Compressed Natural Gas

January 18, 2001 6:52 AM

Compressed Natural Gas is much more cleaner than diesel, the dual-fuel engines run quieter and you get lower operating costs. It's certainly very promising, and the technology is already widely implemented from busses to vans to trucks. However, changing a truck to this system can be costly, especially for small fleets. With this and the lack of fueling stations across the nation, do you still think this might be a good option for the future?
posted by tiaka (28 comments total)

Presently, there are certain groups (namely those who maintain fleets that run locally, and don't have the need to haul lots of stuff) that work well with CNG. The Sisters of St. Joseph here in town have their own fleet of CNG cars, and from talking to them, are really quite pleased with the results. Since they have their own refueling station, the only real drawback is the the larger CNG tank cuts trunk space in half. But, given their ecological stance, it is a small price to pay.
posted by Avogadro at 7:05 AM on January 18, 2001

LPG (liquid petroleum gas) is much better than CNG. CNG generally requires a lot more work is done to the vehicle, and more space is required. This is okay in large vans but not in cars and such.

LPG is taking off (slowly) in the UK. There are now over 600 LPG filling stations across the country, and LPG is half the price of gasoline. The government will even pay up to 60% of the LPG conversion costs if your car is under a year old and listed in a special database of theirs. The beauty is that you have both an LPG tank and a gasoline tank, so the range of your car is much increased.
posted by wackybrit at 7:39 AM on January 18, 2001

Personally I think alternative fuel solutions for vehicles are a great idea. Unfortunately since Bush is intent on allowing for more oil exploration (and Norton agrees) I have this gnawing feeling that he won't be so quick to push for such efforts.

I'm more in favor of the hybrid gas/electric cars although I think Ethanol is a much cleaner solution.

The DOE has a great page to "map out" refueling stations for various forms of alternative fuel.
posted by bkdelong at 8:52 AM on January 18, 2001

gas/electric hybrid cars are kind of cool, but natural gas? Please. Petroleum and natural gas are not renewable energy sources. Hemp is the answer, guys.
posted by snakey at 8:59 AM on January 18, 2001

Ack. Bad link. Here's the good Hemp Fuel Link
posted by snakey at 9:02 AM on January 18, 2001

Well, more oil is something that's needed at this point, so, it does make sense, especially when diesel is running at 1.70-2.40 a gallon in Jersey. About a year ago we had diesel up at 90-1.10 or so. I feel that the fuel deal is mostly to get the economy more stable, fuel prices down, it reduces the transportation costs of freight and products. People see fuel prices going down, they'll feel more secure. More spending. Although, chances are there is some influence from the outside parties.

As I've read that Clinton didn't really explore alternative fuel industry either. I hope Bush would be wise enough. But then again, most of Washington looks at all this stuff like it's mumbojumbo from the voodoo doctor.
posted by tiaka at 9:30 AM on January 18, 2001

Has anyone done a back of envelope study on how much Hemp would be needed to fuel American cars.
posted by stbalbach at 9:51 AM on January 18, 2001

Can you say 'biodiesel'? No link; sorry; Lynx on a VT102 again, but do a search; you'll find that, between oil palms, and used cooking grease, you can run a *lot* of cars. Particularly, search for the delightfully named "NOPEC".
posted by baylink at 10:10 AM on January 18, 2001

Wackybrit - what's the difference between liquid petroleum gas and gasoline? Is LPG cleaner? More efficient? I've never heard of the stuff before, but hey...the more alternate ideas for fuel, the better.

The MTA has been slowly switching its bus fleet over to CNG, though I think they're still using diesel buses in the Valley and the Eastside. Better to get the buses up to snuff than digging holes in the ground for our Go-Nowhere subway...
posted by RakDaddy at 10:13 AM on January 18, 2001

I've seen a company that apparently modifies current gasoline engines to burn alternative fuels and gasoline concurrently. Supposedly the addition of a small amount of alternative gaseous fuel (like propane) into the piston chamber improves the combustion of the gasoline to the point that emissions are removed almost completely. Also, they claim an increase in engine performance, etc etc. You attach the gaseous fuel line directly to the intake manifold, so no complicated pressure sensing computer needed. Supposedly easily reversible, if you run out of gaseous fuel the engine reverts back to gasoline only, etc etc. Sound interesting, haven't been able to find an independent review of it anywhere.
Welsch Technologies.
Any thoughts?
posted by evad at 10:23 AM on January 18, 2001

