Cooley On Cars
Car Tech 101: Inside natural-gas carsNatural gas -- you can run a car on it and costs about $2 a gallon. Why are we burning anything else? A number of reasons today, maybe few or none tomorrow.
-First easy part about CNG, the part you're gonna like, all the main benefits. Number 1, cheap. Here it's about 2-1/2, a little bit more than that per gallon equivalent. Now, this is in California at a time we're paying 4.20 up to 4.70 for premium. This is a big discount. Number two, it's real clean, almost no carbon monoxide output in the exhaust and two-thirds less NOx, the stuff that really creates the nasty smog. Number three, all the bennies, tax credit. Maybe some rebates. Maybe a free HOV lane pass in your state, even a place where hybrids no longer get one. It rolls up into a little VIP club or sorts. -These incentives are very important to seeding the market, to getting these markets for clean vehicles to a tipping point where they will take off on their own. -Number four, less reliance on foreign energy. We're not a political show, so I'm not gonna dive in to that, but bottom line is America has a lot of natural gas without going anywhere to go shopping for it. Now, the challenges around CNG cars are also a foursome; storage, energy density, fueling, and combustion. First, storage, maybe it's better termed infrastructure in distribution. Your house has a costing connection to relatively low pressure natural gas source. Your car needs almost the opposite, a very occasional connection to a high pressure sort. And that's gonna require some infrastructure whether it's a pump in your house or getting to a pump that is relatively scare today. Unlike gasoline or diesel, natural gas needs to be compressed, maintained that way at filling locations like this, and maintained that way in your car; a challenge you never encounter with gasoline or diesel. CNG cars carry natural gas compressed to just 1% of its natural volume. It is really crushed down up to 3,600 psi, which leads to a possibly bulky and expensive tank and that leads us to tell us number two, which is energy density. Now compressed natural gas has somewhat less energy per a certain volume compared to gasoline or even more so compared to diesel. However, the biggest challenge around range has to do not with the density of the fuel, but how much you can carry in current car design. Partly because the cylinder design for a compressed natural gas car has to be a certain size and shape to be that strong. Remember 3,600 psi? They can make gas tanks any shape to fit them anywhere and hold even more fuel. For example, on this Honda Civic GX, which is basically the flagship of family cars that run on natural gas from the factory, you get about 250 miles out of a full, but smaller tank of compressed natural gas, versus 380 on a tank full of gasoline in the more common version. Third challenge right now is refueling. You probably haven't seen a lot of natural gas pumps at your local gas station. That's a process that's underway. In the meantime, you'll have to be carrying a guide like this that tells you where they are or using the navigation system in a car like this that will tell you where they are when you need one. Typically, these things are gonna be operated by utilities. Fleet companies, your local bus fleet for example or maybe one of the new generation of purpose built consumer refilling stations. Finally, the fourth challenge is all around this area of combustion. If you wanna run compressed natural gas in your current car, you can't. It's not like gasoline, although they share three letters. You've gotta do a fairly extensive change of the fuel metering and distribution parts within your vehicle as well as install that high-tech and smaller tank we talked about earlier. All in, it could be a 5,000- to 10,000-dollar conversion job. Well, a lot of folks you know have never done it. And once you do a CNG conversion, the car tends to be a little less of a performance car. This Civic GX for example is about 1.8 seconds slower to 60 than its gas engine sibling, although most folks who buy these cars don't buy them for dragster performance. And finally, all these combustion technology and tank technology leads to a more expensive car like most other alternative fuel vehicles. There's a 5,000, 6,000, 7,000-dollar delta that you've got to work off in cost savings on the fuel as well as whatever rebates or credits are available to you. So, here's my tech shopping list I'm watching to see where CNG cars are really gonna go. First of all, keep an eye on tank design. We talked about the hurdles in the current tank. Future designs may involve a couple of new things. First of all, multi compartment tanks that can be made of small strong compartments linked together, shaped to fit where the car really wants them that increases capacity, as does the technology that would put sort of a honeycomb, a carbon honeycomb inside the tank that has much more surface area on which to attach the compressed gas. This is all part of a Federal government bounty to create a much better, lighter, higher capacity tank for far less money that can get around these expensive cylinders we're dealing with now. Next, I'm watching home CNG compressor design, in other words, a filling station for your home. You can get these today. They cost 3,000, 4,000 dollars, another 3,000 to install, most folks aren't gonna be able to swing that. The government's got another bounty program out there saying, look, who can be the first to bring a 500-dollar home compressor fueling station on the market that'll get the job done easily overnight from your low pressure home source. Then there's fuel cost, again not my expertise, but the idea that there's a big delta between natural gas and gasoline is key to the appeal of these vehicles. Finally, fuel sustainability. Right now, we get most of our natural gas out of sources that are prehistoric and are finite. Going forward, there's auto research being done into getting biomethane, methane that is coming from sorts of waste we create all the time in other avenues of life.