Can Natural Gas Cars Replace Gasoline Cars?

We hear a lot about Electric cars, but very little media coverage on the CNG alternatives. Is the problem with creating an infrastructure of filling stations? Is it hard for existing gas stations to offer CNG in addition to unleaded and diesel? Would a CNG pump work as fast as a gasoline pump?

I already have natural gas supplied to my home. What I’d like to do is fuel up my car in my garage with cheaper (per gasoline equivalent gallons) natural gas and pay for it out of my monthly gas bill. Is the technology possible to standardize and mass produce home fueling stations that are safe?

What are the expensive pain points that prevents widespread adoption? There must be a sticking point that is keeping the grass roots adopters low.

Wikipedia seems to indicate the sticking point is the type certificate. If the US Govt. was on board, can we solve the $50,000 type certificate problem?

Would you own and drive a CNG car if they became widespread and available? (Assume fuel cost savings of 30-60%)

There certainly are LPG cars, not Natural Gas ones that I’m aware of. In what way is the OP claiming they would be better?

The upside of electric cars is they are not tied to a particular method of power generation; once we have a suitable mix and methods of renewable power generation nothing will have to change with the cars themselves, whereas car that were build to be fueled by natural gas alone are tied to that power source, and its consequent carbon dioxide generation (around 1/3 of petrol/coal sources, which is preferable but not sustainable).

My gas stove and gas dryer are tied to that power source. If there’s a problem with my natural gas supply, I’d have to buy a new stove, dryer and water heater.

Is there something special about cars that one might be especially concerned if they are tied to natural gas?

Is it that hard? No harder than offering fast charge for electric cars. In both cases the issue is that the infrastructure sufficient to support distance travel won’t be built before the cars are on the road. The infrastructure for charging an EV overnight at home is easy and the one for a natural gas car a bit more difficult - Honda owned a company that made one called Phill but that company went kaput. Now Honda, the only company currently selling a NGV to the mass market, advises finding a fast fill location, and there are not too many of those that have public access, about 500 in the whole country. So you are left with it only making sense for fleet vehicles that can create their own fueling site and very few others.

Natural gas would also be more efficiently used to power a plant to produce electricity and use that electricity to power a vehicle than using it directly in the vehicle.

Finally natural gas has a few good decades before it starts getting in short supply. EVs OTOH can continue to be used no matter resource is most cost effective to use to produce the electricity (natural gas, nuclear, a renewable, etc.).

That said, some incentives may be in the works.

The trouble with it is just that none of the advantages CNG has are particularly compelling these days. When CNG and LPG conversions were popular in the wake of the 70’s energy crisis, natural gas was much cheaper than gasoline, but now the price differential has narrowed significantly, especially when a road tax is applied. These days the cost differential just about cancels out the lower mileage, depending on what gas prices are doing. The gasoline engine has also hugely improved since those days, so the air quality and reduced maintenance advantages natural gas had are much less compelling now.

The other issue is that conversions are much harder. Back in the 70’s, you could buy conversion kits out of the mail and any reasonably skilled tinkerer could bolt it on to a regular old carbureted engine. These days though, CNG kits have to be integrated with fuel injection and emission control systems, as well as be certified to meet the various safety and emissions regulations, so professional conversions are really the only way to go.

The issue with the certification fees is that the companies doing the conversions need to certify their installations for a particular application. I think that is only a stumbling block to making lots of small volume kits. In other words, if they were selling large numbers of the kits, the $50,000 wouldn’t be an issue because they could spread the cost, but if they made a conversion for a model where they only expected to sell a few dozen, that would be a problem. But it’s an issue of the fee being a problem because the conversions aren’t popular, not the conversions being unpopular because of the fee.

They did it in Dad’s Army. Didn’t go well.

I had an email exchange a couple of years ago with my dad and brother regarding CNG (compressed natural gas) vehicles. Here’s what I wrote them.

Did a bit of digging on CNG cars. Found this page on the Consumer Reports website that summarizes things pretty nicely.

I also went digging on Honda’s website. The Honda Civic CNG is currently the only production CNG vehicle available in the US. A comparison with the non-CNG version of the Civic is instructive:

The CNG Civic sells for $25,190 ($4,000 federal tax credit leaves owner with final cost of $21,190)

24/36 MPG, city/highway
8 “gasoline-gallon-equivalent” tank capacity, for 290-mile highway range

The Civic-LX (the trim package most similar to the CNG version) sells for $18,255

26/34 MPG, city/highway
13.2-gallon tank capacity, for 450-mile range

For privately-owned vehicles filling up at retail gas stations, the price difference between gasoline and CNG historically hasn’t been very large. Yahoo says that in 2006 the per-gallon price difference was only 24 cents. Gasoline went a little crazy in 2008 of course, but given that gasoline is back down to 2006 prices, I’d bet we’re back to a 24-cent-per-gallon delta again. You’d have to buy over 12,000 gallons of fuel (and drive 440,000 highway miles) to recover the $2900 difference in purchase price between the two vehicles.

You can can drastically reduce your CNG cost by buying a home CNG filling station that takes CNG from your house at a much lower cost than what you pay at a retail gas station. The two big disadvantages with this are the cost ($5,500 to buy/install the Phill system in your garage), and the fill time (the system has to pump CNG up to 3600 psi to stuff it into your car’s tank, which literally requires overnight-filling). I don’t know how much CNG costs from your house’s line, but even if it were absolutely free, you’d have to drive almost 200,000 miles to recover the cost of the Phill system. That’s on top of the 440,000 miles you already have to drive to recover the vehicle’s price premium.

