The Alternate Clean Transportation Expo held in Long Beach earlier this month was a spectacular display of engineering ingenuity by Natural Gas Vehicle providers. The event's theme was that America’s self sufficiency in natural gas has decoupled our energy resources from petroleum prices. But the consensus among the gathered engineers and scientists was to look beyond the current prices of petroleum alone, and consider that domestic self sufficiency includes keeping jobs at home.
The NGVs (Natural Gas Vehicles, which include Compressed Natural Gas—CNG, as well Liquefied Natural Gas—LNG) reduce greenhouse gas emissions almost 20 percent on medium and heavy duty models, and 30 percent on light duty vehicles.
All fuels, including natural gas, release energy by burning. But cleanliness and renewability are probably the single most talked-about aspect of NGVs. From energy field to vehicle engine, natural gas needs very little processing to make it usable, compared to crude oil, which is processed into gasoline by complex and expensive refining techniques. A naturally occurring fuel, its chemical formulation is about 90% methane, with smaller amounts of ethane, propane, butane and carbon dioxide, a high octane rating of about 120 – 130, and clean burning characteristics.
Biomethane gas is extracted from biomass, and is therefore renewable, and it can be produced economically in large quantities. Current estimates are that the US has proven reserves of over 1500 TCFs (trillion cubic feet) of natural gas which, by some estimates, should last for the next 100 years.
Potentially, natural gas will create jobs not only through vehicle manufacturing, but through the construction of new CNG stations. A landfill processing plant near Dallas, Texas, owned by a pioneering company in CNG station installation, Clean Energy™, creates up to 9,000,000 GGEs (gasoline gallon equivalents)of biomethane gas for fueling stations. It has agreements with airports in Tampa, New York City, New Orleans and Philadelphia to build CNG filling stations that will support ground transport vehicles and off-airport parking shuttles.
Of course, legitimate concerns have been expressed about the safety of natural gas vehicles. Notably, in a tragic 1998 accident a stopped bi-fueled Honda (a vehicle that can run on CNG or gasoline) was impacted by another vehicle moving at almost 100 mph. A fire started by the gasoline engine broke out.
NGV supporters counter that the 50 liter CNG tank was intact and remained secure in its support bracket, that NGVs are subject to same federal standards as regular vehicles, and that natural gas cylinders are thicker and stronger than conventional gas tanks.
The NVG safety record also includes a survey of more than 8,000 natural gas utility, school, municipal and business fleet vehicles that have traveled 178 million miles, in which the vehicle injury rate was 37% lower than in a gasoline fleet. Under federal and state regulations, fueling stations, indoor parking structures, repair garages and car dealerships must all meet high safety standards. Leaking gasoline forms puddles and creates a fire hazard; if the CNG engine leaks at all, the fuel will normally rise to the ceiling and disappear. Insurance companies nationwide have looked at the safety of natural gas buses and fleets and have no reservations about insuring them.
Hybrids were also on display at the Expo, including a notable innovation by Parker Hannifin Company. Says Tom Decoster, business development manager of the Cleveland-based firm, “We are going to let California know there are alternatives to electric and CNG.” Parker’s alternative is the hydraulic hybrid, with regenerative braking energy stored as a pressurized gas in a vessel. These vessels are known to be accumulators, which Parker compares to batteries. While stored electricity from a battery drives a motor, energy from an accumulator powers a pump-motor to drive wheels. This assistance increases fuel efficiency and sometimes permits a smaller engine.
Average fuel consumption for a conventional Class 8 vehicle is about 9,800 gallons per year. RunWise™, Parker’s vehicle, reduces the fuel consumption by 30 to 50 percent, depending on route density and operating conditions. “The more stops a vehicle makes during the day, the more efficient the system becomes relative to a conventional drive train,” Decoster says, adding that the NGV also reduces CO2 emissions, compared to a conventional vehicle, by 38 tons per year, the equivalent of about six midsize cars or planting 1,500 trees. It has reduced brake replacement cycles from every few months to almost 2 years. Parker’s technology is intended for refuse trucks and for fleets that need frequent stops, such as those run by FedEx and UPS.
This highly technical conference and engineering-driven trade show was innovative in one other way, too. Expo organizer GNA designed events to reach out beyond the technorati to ordinary consumers who -- it hopes -- will one day be its loyal customers.
Shashi Parulekar is a Los Angeles-based engineer. He holds an MBA, and served as Asia Pacific M.D. with Parker Hannifin Co in Michigan for over ten years.