Nowadays, electrified cars – from all electric to plug-in and extended range hybrids – are the alternative fuel vehicle darlings of the automotive world. It’s understandable since they put a kink in the imported oil pipeline, produce zero or near zero emissions, deliver excellent economy and buyers may even drive away with a car full of warm fuzzies.
But another alternative option is once again grabbing the attention of automakers, compressed natural gas, or CNG.
Compressed natural gas, a fossil fuel composed mostly of methane, is the same type of gas used to heat homes and light up kitchen ranges. But instead of running through pipes, it is stored at high pressure (2,900 to 3,600 psi) in special vehicle tanks normally mounted in the bed of pickups or trunks of automobiles.
As a transportation fuel, CNG produces approximately 25 percent less greenhouse-gas emissions compared to gasoline as well as a significant reduction of particulates and carbon monoxide, according to the U.S. Department of Energy. Natural gas vehicles (NGVs) meet the strictest emissions standards, including California’s AT-PZEV standard, and is considered an alternative fuel under the Energy Policy Act of 1992. (Liquefied natural gas (LNG) is used primarily by over-the-road tractor trailers, so it isn’t covered here.)
There are two types of CNG vehicles, dedicated and bi-fuel. Dedicated versions are designed to operate only on natural gas. Bi-fuel models have two separate fueling systems enabling them to run on either CNG or gasoline, and can switch from one fuel to the other in a near seamless manner.
Currently, four major automakers – Chrysler, Ford, General Motors and Honda – offer 10 dedicated CNG or bi-fuel CNG vehicles in the U.S., an increase of seven offerings since the fall of 2010. Of these, only Honda offers a CNG automobile, the Civic Natural Gas model. The other nine are either heavy-duty pickups, vans or chassis models, an indicator that the majority of buyers are commercial fleets, even though they are available to retail consumers.
A Prior Spurt of CNG Vehicles
This interest in natural gas isn’t new; we’ve seen attempts to promote CNG before. From the mid-1990’s to mid-2000, CNG vehicles made substantial inroads in certain niche markets and were touted as a “here-today, commercially available and road-tested solution to air quality and oil dependency problems.”
Perhaps the biggest allure for CNG was price – 20-30 percent less than gasoline and diesel fuel.
The population of CNG vehicles (mostly bi-fuel) grew from around 60,000 units in 1995 and peaked at 121,000 in 2004. While the vast majority of these vehicles were buses, pickups and vans sold to commercial and government fleets, the major automakers offered a smattering of CNG passenger cars that were available to retail consumers.
Ford offered two CNG cars, the full-size Crown Victoria and mid-size Contour. GM’s entry was the Chevrolet Cavalier, Toyota produced a CNG Camry and Chrysler offered the Dodge Caravan and Plymouth Voyager minivans.
Honda’s Civic GX (renamed Civic Natural Gas) first appeared in 1998 and is the sole GNG passenger car survivor. Through the end of November, Honda has sold more than 15,000 of the fully-powered CNG Civics since its introduction.
Despite the NGV industry’s public relations and public outreach efforts, compressed natural gas vehicles never managed to capture the public’s attention enough to drag them out of the shadows and into the spotlight. Price, around $6,000 more than the comparable gasoline model, was a huge stumbling block. Plus, the low number of public refueling stations made them impractical for most of the U.S.
The brief love affair with natural gas vehicles ended when gasoline prices plummeted and they no longer offered an economic advantage. The number of CNG vehicles operating in the U.S. decreased to just north of 105,000 in 2009.
That’s not to say that all CNG vehicles were discontinued. While the major automakers retired their CNG vehicles, aftermarket conversion companies continued operations. CNG vehicle sales have slowly increased over the past three years to about 112,000, acording to the National Gas Vehicles for America, the leading trade group for natural-gas vehicles in the U.S. The growth can be attributed to fleets comprised of buses, delivery vans, taxis, sanitation trucks and other commercial enterprises that have access to a growing number of private, central refueling operations.
Why The Renewed Interest In CNG?