LPG is propane. LPG stands for "Liquified Propane Gas". Because propane is a gas at normal temperatures, it mixes more evenly with the air in the cylinder and burns better. It's also got a lower proportion of carbon than gasoline, which also makes it burn cleaner. Propane is C3. Gasoline is a mix of C6, C7 and C8. (Both are hydrocarbons; fill all the spare links with hydrogen.) However, that means that propane has less energy per kilo because the majority of the energy in hydrocarbons is in the carbon.

LPG is also very cold (comparable to liquid nitrogen), and it takes a different kind of tank to store it (essentially a metallic Thermos bottle). It's under pressure in that tank, too; it will boil a little until it reaches its vapor pressure. When you open the tank, it's going to blow out flammable gaseous propane at you. You better not be smoking because if you are there will be an explosion. There will be no "self-serve" LPG refilling stations, and the people who do it will be trained first.

LPG works better for professionally maintained vehicles; it's a bit too unforgiving for Joe Sixpack or Jane Housewife, let alone Tommie Teenager.

On a Nova episode I saw a great demonstration done by the late Gene Shoemaker. The show was about the use of hydrogen as a possible fuel, and it was dealing with the impact of the Hindenberg explosion on people's perception of hydrogen as a fuel. Everyone has seen that newsreel of the Hindenberg burning, and most people think that Hydrogen is horribly flammable. What he did was to go out into a rocky area and set up in turn three cannisters. Then, from a long ways away he used a rifle and shot a hole in each cannister. The first contained gasoline, and it started burning. The second contained LPG, and it exploded. There was no sign of the cannister left afterwards. The third contained hydrogen, and it didn't even catch on fire. The point was to demonstrate that hydrogen was safer than anything we use now. But it also demonstrated just how dangerous LPG is.

I wouldn't want to be in a major car wreck where any of the cars was powered by LPG. I don't think it will ever become a significant fuel for private vehicles.
posted by Steven Den Beste at 10:49 AM on January 18, 2001

Biomass fuel is an interesting issue. Brazil has lead the way on this, oddly enough. Sugar is a major crop in Brazil, and it happens that there's a lot in sugar cane which isn't useful. Traditionally the left over cane was just burned once the sugar syrup had been pressed out of it, although a lot of it was burned in furnaces to provide power for the sugar mill. But now Brazil is using it to produce methanol for fuel. What they do is mix it with gasoline (the way ethanol is sometimes here in the US) so as to reduce imports of petroleum.

Hemp is not a very good choice, however; if what you want is something which grows really fast and produces biomass much faster and more per acre, there are several other plants which are better for it.

Corn would be much better. The US does grow a lot of corn, but the majority of it is used for animal feed, and they grind up the entire plant for that rather than just using the grain. (Before feeding it to animals, however, they let it get moldy. It's known as "silage". By doing that, a lot of the cellulose in the plant is broken down into less complex sugars, and becomes useful to the animals instead of simply being fiber which passes through undigested. Cattle and particularly hogs think it's delicious and will snarf it right down.)

Another thing which would be better is bamboo, in climates where it will grow. There are certain grasses which are better, too. Hemp is really a poor choice by comparison.
posted by Steven Den Beste at 11:05 AM on January 18, 2001

I too am for "alternative" ideas for fuel in the future, but not the way we did it here in Arizona! Our state passed a bill (the Alternative Fuel Bill), which allowed consumers to convert their vehicle to Compressed Natural Gas (CNG) or Propane. It entailed adding a converter section to the engine compartment and a tank for holding the fuel. This bill also gave tax credits towards the purchase of a NEW vehicle, at a percentage of the cost of the vehicle or $20,000 max. Guess what everyone did? They all went out and purchased Tahoes, Suburbans, Escalades and any other large SUV they could get their hands on. In fact, nearly 95% of the "new purchases" were vehicles of this kind. Not to mention, there was not stipulation that the vehicles even had to use the alternative fuel at all. So a bunch of people screwed the state for a new vehicle, costing us nearly $600,000.00.....OUCH!
posted by 120degrees at 11:31 AM on January 18, 2001

