pollution).
To make stuff worse, old cars are usually exported to Africa (http://www.zeit.de/auto/2010-01/auto-export-afrika) where they basically run until they cannot be patched up any more and of course, once e.g. a soot filter breaks down in Africa, no one will replace it.
All this "uuh our vehicles must be cleaner" is just bla bla of the industry to sell more new (and, because of more complex technology, more expensive!) cars. The actual impact of these measures is next to zero because of a car's afterlife in Africa or wherever.
Mandating proper emission filtering on all factories around a city helps immediately, mandating stricter emissions on new cars does nothing at all.
But the wierd thing is that in terms of cargo tons carried, the larger ships pollute less only because the marginal cost of fuel of carrying another container is lower than the marginal cost of adding another ship.
So the crappy polluting ships are having an unknown effect on the oceans but having less and less of an effect as more and more cargo is carried by fewer and fewer ships.
Clean diesel can be very clean. Clean gasoline engines are something we created in the 70's, 80's, and 90's; We used to have an enormous smog problem from tailpipe emissions, but we've basically solved it through regulation of what sort of fuel gets made and what sort of emissions controls are built into cars. With diesel trucks, we resolutely refused to make the corresponding changes for several decades; It's going to take 20+ years to get the truck fleet on the same footing as cars, and we only started the ULSD rollout about 10 years ago; we've only just begun major emissions level requirements in 2015 vehicles. The trucks you and I grew up around have no attempt to control emissions whatsoever, due to the power of US industry lobbyists. There is very little comparison to the clean diesels that are now a well-developed, highly regulated chunk of the EU passenger car market.
The diesel emissions scandal was about a deliberate conspiracy within one manufacturer, wherein software was written to turn off major emissions controls in order to gain a very small mileage advantage, and then turn them back on to pass emissions testing. It has no relevance whatsoever to the practicality of clean diesel engines.
"An air quality expert in Britain reported that much of it was “stale diesel” from traffic emissions generated in European cities."
how much is "much of it" ?
and big on personal observation like
"As anybody who has seen the black smoke spewing out of the pipes of a big rig as it changes gears can testify, diesel has a fatal flaw."
IMO a fluff piece.
If the effect was immediate and those 9000 odd people just dropped to the ground dead as you drive past them, we would see a more direct reaction.
> In other words, a driver who steps on the accelerator of a diesel car may be filling the lungs of nearby pedestrians, cyclists, infants in strollers and other drivers with potentially deadly particulate matter.
Driving a diesel car is nothing like driving a gasoline car. In a gasoline car, when you "step on the accelerator" you follow the horsepower curve, revving the engine to 5000-5500 (perhaps higher) RPMs before shifting. This is because the torque curve in a typical gasoline vehicle follows the horsepower curve until you get close to the red line, typically 6500-7000 in modern cars.
In a diesel passenger car (using a VW TDI as a reference) the torque develops early, peaking at about 2000-3000 RPM, then falls as you go past 3000. So if you want to get going fast in a TDI, you keep the shifting going on at around 3000. With the way the DSG and ECU work in a TDI, that means running at about 1/3-1/2 throttle. Definitely not "stepping on it". Also note the red line on a TDI is 5000 RPM.
As a side note, the TDI ECU's algorithm for detecting faulty inputs imposes about a 1.5 second delay on actually opening the throttle if you floor it from a dead stop. It's very counterintuitive if you need quick acceleration, you have to give about 1/4 throttle, then slowly increase as the car starts moving. Again, if you want to go fast, the car actually incentivizes NOT stepping on it.
Second, and this is the one that everyone seems to fail to notice. The TDI passes emissions when the bypass mode is disabled, putting the ECU into normal mode. What normal mode means is the car more frequently cycles the Diesel Particulate Filter (DPF), which reduces NOx emissions by accumulating soot in the DPF then burning it by passing unburned fuel through the engine 1 out of every 4 cycles while the system is in a DPF cycle. The unspent fuel lands on the soot, then the heat from the following combustion cycle ignites it and dumps mostly ash/greatly reduced NOx down the tailpipe. There are of course performance and fuel efficiency issues with normal mode. With proper tuning of the software it should be able to both meet emissions standards without sacrificing too much in the drivability department. A decrease in mileage is inevitable though.
VWs mistake in all this was failing to accept a 28/38 MPG (or 27/37) rating, and insisting on 30/40 MPG (which likely came at the behest of VW Marketing). Had they been willing to accept slightly lower MPG numbers, they would have been in compliance with the law.
To me, all the kerfuffle seems a little overblown. I don't give VW a free pass for breaking the law, they need to be held accountable. But this whole idea that diesel is doomed seems very off kilter to me. Diesel produces fewer greenhouse gases, converts hydrocarbons to kinetic energy most efficiently of all internal combustion engines, has fewer emissions from ancillary chemicals than gasoline like acetone and toluene (both unregulated at present). It truly is the way forward until we can retool the worldwide vehicle fleet to be driven by electricity (30 years minimum if we start right now).
