I Europe a lot of cars are using LPG instead of petrol.
It seems that any car can be converted easily from petrol to LPG by replacing the injection system and adding a tank.
The range of the LPG tanks is not very big but when the tank is empty you can switch to petrol mode with the flick of a switch.
In California Honda has been selling a natural gas version of the civic, and there is a home filling station available to fill up your tank overnight in your own garage from the natural gas mains.
Can I convert my Saab 95 2004 to use natural gas? Would it be economical? and how "green’ is a natural gas fueled car compared to petrol?
First, LPG is propane, stored as a liquid, like for a barbeque, while natural gas is methane, stored at much higher pressure as a gas, like what is piped to houses for heating. Either conversion is possible, fairly expensive, and, given all the resources used to make the tanks, equipment, etc., not particularly green. At $4/gallon there was a fuel cost advantage, but much of that’s gone now.
There are too many downsides to this. The cost of fuel is more than the cost of gasoline, the coversion process is expensive, and has side effects (you won’t be using your trunk anymore) and the fuel is a bit cleaner than petrol, but not what most would be really “green”. It’s not worth it.
Yes it can be done, there are even tanks that replace the spare, it is not cheap, but gas will not be cheap forever. It is better to use a mix as pure propane burns out the valves, as I understand it here is a link to one near me.
http://www.fireemup.com/
Contact a company that does conversions to verify the conclusions you are already making (easy conversion,ability to switch,filling from home).
You need exact answers for your type of car from the people that will be doing it.
You will get to extend oil change intervals,but many major downsides?
What is your motivation? just to see if it can be done at any cost?
The LPG/Propane conversions used to be really popular on older cars because it was really easy to just replace the carburetor with a gas regulator. You could even buy some that were combination carburetor/regulator so you could run on both. But with newer cars you really have to have a car that’s purpose-built to run on gaseous fuels. Even then, the economics of it don’t always work out because even though natural gas or propane are usually cheaper, sometimes much cheaper, compared to gasoline, you get significantly worse mileage with it.
In Europe, the popularity of them probably has more to do with cheaper fuel taxation than any kind of environmental concern.
It’s not worth the trouble.