General Motors announced the cost of bi-fuel conversion kits for the 2015 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD pickups. This allows the trucks to run on both petrol and CNG, boosting their economy and range. CNG is more than a dollar cheaper than an equivalent gallon of gasoline.

Prices for compressed natural gas conversion start at $9,500 for the Chevy Silverado and GMC Sierra. It is only available for the single-rear-wheel models.

For the 2015 Chevrolet Express and GMC Savana cargo and passenger short-wheelbase vans the treatment will cost $10,825 for the three-tank system and $12,090 for the four-tank system. These vans have fully dedicated CNG fuel systems – available in three- or four-tank models on cargo vans and exclusively with the three-tank design on passenger vans.

GM’s factory-fitted CNG kits come with a five-year/100,000-mile powertrain warranty and are tested and validated for safety. This is something best done by the car maker, as botched installations are effectively time bombs.