Right now the efficiency over oil is enormous. At current market price youre getting over 3x the energy per dollar for natural gas, IIRC. Methane is also by definition the cleanest burning hydrocarbon, with the fewest CO2 molecules per energy provided. In the US alone, it's estimated that nat gas has the average household pocketing $800 yearly since the fracking boom. In addition, a geoscientist recently told me it's estimated that we're only extracting about 10% of the natural gas available per well, meaning there's tons more down there. It has serious potential, and at least the US's electric infrastructure is rapidly changing to accommodate it. Anyway, what I'm getting at is maybe we shouldn't count out natural gas.