The existence of absurd EPA regulations is not a surprise. However the claim that a car can be converted to CNG for "a few hundred dollars in parts and labor" is unbelievable. You can't just throw a couple of barbeque grill tanks in the trunk. A DOT-approved CNG tank will be roughly $2000 - $3000 all by itself, based on prices at http://www.cngconversionsonline.com/
Add in other parts and labor and I'd ballpark it at around $5,000 minimum. And it has to be done properly: you don't want a CNG leak in your garage overnight. Some sort of certification of installers is warranted.
It costs "a few hundred dollars in parts and labor" in Moscow, Russia ($400 [Lada] - $1500 [Chevrolet Suburban], Russian, Polish, and Italian parts), based on price lists on the web. Labor is cheaper here, but it takes from 4 (most cases) to 12 (non-standard cases) hours to install.
You're also probably ok without an EPA license in Russia or India. The complaint's probably valid in the context where it matters. But either way--taxing 300% or 3,000%--that's a travesty for an organization that's purportedly dedicated to preserving the environment.
In India, a hack conversion (not approved by government) costs about $200 in parts + labor (not including the tank). And yes they use a domestic gas tank (similar to barbeque grill tank) kept in the trunk.
It's important to note that LPG (liquefied petroleum gas, mostly propane) is very much not the same thing as CNG (compressed natural gas) from an engineering perspective.
CNG tanks have to keep much higher pressures and are therefore quite a bit more expensive. As a previous commenter noted, $2k-$3k just for the tank is about right, at least for a new, light unit. If you're willing to go the solid steel route, you can probably still get something old and heavy [1] for under $1k, but good luck finding capacity at under $100/GGE (gasoline gallon equivalent).
Lastly, there's the safety question. Currently, CNG cars have remarkably good real-world crash experience. I don't believe there's a single tank burst or fire in a collision [2]. I'd be curious to know if other countries, with more lax regulations, have as good safety statistics.
TANSTAAFL
LNG (liquefied natural gas) is also quite different from LPG. I've looked into it, if only as an emergency reserve fuel tank. Turns out that to store it indefinitely requires refrigeration (or, presumably, absurd amounts of insulation), else it'll boil off, escaping out the pressure relief valve installed in the tank for just such an eventuality. Fortunately, like a pot of water on a stove, it doesn't all boil off at once, so there's little risk of leakage if one always uses enough vapor to keep the pressure down.
[1] To the tune of hundreds of pounds. This is less likely to be a concern for converting trucks, but I notice a fuel economy difference carrying just one adult passenger in my Civic GX.
[2] I haven't looked this up in the last 3 years or so. Corrections/updates are appreciated.
That's for autorickshaws, which are closer to a motorcycle than an automobile.
The fuel economy quoted in the article (40km/kg) is around twice that of my Civic GX (30mile/GGE=30mile/5.660lb=30mile/2.567kg=51.5km/2.567kg=20km/kg), which is consistent with motorcycle numbers.
They also quote an autorickshaw traveling around 100km per day. Since the Civic with an 8GGE tank has a 400km range, the autorickshaw tank would need to be 1/16th the size. Assuming tank costs are linear and a new 8GGE tank is $3k, that puts the rickshaw tank at under $190.
I suspect the non-tank portion will also scale at least linearly with number of cylinders. Assuming a single-cyclinder motorcycle engine and 4 cylinder car, that runs the price up to $4k total, which, unsurprisingly, is still cheaper than here in the US but not by $10k.
Short answer: because it has a lower carbon:hydrogen ratio.
NG is mostly methane (minimum 88% if I recall the stickers on the PG&E "pumps"), with 1 carbon and 4 hydrogens. The rest is made up primarily of also fairly short (2-4 carbon) chain hydrocarbons.
Traditional gasoline is heptane (7 carbon) and octane (8 carbon).
Methane's ratio is 0.25.
Heptane's ratio is 0.4375, and octane's is 0.4444. (Longer chains asymptotically approach 0.5).
I get the same economy (30-33 mpgge) in my Civic GX as in my gasoline Civic.
However, let's compare carbons based on molar mass (16.042 g/mol for methane and 100.21 g/mol for heptane and octane is 114.23g/mol). That's 160 moles of methane per GGE and 27.5 moles of heptane per gallon. That's a ratio of 160:192 of carbons. For octane, that's 24 moles per gallon, about the same ratio. It's not 1:4, granted, but these are just hand-wavey approximations for the gasoline, which has the added complication of ethanol. I'm also assuming complete burning, which is patently false, considering that, before modern emissions controls, it was possible to commit suicide by carbon monoxide poisoning from engine exhaust.
Add in other parts and labor and I'd ballpark it at around $5,000 minimum. And it has to be done properly: you don't want a CNG leak in your garage overnight. Some sort of certification of installers is warranted.