Less than a decade ago, energy experts didn’t have a clue that the vast amounts of domestic natural gas resources in unconventional reservoirs like shale beds, tight sand and coal seams could be recovered economically. The predictions were that the available reserves were so low that the U.S. would have to begin importing the energy source in the form of liquid natural gas (LNG) from overseas countries such as Qatar, a sovereign Arab state.
Today we’re awash in natural gas. The U.S. Energy Information Administration (EIA) and an industry organization called the Potential Gas Committee has estimated that the U.S. holds a minimum of 100 years’ worth of proven natural gas reserves and is poised to become an exporter of the fossil fuel.
This hydrocarbon bonanza can be attributed to combining two established drilling technologies that economically release natural gas trapped in shale formations: horizontal drilling and fracking—shorthand for hydraulic fracturing.
Horizontal drilling turns wells sideways after a certain depth to open up large production areas. Fracking, which has caused strong outcries from environmentalists, is then used to loosen the shale and release gas by injection water, sand and chemicals into the well at high pressure.
This gusher of natural gas has resulted in a dramatic price fall from $15 per million British thermal units (BTUs) a few years ago to $2.00 last April. (The current price is around $3.70 per BTU.) Natural gas at $2.50 is the equivalent of a barrel of oil at around $15.
Unlike the ups and downs of gasoline and diesel, CNG pump prices stay fairly constant for months at a time. In New York, CNG costs $2.50 for a gallon gasoline equivalent (GGE). Michigan CNG stations display a price of $1.95, while in the Southwest and Gulf Coast states, 1990’s prices of $1.50 or less per GGE are common.
The nationwide average for regular gasoline is $3.39 per gallon and $4.01 for diesel, according to data from the American Automobile Association. Combine the price difference with the fact that CNG is a cleaner burning fuel and roughly 85 percent North American resourced, and it’s easy to understand the revived interest.
Where Are The CNG Cars?
This new interest, however, is currently directed towards trucks and vans.
Ford’s lineup of CNG-capable vehicles ranges from the F-250 and F-350 super duty pickups, to the Transit Connect and E-Series vans to super duty chassis cabs. General Motors began selling natural-gas-powered versions of the Chevrolet Express and GMC Savana cargo vans in late 2010, and added the Chevy Silverado and GMC Sierra heavy-duty pickups in November. Chrysler introduced a CNG Ram pickup this summer.
Global energy market research firm Pike Research in its latest report on clean energy predicts sales for natural gas vehicles to pass 3 million worldwide for the first time by 2015, with growth from the U.S. market.
Dave Hurst, senior analyst at Pike Research, said in an interview that CNG technology could see U.S. growth in the corporate and government fleets but, “I’m not very optimistic about natural gas for cars.”
His reasons for the dour forecast? First is the lack of a refueling infrastructure – of the approximate 1,000 refueling stations, only about half are open to the public. Second, CNG tank storage takes up a large space in an automobile’s trunk.
Automakers also see the CNG tank as a roadblock. At a recent industry conference, Ford’s fleet sustainability and technology manager, Jon Coleman, said customers often ask why Ford doesn’t offer a CNG passenger car.
“Functionally, it doesn’t work. Where do you put the tank?” he said. “If you have a four-passenger sedan, which passenger seat are you willing to give up so you can have a CNG-powered vehicle, or are you willing to give up the trunk?”
The tank conundrum has been addressed by 3M, yes that Post-A-Note company. 3M is close to marketing a resin-based fuel tank that uses nano-particle enhanced resins. It is lighter, holds more fuel and is less expensive than current tanks made with heavy high-strength steel.
As for the lack of refueling stations, General Electric in partnership with Chesapeake Energy Corp. has unveiled what it calls the “CNG In A Box.” Costing from $700,000 to $1.2 million – thousands less than current refueling pumps, almost everything needed is included in a 20-foot freight container. Only two pieces are shipped separately, the dispenser and motor control center.
GE has also partnered with the government’s Advanced Research Project Agency for Energy (ARPA-E) to develop a home refueling station that can do the job in less than 60 minutes and costs less than $500.
