How about an alternative FUEL for your vehicle.  Most people think diesel
and WVO, but in Canada and parts of Europe propane can make sense.

I converted a Vanagon to propane a number of years ago.  Depending on the
where you live and the price of LPG, it can be more economical than gasoline
and cheaper than a diesel conversion.  Propane Vanagons are somewhat common
in the UK, where gas is very expensive. Belgium and the Netherlands also are
favorable to LPG.
Just today I finished converting my old Volvo 850 turbo 5 speed wagon to
dual fuel.  At the moment gasoline is $1.10 a liter and propane is $0.50 a
liter so the spread is unusually wide.  Most propane is a byproduct of
natural gas production, the rest comes from oil refineries.  Natural Gas is
traded independently from oil, but it is also high at the moment. Apparently
Canada only uses about 1/4 of the propane it produces, the rest is shipped
south to America.  We have a huge surplus which could be used for motor
fuel.
Another point, propane burns cleaner than gasoline or diesel and is
considered a "clean fuel" by some states.  Lower CO, NO, CO2 and
particulates than gas or diesel.

http://www.telusplanet.net/public/gary2a/rack/propane/propane.htm

Gary Lee