Compressed natural gas/biogas is available today and has been for years, at prices far below that of electric cars, with none of the range and refueling issues that electric cars have.
STOP BUYING OIL FROM OPEC. We cannot bring peace to the Middle East. We cannot force Afghanistan to be a democracy. Let us do something we can do. Stop buying oil from OPEC. We can do it now. Compressed natural gas (CNG) cars. Iran does it. So can we.
We still import 4 million barrels per day from OPEC. But now, we have the capability to stop all oil imports from OPEC within 60 months. We have low cost natural gas and low cost technology for converting cars to operate on CNG. This program would convert 65 million vehicles (23% of our fleet) to (CNG). Cost $98 billion. The other part of the program is to build 10,000 CNG refueling stations. Cost $20 billion. Total $118 billion. All the costs will be money spent on U.S. labor and material. Use of low cost natural gas will save us about $80 billion per year.
The program can start immediately by presidential order to convert the 600,000 federal non-military vehicles to CNG. Theses are shovel/wrench ready projects. Total cost: less than $5 billion.
This CNG program is not like the Manhattan Project that involved large technical uncertainties and risk. CNG technology is commercially available in the United States. Iran now has 2.9 million vehicles (23% of its fleet) operating on CNG.
The collateral benefits are manifold: cost savings; reduction in trade deficit; employment for 100,000 Americans; reduced CO2 emissions; low technical, commercial and environmental risks; progress that can be accurately measured; plus no political party would find it objectionable.
I was merely pointing out that hydrocarbons don't have to be liquid to be a viable vehicle fuel. Where I live, all the vehicle gas comes from sewage and municipal waste.
Compressed natural gas (ie, not liquefied) is the runner-up to purely battery electric vehicles. The problems are short range (go read the reviews of the Honda Civic GX: the range is comparable to the middle battery option in a Tesla Model S) and lack of natural gas stations.
The second problem can be partially ameliorated by filling at home with a high-pressure compressor (runs on electricity) fed by the same pipe that brings natural gas for your furnace and stove. Unfortunately, that still requires you to plug in the car overnight, just as you would with an electric, because fast high-pressure compressors are still very expensive. The compressor, by the way, costs more than an 80A EVSE for an electric car and adds range more slowly. There are a few public stations that store high pressure gas, but they tend to be at places like airports and taxi maintenance yards, where fleet vehicles congregate (check out Edmund's review of the Civic GX for refill times, though, they aren't nearly as fast as with gasoline). And compressing the gas still requires electricity. It is comparatively easier (and cheaper) to set up an EVSE (the "charger" stand, although it isn't really a charger) for an electric car than to run a gas line and install a gas compressor.
The first problem I mentioned doesn't really have a solution with a short time horizon: You need either more volume (a bigger car) or a tank that can hold more pressure (you think that everyone from SCUBA divers to NASA hasn't been working on that one for the last fifty years?).
Liquefied natural gas has it's own set of problems: people complain about the Tesla Model S losing a few miles of range while parked overnight, but the boil-off from a cryogenic container would be far worse (an uncovered dewar of liquid nitrogen boils off in "a few" hours; a big 150L dewar at 1 bar will last maybe two or three weeks).
It's not that I think natural gas is "bad," it's that as a physicist I can see that we already have technologies that work better (albeit slightly more expensively for now). The only thing natural gas seem to have going for it at the moment is that it is slightly cheaper[1] than a battery-powered car. Unless there is a new and obviously-practicable way to greatly improve the inferior technology in a short amount of time, I don't understand why it is worthwhile to spend money developing it.
[1] The Civic GX seems be to only available in jurisdictions (like California) that require a manufacturers to sell a certain number of "zero emissions" vehicles. Thus, it is probable that Civic GX's are "compliance cars" and that Honda takes a loss on each one sold. If you want to know this for sure, wait a few years until the full restrictions kick in and all "zero emissions" cars are required to actually have zero emissions: If the GX is still sold by then, I'll concede that it is a viable product (though I'd still rather spend my money on a something like a Leaf at that price point).
Natural gas is a non-renewable fossil fuel. Burning it generates carbon dioxide and particulate matter that causes cancer. It may not be as dirty as gasoline or coal, but it's still the same kind of thing fundamentally.
If we're going to retool the entire transportation infrasturcture-- engines, pumping stations, and refineries-- I think we should aim a little higher than a minor improvement. The big problems with gasoline are the public health problem from exhaust fumes and the fact that we will run out of the stuff eventually. Natural gas doesn't solve any of those problems, and it adds transportation and potential safety problems that gasoline doesn't have.
I'd be interested in hearing from a physicist / engineer how much greater the safety problems are with natural gas. There are articles out there like this: http://www.ksl.com/?nid=148&sid=4772381 But it's not exactly fair to compare a badly done natural gas conversion with a factory-installed unit. I have a vague idea that explosive gas is bad, mmkay, but it would be interesting to hear whether it could be made safe.
Interestingly enough, I think the safest vehicle in a crash is probably a diesel vehicle, since unlike gasoline, natural gas, or batteries, a spark cannot ignite diesel fuel under normal atmospheric pressure.
Compressed natural gas/biogas is available today and has been for years, at prices far below that of electric cars, with none of the range and refueling issues that electric cars have.