While there are environmental and foreign-policy advanages that come with CNG vehicles, clearly it currently does not make any economic sense at all for a private vehicle owner to buy a CNG vehicle. Other turnoffs:

  • the average joe’s fear of CNG (despite its actual safety advantages over gasoline);

-range anxiety (we can argue about its rationality, but rightly or wrongly, this anxiety does exist for many drivers);

-the CNG tank sits in the trunk, where it substantially reduces cargo capacity; and

-the only production CNG vehicle is the Honda Civic. If buying American cars is important, then CNG (in an out-the-door production vehicle) will not be an option.

-extremely limited availabiltiy of CNG at retail gas stations.

CNG vehicles are popular with fleet owners because the cost of their own private filling system gets distributed over their entire fleet. With cheap CNG available on site, fleet vehicle purchase-price discounts, and a fleet that quickly racks up miles, they can recover a CNG vehicle’s purchase premium in a reasonable time frame.

Aftermarket CNG conversion kits are available for virtually any vehicle (see ), but they’re not cheap either. a conversion kit, including installation, runs about $3000 for a 4 or 6-cylinder engine. Note that this is pretty much the price difference between the CNG and gasoline versions of the Honda Civic, so you’re back to driving astronomical distances to recover that cost. The company at the above link does offer fleet conversion discounts, which again helps to explain the popularity of CNG in fleet vehicles.

In the end, you’ll have to see a very large increase in gasoline prices (or a major shift in consumers’ environmental/foreign-policy sensibilities) before CNG becomes popular with the masses.

A new car is is easily ten times more expensive than those three appliances put together, so replacing it if natural gas supplies become an issue is more difficult. It is also probably easier for most people to get by without natural gas appliances than without a car - one can hang up laundry, get a electric space heater, sponge bath themselves with cold water, and cook with a microwave or electric griddle, at least for a while, but many people need a car to get back and forth to work, and live in an area where bicycling or taking public transport is impractical.

Switching a large number of cars to natural gas will also cause those reserves to be drawn down more quickly, as the fuel people use in their cars can easily be more than they need to heat their house.

Thanks for the great responses. Good info!

FWIW, Chrysler/Fiat has, in the past few weeks, made it clear that they willnot be committing much to EVs for now and will instead try to carve out a niche in the natural gas vehiclemarket.

Really excellent info, but I think your logic/math is slightly off here. The 440k miles was at the retail price differential. If $5k for the filling station equates to 200k miles, then the 2.9k price differential should be another 120k miles, not 440k. Of course, that’s assuming “free” natural gas, so the conclusion, that it’s just not worth it, still holds.

Back in the 90’s I had a client that was very into CNG vehicles and pushing hard to break them out of the fleet category and into general use. They almost had a deal signed with one of the Detroit manufacturers when the auto company made a simple request: the converted vehicle had to go 200 miles (with a certain safety margin) on a single filling.

They couldn’t modify a vehicle to do it, at least not without the fuel tank taking up virtually the entire trunk.

You can argue that a 200-mile range isn’t necessary (it certainly isn’t with delivery vehicles and the like) but the auto manufacturer argued back that the natural audience for a CNG car would be high-mileage users, and, given the difficulty of finding a fast-recharge station and the amount of time it takes to refill the tank, 200 miles was the minimum they could ask a driver to go without worrying about a refill.

I know at that time, Ford, GM, Chrysler and several European/Asian manufacturers were seriously interested in CNG, but most of them ended up certifying independent aftermarket converters and not getting into the market themselves.

At the company I work for, the target is 400 miles per fill-up, pure electric vehicles aside.

I know. A 400-mile range for a gasoline or diesel powered vehicle is nothing, so simply asking for 200 miles from a CNG vehicle was a MAJOR concession by the automaker.

UK-side, LPG is running about 40% cheaper than unleaded, which by my math works out at about 7p per mile saving. At £7 per hundred miles, it’s not hard to save £100 per month, which is going to make back the cost of the conversion in about 15 months. Availability’s not great but it’s doable.

Of course, if a lot of people converted their cars, more gas stations would offer natural gas. Until your government decided to raise taxes on natural gas, to match the revenue lost from petrol taxes. (Those trains & subways don’t pay for themselves, you know.)

Yeah, I’m basically saying “Pull up the ladder, Jack, I’m aboard” on that one (or at any rate Mrs M is, though we may convert the other vehicle if I look like doing enough miles to make it pay). At least for now there are few enough people using LPG that the differential looks like lasting for a while. As to the taxes, sadly I’m not too sure, nor are many other Brits, that the revenue raised from transport gets spent on transport - the gubmint seems to have plenty else to spend our money on.

the economics aside, it’s quite possible since it can be burned in the same spark-ignition engines that already exist. it also has the benefits of an approximately 130 octane rating, so it could be beneficial to the trend of using smaller forced-induction engines. Further, it’s gaseous so you don’t have the fuel contamination of the motor oil that you can have with gasoline (though you still have to deal with the water production of combustion.)

Downsides, of course, are the availability and lower energy content vis-a-vis gasoline.