I agree, interesting topic. I like how it's mostly staying on the original subject of the practical, "guy buying gas at the pump" economics.
In that vein, some of the terminally bored might be interested to know that this was one of the hotter topics when I was a graduating Chemical Engineer back in 1995. At the time, the AIChE (American Institute of ChemE's) had as their annual "contest problem" a conceptual design problem for a chemical plant that would take methane and convert it to methanol for fuel for automobiles.
The premise, as I recall, was to determine if the plant could be profitable (defined in this context as a 15% internal rate of return) with the average price of a US gallon of gas sustained at $5. Sounds a bit too prescient, doesn't it?
Anyway, as a simplification of the problem we were allowed to assume virtually unlimited supply of natural gas, independent of other economic pressures and competition from demand, but it still came with a non-linear cost per unit of gas ... which is how it would work anyway. My solution? Well ... if you could put up $150-300 million or so
you could be making lots of money (if everything remained stable) in about 10 years. Don't laugh, I actually got an A in that class and the Prof submitted it to the national judges. They balked at the price tag, dooming me to a career in federal government service where things like "cost" and "hundreds of millions" don't really mean the same as to private corporations ... damn short-sighted bastards.
Having said all that, you can bet that someone, somewhere, is looking very hard at this. And it won't take a genius to figure out that it's someone with LOTS of natural gas reserves. According to some quick searching, the US is in 6th place over all with about 7% of the world's total, but what really matters is who's got more than the US: Qatar, Iran, China, Russia are all in there, with Russia at #1. I think China is in fact already making and running methanol in their cars - but I think they're getting methanol from coal (which they have loads of as well) to use it up before going to natural gas. Of course, one can get methanol from biomass too ... just about any source of methane will do. [insert fart jokes here]
Methanol has some pretty significant advantages over straight-up CNG, most significantly it's higher available energy per tank due to its higher density as a liquid vs. a gas at STP (not energy density, actual density). That means, of course, that one can go much further on a single tank. (As a result of this physical density difference, methanol has a higher energy density per unit volume than methane does because of it's higher physical density ... unless you liquify the natural gas to LPG, which has some issues with keeping it a liquid and not exploding with a BLEVE under some relatively common automobile accident conditions. Interestingly enough, the
specific energy, as in energy per unit mass, is higher for methane than methanol, ethanol, other natural gas blends with propane/methane, and even gasoline and diesel. But hydrogen gas beats 'em all by a LOT ... it's just hard and dangerous to keep liquified, dammitall)
So if you ask me, we are going to live in Interesting Times for the next 50-100 years or so.
typo corrected