When I look at this anti-diesel campaign, I look at it through the lens of the Saudi's fear not of peak oil, but of peak demand. Diesel threatens to lower the plateau of peak demand. http://www.bloomberg.com/news/articles/2015-04-12/saudi-arab...
Doesn't an LPG ICE convert the chemical energy in the hydrocarbon fuel more efficiently (although there is less embodied energy per unit mass of LPG as compared to diesel fuel)?
It does that because the laws of physics require it. Diesel is not exempt from the laws of physics: horsepower = torque * rpm. This is not an approximation, it's an exact relationship, diesel works identically.
You can put different gearing on diesel or gasoline to make them work however you like - the only thing that matters at the end of the day is horsepower, once you know the horsepower torque and rpm can be traded off against each other.
> Had they been willing to accept slightly lower MPG numbers, they would have been in compliance with the law.
If it were so simple to just change the programming VW would have released a fix already for their illegal cars. But they have not because what they are trying to do (clean diesel) actually appears impossible. It's not the simple MPG change you are trying to make it out to be.
> But this whole idea that diesel is doomed seems very off kilter to me. Diesel produces fewer greenhouse gases, converts hydrocarbons to kinetic energy most efficiently of all internal combustion engines, has fewer emissions from ancillary chemicals than gasoline like acetone and toluene (both unregulated at present).
Now it's you that is trying to mislead people.
They are only efficient if allowed to pollute! If you restrict them from polluting they are NOT more efficient than gasoline. (Which you touched on just one paragraph before, and then seemed to immediately forget.)
You simply can't have it both ways, and making clean gasoline is much easier than clean diesel.
> has fewer emissions from ancillary chemicals than gasoline like acetone and toluene
Maybe less of those, but far more of much much more harmful stuff. Both of those have very short lives in the atmosphere and cause very few problems. Acetone is actually pretty much non-toxic, it's made naturally in the body. And Toluene is only mildly toxic - I'll take both over what diesel produces.
Gasoline Engine: http://paultan.org/images.paultan.org/uploads/2006/08/a4test...
Diesel Engine: http://g35driver.com/forums/attachments/g35-sedan-v36-2007-0...
> They are only efficient if allowed to pollute! [Citation Needed]
Industry mags are predicting the MPGs will meet the EPA Window Sticker and the emissions requirements.
http://www.edmunds.com/car-news/how-the-volkswagen-diesel-sc... https://www.cars.com/articles/vw-diesel-owners-should-get-ep...
Wired's informal testing shows less than a 10% decrease in fuel efficiency when tricking the ECU into going into "test" (and therefore NOx-compliant) mode:
http://www.wired.com/2015/10/vw-diesel-cheat-mode-mpg-perfor...
Of course, the actual results remain to be seen.
You might want to check out the tdiclub.com forums, there are some top techs on there that explain what is really going on.
There seems to be a common misconception about CO2 emissions from cars, evidenced in this statement.
Burning hydrocarbons produces CO2 and water. The more burned, the more emitted. The efficiency of the engine (and vehicle in total) determines how much fuel is used while driving. More efficient = less emissions.
Diesel engines are thermodynamically more efficient by virtue of their higher combustion temperature and pressure. It's this same high temp and pressure that causes nitrous and sulphur oxide pollutants to form in the exhaust gas. Hence there is a definite trade-off between high thermodynamic efficiency, and NOx pollution.
Diesels are more efficient, but less clean.
Sure, there is an indirect health problem with pollution, but there is also a much more direct health problem: cars causing fatal accidents. The best way is hence to fix the problem at the root: personal cars do not belong in cities, and cars do not belong in pedestrian areas.
I'd be happier to fix both problems at once, but fixing just one would go a long way.
There is no healthy threshold for particulate concentration and other pollution, even if safety standards want to create this illusion. It's a continuous world, after all.
Deaths in all road user groups is about 2,000 per year in the UK. https://www.gov.uk/government/publications/annual-road-fatal...
Estimates for deaths caused by air pollution are usually stated as being about 30,000 per year, but that number could be much higher. http://www.theguardian.com/environment/2015/apr/02/air-pollu...
Yes, air pollution presumably causes a bunch of premature deaths, but clearly air pollution can not directly kill you. In the meantime, road traffic accidents is one, if not the biggest factor in the death of otherwise totally healthy people like teenagers, who we would easily expect to live another 40 years.
In any case, the magnitude of the problem doesn't exactly matter, as banning diesel cars doesn't solve the pollution deaths. Normal gasoline cars have the same pollution problems, if only on a somewhat lesser scale, particularly when used for short distances as customary in the city.
As such, yes, we still have to get rid of cars in cities to fix this.
People die from pollution induced asthma attack. That's pretty direct.
That's not in the slightest true. A well running gasoline car produces so few pollutants that some actually produce exhaust that is cleaner than the air that entered it.
No diesel can claim that.