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Discussion Starter #1
I know Ford and other manufacturers made quite a few (mostly fleet) vehicles that had gasoline AND compressed natural gas tanks, and the driver simply flicked a switch on the dash to switch between the fuel sources.

My suggestion for GM is to make a dual CNG + E85 Flex Fuel powered genset (so you can run on regular gas station gas or CNG from home or from a gas station). The obvious problem would be the space and added weight (about 150lbs) for the CNG tank. But if they could solve this, you have the option of:

Plugging in your batteries to house power. (for 40-mile range)
Plugging in your CNG tank to house natural gas. (for extended range)
Use CNG from the gas station. (for extended range)
Use regular gas (or up to E85) from the gas station. (for extended range)

http://www.myphill.com/

CNG and electricity from home is cheap, clean, and convenient. You just plug in before you go to bed and unplug when you are ready to drive to work. And while the batteries can't quickly be recharged on-the-go, you can still refill with CNG or gasoline from a refueling station (a station near my house offers CNG).

Of course, as I mentioned, the obvious problem is that you have three large and heavy energy storage devices on one vehicle that must be carried by the batteries while on AER. But just imagine how cool and flexible a quad-fueled vehicle would be. You could run on Batteries, Gasoline, FlexFuel, or CNG; two of which can be charged right at home, three of which can be obtained from a gas station.
 

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I know that in Europe GM offers dual fuel systems. I think they offer both propane and natural gas options. Why they don't bring that technology to North America is not known to me. Maybe it has something to do with safety (????)

I know a Chevy HHR owner in Germany who has a dual fuel system direct from GM (not an aftermarket install.) He says that it's hidden under the rear cargo floor in the spare tire location. It doesn't take up any usable space, other than eliminating the spare.
 

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Discussion Starter #3
http://automobiles.honda.com/civic-gx/

Honda is the only new car available in the US with CNG. Looks like all the bi-fuel vehicles made by everyone else are only available through fleet orders (you can find a few older cars on ebay motors by searching "bi-fuel" or "cng").

Here's an interesting article:

http://www.hybridcars.com/compressed-natural-gas/cost.html

There are at least 4 gas stations in my area that have CNG available. And it's only about $1.00 (per equivalent gallon of gas).
 

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Discussion Starter #4
Why they don't bring that technology to North America is not known to me. Maybe it has something to do with safety (????).
CNG is "safer" than gasoline since it has a narrower ignition window than gas and also disperses better than a liquid (which just pools and burns). CNG is safe enough for use in homes (most homes have CNG stoves, heaters, driers, hot water heaters, etc...). It just faces the two problems that hydrogen also faces today.

1) Low availability. There exists infrastructure, we have the technology to safely and cheaply use 3500psi pressure vessels on vehicles, but most stations don't supply CNG since they don't see cars that use it. Basically, the only people that use it now is the federal government.

2) Pressurization. Rapidly-refilling a pressurized container results in less energy stored due to the rapid-refill effect (heat is generated, higher heat means less gas is stored, meaning the tank cannot be filled completely without a cooling system, which is impractical and too costly for use onboard a vehicle).

But everything else is for CNG. It's safe, it's cheap, it's clean, it's low tech, etc... I see CNG as being an even better current-day alternative to gas than hydrogen could ever hope to be.
 

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GM definitely needs to offer at least a CNG option. Consumers should not have to purchase any gasoline with the Volt!
 

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CNG makes a lot more sense than hydrogen, at least in the near-term. Almost all currently-available hydrogen is made by re-forming natural gas, with about half the energy in the natural gas lost in the process. The argument about reduced GHG's from H2 is silly, as there really aren't any viable carbon sequestration processes developed yet for small H2 production facilities.

From what I've seen most near-term plans for installing hydrogen re-fueling stations are based on using the same gas re-forming technology. Electrolysis-produced H2 is still pretty long-term.

CNG would give a cost-effective alternative, IF natural gas prices remain lower per-BTU than oil.

OK, Jason, I know you'll chime in to correct/update me on the latest in H2 technology, so have at it and thank you for whatever new information you can contribute.
 

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Discussion Starter #7
GM: A CNG/Gas dual-fuel Volt would be the ultimate car. Exploit the flexibility in E-Flex from the very beginning. Otherwise it's just E-Rigid, and that doesn't sound very exciting.
 

