What gas are you going to choose for your next car?

When you think of German vehicles, odds are that you're picturing big Mercs and Bimmers speeding on the Autobahn. However, the German market is quite diverse and there's a good supply of alternative fuels to be had. You can get most models powered with gasoline, diesel, natural gas (CNG) or liquified petroleum gas (LPG, also called Autogas). While the debate between the first two choices is quite old, how do you choose between the two latter alternatives? While you can convert a gasoline car to run on LPG, you can't do this with CNG. So which one to choose?

First, let's speak about the cost of fuel itself. According to TÜV Süd, a kilogram of natural gas has the same energy content as 1.5 liters of gasoline. When it comes to costs, the average price of driving with CNG is half of the cost of gasoline. As for LPG, two liters have the same energy as 1 kg of natural gas. This makes LPG about 30 percent more expensive than CNG (and about 35 percent less than gasoline).

There's more after the jump.

[Source: Auto News]

We can't ignore the different cost of the LPG/CNG conversions. Usually, a gasoline-to-LPG conversion costs between €1,800 to €3,500 although some brands are starting to offer them as standard equipment, guaranteed. No CNG conversions are offered and these models usually have a €2,800 to €5,500 surcharge from its gasoline counterparts, although sometimes they cost about the same as a diesel model. A good rule of thumb: if you drive less than 10,000 km per year, stick with a fuel efficient gasoline vehicle.

What about the environmental balance? Both CNG and LPG have the smallest environmental impact among the fossil fuels. Their emissions of CO₂ per km are usually 25 percent lower than equivalent gasoline cars, and smog production is about 80 percent less. Particulates, NOx, carbon monoxide and sulfur dioxide emissions are almost zero. Germany is also investing in obtaining biogas from renewable sources, usually waste, which would make CNG more interesting.

Currently, up to 3,000 gas stations in Germany offer LPG pumps, compared to 800 stations offering CNG (although this number is increasing). There are tax advantages to using these fuels, too, although LPG might lose its privileged status in 2018. A taxation scheme based on CO₂, which will be introduced in Germany soon, might keep these two fuels as a viable options.