Something interesting that I noticed a few weeks ago when I was last in the Netherlands is that many gas stations are installing LPG/Propane filling stations by the normal gas pumps. You can get a conversion done so your car runs on LPG and the cost of the fuel is about 1/3 of the price of gasoline there. My brother inlaw had it done to his car and I noticed no difference while driving compared to a gasoline powered car. He says his mileage and power seem about the same as before to him. The car starts on gasoline then automatically switches over to LPG once the engine is running and at a certain temperature. He has used 1/2 of a tank of gasoline in the past year since the conversion. The LPG tank fills the space where the space tire usually sits.
For those not in the know, LPG is liquid petroleum gas. It's a waste product from the oil refinery process and is usually what you see burning at the top of the stacks at a refinery. Smarter refineries are harvesting & compressing this gas instead of burning it off, and selling it as a fuel.
It's also highly coveted by the Protoss and Zerg...
Because it's a waste product, supply is actually rather limited as most refineries continue to dispose of it for some asinine reason.
LPGs been common enough in Australia for about 2 decades now.
Two problems with people going ape about though.
1) LPG tanks come in 150L and 300L varieties (most commonly) and people will lose a lot of boot space (or spare tyre space) on install. That's not the problem though. The problem is that that you will use all of this to fill an LPG tank, because although the tank mileage is similar to petroleum and gasoline engines, the consumption rate is a LOT higher.
I get about 26.8L/100km on LPG, versus 11.7L/100km on 98 octane petroleum.
It still works out to be a saving, but not as much as you'd think.
2) The price is low now, but as more people get it installed, and people start using it, the price will go up.
LPG was about $0.40/L here this time of year, two years ago. Last year, our federal Government offered a cash incentive for people to convert to LPG.
Prices are now around $0.80/L where as petroleum is $1.40L
It's gone from being 35% the price to about 60%, because demand has skyrocketed.
The cost per km is now roughly the same as diesel, which is only marginally better than petroleum (as they've bumped the cost of diesel recently as well).
Watch it happen in a market place near you!!