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Aren't you guys afraid of the speculators? Once they realize we are switching over the infrastructure they will jack up the prices. Oh wait maybe it really is supply and demand based. ;)

Also, remember that natural gas just another non-renewable resource. This means it might help in the short-term but it will also see a run up in price and eventually peak gas will arrive.
 

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Discussion Starter #9
Horse ---> Gasoline ---> __???__ ---> Electric


Something has to replace gasoline now. It won't be hydrogen, and it can't be ethanol. It has to be something that we have an infrastructure for already and that is supplied domestically. As long as we get something until we can develop an energy storage device that can accept rapid recharges at a low cost, it will be good enough. It doesn't have to last more than 20 years.

Look at Picken's Plan. We release all natural gas away from power production and we put it to transportation. The switch won't have any major impact on supply/demand because we are removing the demand for natural gas from power plants (which is HUGE). The switch won't replace imported oil 100%, it's only 38%, but that's good enough.

So we need something to be the bridge (20 years) to electric or hydrogen. What options do we have?

The ultimate solution would be a gasoline/CNG dual-fuel EREV. That way you drive your first 40-miles on very cheap, clean, domestic electricity. Then you drive the next 160-miles on cheap, clean, domestic natural gas. Then you drive the next 300-miles on expensive, dirty, foreign gasoline OR you just find a CNG refueling station (I have 4 near my house) and refill on CNG and never pay another penny for gasoline.

So I'll take the Volt with a dual-fuel (gasoline/CNG) genset. That's truly an E-Flex.
 

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Aren't you guys afraid of the speculators? Once they realize we are switching over the infrastructure they will jack up the prices. Oh wait maybe it really is supply and demand based. ;)

Also, remember that natural gas just another non-renewable resource. This means it might help in the short-term but it will also see a run up in price and eventually peak gas will arrive.
A couple strong points for potentially using natural gas are that:
1. The supply/demand market is a North American market and not a global market. Prices should be easier to control (should better follow supply and demand trends.) It should be easier to monitor price and the speculator market.
2. Natural gas typically requires much less processing. Unlike oil natural gas does not need to be upgraded or processed into fuel.
3. Natural gas is much easier to bring to market. It is easier to increase the supply to meet demand as compared with oil.
4. North American sourced. Partial energy independence can be acquired because much of the natural gas supply comes from domestic sources or from BC, Alberta and Saskatchewan (Canada.)
5. Natural gas supplies are fairly plentiful. Yes, "peak" can be reached at some point if everyone "pigs-out" on the stuff.
6. If a significant portion of the auto were running natural gas that could lower oil prices and necessary refining into gasoline and shift capacity to diesel. Diesel is the life-blood of the trucking and shipping industry and hence the lower would trickle down to consumer products.

These are just some of my thoughts of the top of my head. Some may be more true than others and I'll have to look up some facts and sources but I forsee a positive movement towards natural gas as an automotive fuel.
 

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Love the idea of gas/E85/CNG, that would be cool. However, this feature would be a significant added expense and to keep the purchase price down I don't think it has a chance. Also as was pointed out earlier, I really don't know where they would put the CNG tank without going right into the passenger/cargo are of the car. So we can dream, but ainnagunnahappen.
 

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Discussion Starter #12
The Chevy Cavalier CNG/Gasoline model had a standard gas tank where the gas tank goes, and a CNG tank in the trunk (up against the back of the back seat). The trunk space was reduced roughly by half, but there was still plenty of room back there, and there was no sacrifice to passenger space.

The benefit of dual fuel over single fuel CNG is you can sacrifice pressure vessel size because you can still rely on regular gasoline as a backup (just like how the Volt sacrifices battery size and cost because it has the genset to fall back on). So CNG tanks don't have to take up passenger space.

The Volt concept had a more open design, so it's hard to say what that trunk/hatch volume of the Volt will be. But I would guess that since the batteries are in the T and the genset is up front, the back will have enough room for a small CNG tank.

The cost of CNG isn't that much. Even at roughly $22K, the only company that sells CNGs to the general public (Honda) can't make enough of them because demand is so high.

If people realize the fuel cost savings and environmental benefits to a 3-stage fuel system (electric > CNG > gas), I think they would pay more for the upgrade. I don't think base models should be CNG, because that would raise the cost too high, but it would be nice to be given the option to upgrade.
 
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