Is Civic CNG an environment-responsible choice? - Fuel Economy, Hypermiling, EcoModding News and Forum

theaveng · 08-14-2014, 05:11 PM

Or is EV better?
Or hydrogen FCV?

What technology should I be supporting? I'd like to hear thoughts/opinions on it. (Personally I'd rather see CNG cars than CNG-converted-to-run hydrogen cars.)

2000mc · 08-14-2014, 05:20 PM

this is the reason i dont own a cng vehicle Alternative Fuels Data Center: Natural Gas Fueling Station Locations maybe it wouldnt be an issue for some people

theaveng · 08-14-2014, 05:22 PM

I have one directly across the street from me (which is why I considered a Civic CNG). There's also a hydrogen station..... about 10 miles away! Not convenient at all.

The Civic CNG was a bit boring to testdrive. It felt like a normal car..... unlike a hybrid where you can feel the electric kick-in for extra assist.

It's cheap to run at only $12-14 a tank.

oil pan 4 · 08-14-2014, 05:50 PM

There are almost no hydrogen stations any where else and have you priced hydrogen?
It should be very expensive. I would be surprised if it was less than $5 per GGE.
Hydrogen is not as green as natural gas. The hydrogen is made from natural gas. The Carbon is still turned into CO2 and released. At least with direct combustion of natural gas the formation of CO2 actually helps move the vehicle down the road.
Kind of makes you wonder, whats the point of stripping the carbon out of the natural gas, guess its just so they can charge you a lot more money for the same amount of energy.

theaveng · 08-14-2014, 06:53 PM

The EVs have the advantage of home refueling (plug into the wall).

Also I see the Civic has a high compression ratio of 13:1 because CNG is 120 octane! Burning the CNG directly in a Civic may be better, except I don't know how "clean" that process is? I imagine it produces NOx, HC, and carbon monoxide just like any other imperfect combustion process. The Civic CNG is rated no cleaner than a Prius C by greenercars.org (and less clean than the original 70mpg Honda Insight). Here's the CNG-to-H2 production:

(1) Steam-Methane Reforming Reaction
CH4 + H2O (+heat) ---> CO + 3H2

(2) Water-Gas Shift Reaction
CO + H2O ---> CO2 + H2 (+small amount of heat)

(3) In a final process step called "pressure-swing adsorption," carbon dioxide and other impurities are removed from the gas stream, leaving essentially pure hydrogen.

Steam reforming can also be used to produce hydrogen from other fuels, such as ethanol, propane, or even gasoline. Natural Gas Reforming | Department of Energy

cRiPpLe_rOoStEr · 08-14-2014, 08:49 PM

CNG has its positive aspects regarding the "environmental performance". OK, it's nowadays still mostly sourced from fossil reserves, but since it can be sourced locally in America its logistics are less energy-intensive than petroleum-derived fuels, so it's already a good advantage. CNG can also be sourced from biomass in sewage treatment stations and waste management landfills, so in a comparison to other biomass-based fuels it has an advantage because it doesn't have a higher impact on food production as ethanol and biodiesel are often pointed to do.

theaveng · 08-15-2014, 03:42 PM

California provides hydrogen free to anyone who leases a fuel cell car. You are given a debit card.

The longterm plan is to produce hydrogen from CNG and sequester the carbon dioxide under the Sierra mountains. That seems like a good plan until you remember the mountains were created by earthquakes & eventually the CO2 will likely escape:

https://en.wikipedia.org/wiki/Lake_Nyos#1986_disaster

serialk11r · 08-15-2014, 05:27 PM

Let's be real, CO2 is going to be emitted for a long time by burning fuels, and hydrocarbon fuels happen to be a great energy storage medium. With all the emissions control equipment on cars right now, I don't think emissions is a huge deal when a diesel truck rolling by with its lax emissions controls would be emitting way more NOx than god knows how many cars even if it were running natural gas.