Of the three Detroit automakers, Chrysler seems the most likely candidate to offer a CNG passenger car in the near future. Sergio Marchionne, who runs both Chrysler and Fiat, has plans to integrate Fiat’s CNG expertise with Chrysler vehicles. Fiat is the market leader for natural gas vehicles in Europe, with about a 90 percent market share in Italy.
When HybridCars.com asked Reginald Modlin, Chrysler director of environment and energy, if passenger cars would be a part of CNG vehicle growth, he replied, “Our expectation is that some of those are going to be passenger cars. If the customers start buying some product, the industry’s going to be there.”
And when might we expect CNG cars from? Like all automakers, Chrysler won’t talk about specific future products and when they might become available.
The Fracking Controversy
Shale gas production has surged so rapidly that it has bolted ahead of governing regulators and public comprehension. In the mean time, fracking has become a dirty word to environmentalists who have raised concerns that it causes contamination of freshwater aquifers, increased greenhouse gases, pollution from heavy truck traffic and even earthquakes.
Fracking’s reputation hasn’t been bettered by Gasland, a 2010 Oscar-nominated documentary about the perils of shale drilling. An attention-getter for the public was footage of contaminated tap water that was lit on fire.
What’s not known by many is that methane has been seeping into poorly constructed wells for longer than a century, and igniting water from a faucet is nothing more than an old trick that causes jaw dropping amazement by onlookers, both children and adults, alike.
That doesn’t mean that the fracking picture painted by greenies is totally untrue. Improper well casings can leak chemicals or gas that seeps into drinking water and research suggests methane leaks do occur. As for earthquakes, this issue seems to originate chiefly from wastewater disposal rather than the fracturing process itself.
As the gas drilling industry has matured, these problems are being addressed and, for example, well design and construction, including the casing and cementing process, must conform to rigid state and federal regulations. High tech “green compliance” equipment captures methane and volatile organic compounds from the drilling water and prevents them from escaping. Additionally, the industry has taken the lead in recycling much of the wastewater for reuse in succeeding fracking wells.
The disdain of cheap natural gas by environmental activists goes beyond fracking – it out competes their beloved choice of energy sources, photovoltaic and wind power.
Rachel Cleetus, a senior climate economist at the Union of Concerned Scientists, said that “the problem is [natural gas] can take over the entire pie and crowd out renewables. Part of the reason this is happening is there’s a boom and there’s a sense that natural gas resources will be around forever.”
But fracking and shale gas well drilling isn’t going away. Cheap natural gas will lead to small, perhaps even moderate increases of CNG vehicles in the U.S., but its major impact is an energy source that replaces coal fired power plants, and that’s too important for the economy.
Many view natural gas as a “bridge fuel” on the road to discovering a breakthrough technology, whether that’s a cheap battery with a 300 mile driving range or, the “holy grail” of vehicle transportation – inexpensive hydrogen fuel cell vehicles.
Until then, commercial and government fleets will continue to be the major users of CNG vehicles in the U.S. That of course means most will be big pickups and vans.
But what if you want a CNG automobile? Well, you can have your present car converted to CNG at a cost of around $10,000. If you want a natural gas-powered car built by a car company, visit a Honda dealer. That’s your only choice, at least for now.
Why is a Car’s CNG Fuel Tank Located in the Trunk?
Compressed natural gas requires a larger amount of space for storage than a liquid such as gasoline. A typical CNG tank is about twice the size of the propane tank used for the gas grille on your patio or deck. Therefore there aren’t many places these cylinders can be safely installed in a vehicle. In a pickup truck, the tank usually takes up some space in the bed. In an automobile usually the only safe and allowable space large enough for the CNG tank is the car’s trunk.
A CNG tank isn’t just an air tank. The natural gas is compressed and stored in the cylinder at the U.S. standard of 3,600 pounds per square inch (PSI). At that pressure, and to meet federal safety standards, the cylindrical shape is necessary.
Of course a car manufacturer could engineer and design an all-new car with CNG tanks tucked under the body, but that’s not likely given costs to develop such tanks costs a few hundred million dollars. Or, new materials advancement could result in a free form shaped tank to replace the existing gasoline tank. But, until either of these two developments occurs, we’re stuck with less cargo space with the CNG option.