The United States are far behind Europe when it comes to cars running on Compressed Natural Gas (CNG). Fiat is the European leader, followed by the Volkswagen group, and both are selling several tens of thousands of CNG cars each year. With Chrysler, Fiat is eager to launch CNG cars in America, but this is General Motors which is the first to launch a full size sedan with a CNG option. The problem is that it isn’t at the same level as the CNG cars sold in Europe. Far from it.

All CNG cars are bivalent, able to run on gasoline or CNG, ideally without the driver noticing any change, but the goal is that CNG should be the main fuel. So the CNG Volkswagen up! comes with a 11-kg CNG tank and a small 10-liter fuel tank. Another model, the CNG Mercedes B-class has a large 21-kg CNG tank and a small 12-liter fuel tank. On both models, the range on CNG is more than three times the range on gasoline. Not so with the CNG Impala, which has a small CNG tank. GM says its range on CNG will be a modest 150 miles, while range on gasoline will 350 miles. So CNG may be the cleaner and cheaper fuel, but unless they can refill at home, drivers will most likely prefer the convenience offered by regular gas…