The 2015 Silverado and GMC Sierra HD’s bi-fuel, gasoline-compressed natural gas offerings will now be available in all cab configurations, short and long box, and two- and four-wheel drive models, in 2500HD and 3500HD series. GM’s 6-liter V-8 with hardened valves and valve seats allows the vehicle to operate on gasoline or compressed natural gas. The driver can switch between fuels at will; when the CNG tank is depleted, the system automatically switches to gasoline. The pickups have a standard combined gasoline-CNG range of more than 650 miles, GM officials say. With CNG currently priced about 62 percent less per gallon than gasoline, a work truck driven 26,000 miles a year can realize a fuel-cost savings of more than $2,000 annually, based on 75 percent CNG usage and comparable efficiency to gasoline, GM officials say.
