[nagant]

It still emits eeeeevil carbon dioxide.
~~~~~

True, but it emits much less carbon dioxide. The reason why CNG is less energy dense is that its molecules have far less carbon to burn... for what it’s worth.

In my book, that and $.50 will get you a McDonalds senior coffee.

[E. Pluribus Unum]

True, but it emits much less carbon dioxide. The reason why CNG is less energy dense is that its molecules have far less carbon to burn...

That also means you have to burn more of it per mile, so it probably emits pretty much the same amount of CO₂ per mile.