Driven by abundant supplies of low-cost natural gas and sustained higher prices for gasoline and diesel fuel, the number of natural-gas vehicles will nearly double between now and 2020, according to a new report from Navigant Research.
The number of natural-gas vehicles on roadways worldwide will jump from 18.2 million in 2013 to nearly 35 million by 2020, the report predicts.
"NGVs experienced a brief surge in popularity in the 1970s and early 1980s as a result of the 1973 oil embargo and the price shocks that followed," said Dave Hurst, principal research analyst with Navigant Research.
"Today, growth in the market is being fueled less by negative external events and more by positive industry developments, such as increased vehicle availability, a stronger focus on the largest users of fuel in new regions, and a greater openness to alternative-fuel vehicles on the part of motorists and fleet operators."
Natural gas, which exists as a gas at ambient air temperature, must be compressed or liquefied in order to increase the volume of fuel that the vehicle can carry and to improve the vehicle's range, the report explains.
Compressed natural gas is compressed to 3,600 pounds per square inch. Liquefied natural gas occupies about 30 percent less space than CNG, but the gas must be super-cooled to minus 259 F before it liquefies.
While more LNG fuel fits into the same amount of space as CNG, LNG tanks are larger, heavier and more costly, according to the report, limiting LNG to medium- and heavy-duty trucks and buses.