Steven: There are several Hydrogen powered buses here in Chicago. I recall when the first went into operation, the mayor drank a glass of waste water that came out of the tailpipe to demonstrate how clean the vehicle is. They are kind of neat to see drive by, they spout pretty, clean, white vapor that you don't have to feel bad about. I don't think it is a hybrid vehicle, I believe it is 100% hydrogen powered.
posted by thirteen at 11:32 AM on January 18, 2001

Oops! Earlier post should read $600,000,000.00 (six-hundred MILLION)....not $600,000.00
posted by 120degrees at 11:32 AM on January 18, 2001

Steven Dan Beste, I would disagree with your conclusions on hemp. As the
link states, hemp produces more seed oil than current oilseed crops. But I emphatically disagree on the issue of how fast hemp grows. In the US, it would be possible to harvest hemp 2-3 times per year. As for climate, hemp grows in nearly any climate, and it can be grown even in poor soil where corn won't grow. That's one reason why Poplular Mechanics called it the 'billion dollar crop'.
posted by snakey at 11:40 AM on January 18, 2001

Hyperlink about Chicago's hydrogen powered buses.
posted by thirteen at 11:44 AM on January 18, 2001

Steven? Do you actually know anything about LPG fuel? Perhaps we're talking about different types of LPG here.. but LPG is already mildly popular in the UK, and yes.. the garages are self serve! LPG is simply a pressurised liquid gas. Anyway, whatever you mean by there never being any self serve stations is wrong.. there are over 600 in the UK already!

The danger in a crash situation is minimal.. the tanks are designed to slowly release the LPG in the event of a crash or tank breach. This is to eliminate the risk of the tank exploding.

This page has more information about LPG including the environmental benefits compared to gasoline.
posted by wackybrit at 12:38 PM on January 18, 2001

Snakey, the point of biomass is not to create oil. The point of biomass is to convert the cellulose to methanol. The goal is truly mass; you want to produce as many tons per acre as you possibly can, and the percentage of it which is oil is unimportant. Hemp is a lousy choice for producing as much mass as possible.

No oil crop produces even a small fraction of the energy which is present in the cellulose and other non-oil materials in the plant. Why waste all that? Anyway, methanol is an excellent fuel. It's what a lot of race cars use.

Wacky Brit: I'm not concerned about the tank exploding. I'm concerned about the propane exploding. The problem is that it creates an explosive mixture with air, much more so than gasoline does. No matter how it's released, if the release is fast enough (and it doesn't take much) then a sufficiently rich mixture can be created which will explode given any spark or flame source. And while the tank can be made crash-resistent, it can't be made crash-proof. Unless it's made of armor plate, it's always going to possible to breach the tank in a sufficiently violent crash. 110 KPH (70 MPH) in a car represents more than enough kinetic energy to break anything which isn't prohibitively heavy or ridiculously expensive (e.g. titanium). I routinely drive 135 KPH (85 MPH) for much of the trip when I go to Vegas. That's the prevailing speed of traffic. Remember that kinetic energy goes up as the square of the velocity.

I fully understand the environmental impact of LPG. I also understand the risks, as apparently you don't. I'm not impressed by that web page; it's a flack sheet put out by the company pushing the product. I'd prefer to see a testimonial by a test agency which has no vested interest. In the US, I'd want to see testing by Consumer Union, or United Labs, or National Institute of Standards and Testing. I'm sure equivalent agencies exist in the UK. Them I'd believe.

I don't think LPG is safe for consumer use, in which case the environmental aspects of it are unimportant. For truck/bus/fleet use, that's a different matter.

posted by Steven Den Beste at 1:51 PM on January 18, 2001

[off topic]
"I routinely drive 135 KPH (85 MPH) for much of the trip when I go to Vegas."

