Driven by the lower cost of natural gas and the lower emissions from natural gas engines, compared to diesel fuel, operators of truck and bus fleets are increasingly shifting to natural gas vehicles and a new study quantifies by just how much.

Worldwide sales of natural gas trucks and buses are forecast to grow from 170,200 annually in 2013 to 398,400 by 2022.

The report, “Natural Gas Trucks and Buses”, analyzes the global market for trucks and buses that are in the medium duty and heavy duty gross vehicle weight classes, was prepared by Navigant Research, which is owned by the business consulting firm, Navigant.

“Demand for natural gas trucks and buses remains uneven on a regional basis,” says Dave Hurst, principal research analyst with Navigant Research. “In North America, where natural gas costs remain low, the number of vehicles is outstripping the development of refueling stations. In Asia Pacific, China and other developing markets are looking to natural gas to help address environmental woes in large cities. As a result, the total number of natural gas trucks and buses on the road by 2022 is anticipated to reach nearly 4 million.”

On average, the price of compressed natural gas is about 42% that of diesel, according to the report, while liquefied natural gas tends to be a bit higher, but sees significantly more variability than CNG.

Given the difference, the payback period for heavy duty trucks can be as short as 1.5 years in North America, says Navigant. The incremental costs are largely driven by storage tanks for the CNG or LNG, which account for between 53 % and 76% of the total incremental costs.