All the hot air about the MDI air car may experience a sudden cold downdraft. Not that cool breezes questioning its efficiency weren’t already wafting in the air. But now there’s a genuine academic study questioning the questionable. The NYTWheels has mined a study by the University of California at Berkeley titled “The Economic and Environmental Evaluation of Compressed-Air Cars,” which concludes that the air car “fared worse than the battery-electric vehicle in primary energy required, greenhouse gas emissions and life-cycle costs, even under very optimistic assumptions about performance. Compressed-air-energy storage is a relatively inefficient technology at the scale of individual cars and would add additional greenhouse gas emissions with the current electricity mix.”
Andrew Papson, a member of the team that published the paper, elaborates:
“Compressed-air cars sound very nice, and they share with electric cars the advantage of not producing any local air pollution on the road, as well as being able to charge from the grid, but electric cars are much more efficient,”
Felix Creutzig, a co-author and post-doctoral fellow, offers this bottom-line assessment:
“Electric cars are about three times more efficient than compressed-air cars.”
Compressed air holds less than 1% of the energy of gasoline, and based on specifications he obtained from M.D.I., the air car would have a range of some 29 miles. The report’s conclusion is that air cars are “ultimately not viable, comparing poorly to gasoline and electric vehicles in all environmental and economic metrics.”
Too bad; we could use a little more hot air in these parts right about now.
“Electric cars are about three times more efficient than compressed-air cars.”
So what? Electric cars are also about three times more efficient than gasoline cars.
I’m not a big believer in compressed-air cars. But this posting makes them sound like a scam. They are not. Whether they will succeed or not is, of course, a different question. But they are a legitimate technology.
I can’t really believe that anyone actually thought that air cars would work. In order to create enough energy to power a car for any range, the air tank would have to be huge, and hold an awful lot of pressure. Just ridiculous.
I’m a strong believer that this article is a bunch of B.S. Or more specifically, oil-industry-speak. Indian auto maker, TaTa Motors has many orders backed up for a compressed air car that they build. London is waiting for 500 taxis. It will run for up 300 miles on one filling of the carbonfibre tank. The compressor comes with the vehicle and you install it in your garage. It runs on your local household current.
At the senate hearings that the auto industry chiefs flew corporate jets in to Washigngton, Rick Wagner, CEO of GM, told the commission he never heard of a compressed air car. Not only did lie, he had seen it. TaTa builds GM cars for India a number of surrounding countries. Exxon has tried to buy the patents with no luck.
Yes, there is a compressed air car in our future. Do not fall for the oil-speak BS.
Why would the oil industry care whether compressed-air cars are more or less efficient than battery-electrics?
You got any evidence for any of that amazing rant?
In particular your claim of 300 miles range?
In particular any evidence that Tata has a production line for aircars?
Or has sold even one to a normal customer?
They are trying like crazy to discredit the air car. It’s a threat.
They needed to study that compressed air is less efficient than batteries? non-adiabatic (since we will lose the heat in such small cylinder… utility scale compressed air can be adiabatic and keep the heat of compressions and reuse it) compressed storage is 50% efficient in theory (and less in practice..). Batteries are 80%+ efficient. Any thermodynamics professor (or anyone who is able to use Google) could have told you that.
So, now pay me the money you paid the people who did the study. I provided you the same information :-)
I’m too lazy to compare energy density now..
It always amazes me how they have new studies (possibly paid for by me) that have conclusions like “smoking teenagers more likely to get retarded babies” “eating fast food makes fat and is unhealthy”… you’d think so? Or other Wisdoms I learned in the 5th grade back in 1985 and now they sell it as cutting edge study?
I am not going to say there is no slot for the air car. However, I can fully agree with the efficiency analysis. Anyone with a aircompressor would concur.
Compressing air is a very inefficient process, generates lots of heat during the compression stage. So much heat in fact, you can’t touch most of the active parts of any a small home garage compressor for up to 5 minutes after the target pressure is hit and the motor is switched off. Compressing air just sucks.
On the other hand, compressed air holds a lot of energy. Air tools rarely suffer from performance problems when compared to electrics, and they don’t have that sparking problem to deal with either.
So if you are going air car to stop global warming: bzzzt. You just lost. If you are going air car because electricity is cheap where you are and there are no gas stations, then sure, go for it. Just make sure the local grid can handle loads of very inefficient compressors driven by a induction motor (they have terrible power factors when they start, and they make a lot of racket, the power factor serving to further reduce the efficiency of the compression system), you know, when everybody in your community buys one!
I will leave the efficiency of stand-alone air power to be beaten about. It’s a distraction.
The real practical application for compressed air is in the form of a hybrid. Navy labs built a YuSuburbaHo pneu hybrid many years ago. Very simple, cheap, and city mileage went to the low 20’s.
There’s a huge industry invested in battery/electric hybrids, but pneu is cheaper and just as effective in a stop-go urban scenario.
Um… careful here. Let’s not give air compression a bad name. Then idiots will shy away from any thing that might have it.. such as compressed air hybrids.
I wish I had a small air tank in my car that used engine compression to trap air during breaking, and then fed it back in again when accelerating. That function is where electric hybrids get a very large chunk of their fuel efficiency. However, overall the system is much more efficient than electric hybrids because it is so, so much simpler, lighter and cheaper, and more environmentally friendly.
But it’s not an electric gadget and this is the e-gadget age. Sigh.
BTW there are many types of air compression & release systems, and their efficiency varies. Some use turbines, much more efficient than the diaphragm or piston-based pumps.
But yes, a car powered entirely by air would have to be dangerously light and top-speed limited to achieve any useful range. But in some countries, light and slow is way better than walking.
<A HREF=”http://spectrum.ieee.org/energy/environment/deflating-the-air-car”>Peter Fairley in IEEE Specturm</A> also has a good article on why the air car claims don’t add up. He ran the numbers from the manufacturer’s claims and they didn’t make sense.
If only all the verbal “output” from politicians everywhere could be harnessed, then this concept might have a future.
Hey, if you mount a wind-powered propeller (turbine to be fancy) on the car roof, you can use the wind power going forward to power the air compressor to run the motor to drive you forward.
Zero-emissions.
Eliminate importing foreign oil.
Stop funding terrorists !
Just give me a couple million dollars to work the kinks out…
in a cordage mill dating back to the 1830s , starting about 1878, a compressed air powered indoor locomotive was used to haul material in from the piers. It was in service for 70yrs
Well, it’s obviously not the silver bullet everybody is looking for. Just as hybrids use electricity and an ICE to bypass the battery limitations, maybe compressed air technology needs a companion under the hood to provide those much admired “synergies” executives are always talking about. I propose mating this contraption to a stirling engine. You backyard mechanics get to work! Fame and fortune await.
You guys can laugh all you want to, but the compressed air engine from MDI is already on the road. No, it is not a hybrid.
http://www.mdi.lu/english/produits.php
You engineering types are proving that as you are learning more and more about less and less until you know absolutely everything about nothing.
http://www.mdi.lu/english/produits.php
Us engineering types have persuaded MDI that a pure aircar is a waste of time, that is why Negre is going to a compressed air hybrid. As tot he rest of your amazing claims, bear in mind that nobody outside the company has been allowed to measure the range of one. Nobody.