So YOU'RE the guy slowing everyone down to 85? Stop doing that!
posted by y6y6y6 at 2:08 PM on January 18, 2001

Thank you Steven! I remember seeing that Nova episode once in High School, and I was so convinced that we would have hydrogen cars in just a few years. Unfortunately, the teacher edited the tape, so I never realized it was on Nova. Hmn, I wonder if they have any archives at their website.....
posted by eckeric at 2:31 PM on January 18, 2001

I just remembered that the rifle demonstration wasn't done by Gene Shoemaker. He did a different demonstration in another show with a rifle. I have them confused. (I guess I've been watching too much morally uplifting documentaries. Gotta start watching more "Simpsons" or something.)
posted by Steven Den Beste at 2:56 PM on January 18, 2001

I called up the Welsch guy, he seemed really nice. I thought it would be fun to convert one of the trucks to his system. He should get back to me with a quote tomorrow.
posted by tiaka at 3:01 PM on January 18, 2001

Well, whatever you're smoking I'd like some. The British government is actively encouraging the use of LPG. Infact, LPG units have passed all British Standards test and received the British Kitemark (that's the independent standard you're calling for). The British government will even pay up to 70% of the costs to get it converted.

LPG is safe for consumer use, with nearly a thousand garages offering it self-serve. All of this equipment has to have been, once again, approved by the British Standards agency.

So.. car insurers don't mind LPG (no higher premiums), the UK government is encouraging its use, you can get it self-serve, and its been approved by British Standards.

Of course, this doesn't mean it's 100% safe. Petrol isn't 100% safe either, but it means it has to have passed -some- safety checks. LPG is also very popular in Japan where it is used by the public.

I don't know if you're anti-anything-new (I guess the whole of the US is like 2 years behind in cellular phone technology) over there.. but we have to try new things.. and so far, LPG is totally safe.
posted by wackybrit at 6:54 AM on January 19, 2001

car insurers don't mind LPG
Until an LPG cars goes boom, then watch the premiums go up.
the UK government is encouraging its use
As they did with animal feeds containing BSE infected materials, as they are with genetically engineered crops....sorry, encouragement from the government doesn't give me comfort in the safety of anything. I like facts.

I've been seriously considering LPG as an alternative recently, but Steven's post brings the thought of being trapped inside a car filling with escaping gas to mind. Petrol fumes are one thing, but a gas/air mixture in an enclosed space....I dunno.
I don't know enough about LPG's safety aspects to make a descision yet, all the information comes from retailers and producers and despite the Kitemark, I don't like the thought of being rear-ended with a pressurised gas cannister in the boot.
posted by Markb at 7:17 AM on January 19, 2001

The US is "two years behind" in cellular phone technology because we don't have to pay by the minute for local phone calls. In much of Europe, wireless phones are actually less expensive than land lines, and more convenient to boot, so naturally people have adopted them with enthusiasm.

Cell phones here are getting down in price, but you're still paying a premium for convenience. Hard to compete with free local calls and 5-cent-per-minute long distance.
posted by kindall at 8:01 AM on January 19, 2001

I don't know if you're anti-anything-new (I guess the whole of the US is like 2 years behind in cellular phone technology) over there.. but we have to try new things.. and so far, LPG is totally safe.

This is off-topic, and I apologise, but I never really understood why someone would punctuate their argument with baiting, especially baiting all the residents of a country (not mine, incidently) which makes up the bulk of members on the board you're debating on.

Your points of fact should be (and in this case they are) enough to carry your argument and at the very least make people question their initial biases. Why ruin a good argument with a completely irrelevant point?

I've never heard of LPG, and through Steven's skepticism and questioning and your fact-finding and debate points I've learned a reasonable amount about it. Enough to get me curious, at least, which is why you pointed it out, no?
posted by cCranium at 8:16 AM on January 19, 2001

I don't think LPG is safe for consumer use, in which case the environmental aspects of it are unimportant. For truck/bus/fleet use, that's a different matter./bus/fleet use, that's a different matter.

I have to agree with this: and really wish that ol' Gordon had offered the fuel protesters a tax write-off against the cost of converting. Though I'm sure that every driver in Britain who sees LPG at 49p/litre (compared to 74p/l for unleaded) has thoughts of doing the same.

I'd be more inclined to investigate biomass, especially the sugar->methanol route, as it'd re-energise the sugar beet industry here.
posted by holgate at 7:43 AM on January 20, 2001