CGN versus Prius. Cleaner or just a political thing?

CGN is lower in CO2 emissions, but does cause a little more engine wear (less lubricating than gasoline. A Prius running on CNG (it can be done) is a better choice if you are concerned about cabon emissions.

JeffD

 

I have read a couple of articles on this and if I am remembering correctly CNG is quite a bit cleaner in terms of emissions - both from the standpoint of the burning of the gas as well as the fact that the gas is very pure and contains almost nothing in the way of contaminants such as sulphur, etc.

As for just how it compares to the Prius I'm not sure, but I would imagine that you are looking at something like very good for the Prius and very, very good for a similar CNG car. I think the real benefit in CNG is that it works in other applications than the small car in ways that hybrids do not. I believe that CNG engines produce high-torque so they are suited for trucks and buses and other fleet vehicles. For example the taxis in Buenos Aires are all CNG. I think it would be prefect for a company like UPS or Fedex if they could work out the kinks.

One of the big issues with CNG in vehicles is that while many cities do have natural gas lines, those are all relatively low pressure, and you need high pressure to fill a car's tank. I remember that Utah has a large number of CNG cars and trucks - they have some funky tax/state ownership that makes CNG very inexpensive. Supposedly fueling stations run quite a bit slower in the afternoon because the high pressure tanks have been drained so much over the course of the day.

 

My recollection is that the Civic CNG and Gen 2 Prius are very close in emissions per the EPA website. The advantage in California is that the Clean Air stickers for the CNG cars are still valid (allowing lone driver to use HOV lanes) while the Clean Air stickers on the Prius will be expiring soon.

 

The -problem- with CNG is range. You can't get a lot into a reasonable size tank. So you often end up with a car that can go 150 mi. before refueling. There are ships that carry natural gas, but to make it practical they have to cryogenically cool the gas to liquefy it.

Like hydrogen, right now it's just not a very practical fuel for automotive use. Which is why it doesn't sell unless there are subsidies. Funny that a HOV lane sticker is worth that much. Glad I don't live where traffic is that bad!

 

Theoretically, if you make $33.33/hour, and you either work three hours more or drive an extra three hours (1.5 hours each way, which should be within possibility), it would be $500/week, or $25K/year, enough to pay for one of the CNG vehicles new. OK, it isn't including taxes and it figures you'll work instead of relaxing at home for 3 hours, but it shows how quickly the time adds up sitting in traffic. On the other hand, you'll probably be able to fly in the HOV lanes with just three other CNG people in them instead of all the Priuses.


In California, it is "unlimited" to the number of white stickers for CNG that can be distributed: Eligible Vehicles - Single Occupant Carpool Lane Use Stickers . One thing though is that these stickers are due to run out in 2015, and if they aren't renewed you've got a much less valuable CNG vehicle out there.

 

NG starts out with about 2/3rds the CO2 intensity of petroleum, but a Prius is about 50% more efficient than a non-hybridized NG car. Ends up a wash CO2 wise. But NG has close to zero NOx, HC, particulate and Sox emissions, so given CARB's historical emphasis on those pollutants NG cars are an EV equivalent in the context of tailpipe emissions and are therefore accorded the same perks as an EV.

Don't shoot the messenger

 

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Re: CNG versus Prius. Cleaner or just a political thing?

Yes. At the time the yellow carpool sticker program was developed, the State of California wanted to encourage the sale of hybrid vehicles that would yield 45 mpg or better. However if you visit CA now you'll see that hybrid vehicles are like mushrooms, so there is no need to offer further incentives.

In the past, the white carpool sticker was available for a variety of CNG vehicles, some of which are substantially larger than the Honda Civic. However I see that for the 2011 model year, the vehicles that can obtain this sticker are electric and small CNG cars.
Eligible Vehicles - Single Occupant Carpool Lane Use Stickers

 

Yes, as Patrick explained, the hybrids were allowed to get the Clean Air stickers as an incentive to get more people to purchase them. It isn't necessary any longer.

The incentive now is California gas prices which are closing in on $4 / gal again after dropping when the economy took a nosedive in 2008.

 

The white stickers are for alternative fuel vehicles not limited to the Civic CNG, Tesla, Clarity or other production cars. I've seen many white stickers on converted EVs as well.

 

I'd like to see people focus on all harmful emissions and not just CO2.

Just about every source of media has someone claiming diesel or a biofuel is cleaner because it emits less CO2 but they fail to compare all of the other harmful pollutants. It's rather irritating.

 

Yes but it allows them to drive their 4 door, 4wd, biodiesel fueled pickup trucks and feel good about helping the environment. :madgrin:

 

To be fair, they are doing better than the typical Hemi owner. lol

 

hey there,

Im a newbie here. are there any conversion kits out there that will allow us to convert our Prius to use CNG instead of unleaded?

Thanks

Ed lin