It sounds like a good idea: Use electricity to compress air, stuff it in a tank and use the power expelled by the air’s release to power a vehicle. Seems like a good idea, certainly a lot easier to understand than nano-constructed cathodes on a lithium ion cell. And several companies have been actively attempting to build cars powered by air compressors for quite some time. We at EcoGeek have been excited about them. The two biggest of these companies are MDI, a French company and Tata Motors, India’s largest car company.

The end of compressed air cars

But I have bad news. Today, here at EcoGeek, we are declaring the air car dead. It’s a question of physics, every conversion from one type of energy to another decreases efficiency. With battery electric vehicles, energy is converted into electricity and electricity is converted to motion. With air cars, energy is converted into electricity, electricity into compressed air and then compressed air into motion. Because of this, compressed air cars will always be less efficient than electric vehicles.

Even more problematic, no air car has ever been developed that can reach highway speeds and no air car has even been demonstrated to have a range of more than 10 kilometers. Promises were made, and with the entrance of Tata Motors to the fray, we thought there might be some truth to the claims.

But Tata’s goal of a 2008 release of an air car has, obviously, not been met. In 2009, Tata stated that the short range of the cars and issues with keeping them from freezing up (when compressed air is decompressed, temperatures drop dramatically) were proving them impractical.

So, I’m sorry my friends, we’re all going to have to be happy with the much more technologically confusing (though also much more efficient) battery electric vehicles. The good news is, with the Leaf and the Volt already hitting the road, that’s one technology that definitely isn’t vaporware.