3.7 Natural Gas

Natural gas can be used as vehicle fuel in a gaseous (compressed) state (CNG) or a liquefied (refrigerated) state (LNG). Similar to propane, because of the relatively simple chemical structure of natural gas in comparison to traditional vehicle fuels, there are fewer toxic and carcinogenic emissions from natural gas vehicles and virtually no particulate emissions.⁵

Currently, the only natural gas light-duty vehicle available in the US market is the Honda Civic GX. There are no OEM natural gas light-duty vehicles available in Canada. The majority of the natural gas vehicle market for light-duty vehicles has been met with aftermarket conversion technology. There are, however, a number of heavy-duty vehicles available on natural gas (CNG or LNG). These are transit buses, heavy-duty tractors and medium-duty trucks. These vehicles are generally powered by compression-ignition engines converted to spark ignition engines by the major engine manufacturers such as Cummins. The market for natural gas heavy-duty vehicles and transit buses is more developed in the US than in Canada primarily due to Federal Government incentives for urban non-attainment areas to replace their diesel-fuelled buses and trucks.

Similar to propane, natural gas as a vehicle fuel experienced setbacks in the 1990’s as the outdated carbureted technology caused operational and emissions issues for fleet users. Like the propane industry, the natural gas industry has now moved to fuel-injection technologies and is consistently achieving excellent emissions results and reliable performance. High conversion costs and limited government incentives have caused the market for natural gas-powered vehicles to decline in recent years. Conversion costs remain high relative to other alternative fuels, as the high-pressure cylinders are costly and often, multiple cylinders are required to yield the operating range required for a fleet user.

Refuelling infrastructure is relatively expensive with capital costs in the $250,000 to $2,000,000 range, depending upon capacity. As a result, there are only about 100 natural gas refuelling sites in Canada. It should also be noted that vehicle refuelling rates for natural gas are much slower than liquid fuels and propane.

⁵ www.naturalgas.org/environment/naturalgas