You've probably heard of the - too - famous air car and its equally famous compressed air engine, probably through the media.
Since 1996, many reports and articles are devoted regularly to revive the, ultimately, false good idea of the air motor.
Indeed, the overall return on the primary energy of compressed air can only be bad (all air manufacturers will tell you) whether this is compared to a thermal car but also compared to electric cars which, themselves, still pose many problems and disadvantages. However, the air car “competes” directly with the electric car (small “clean” urban trips).
The use of compressed air should, in our opinion, be limited to the recovery of braking energy with a completely independent on-board system with main electric or thermal propulsion. That is to say that we should not be able to recharge with air: the autonomy of the tanks is limited to a few decelerations or accelerations (ie, at most, a few hundred kJ) ...
The situation would obviously be different if the air was compressed by renewable energy sources, but renewable energies are already lacking so wasting green energy by compressing air is it really wise?
In 2003, the Ecole des Mines de Paris carried out 2 studies on propulsion by compressed air, you can download here. It is interesting, or rather appalling, to hear from MDI, the company which developed this air motor, that they do not know these 2 reports.
To better understand the phenomenon of the "air car", here is a Investigation Complementary Investigation Video broadcast a few days ago.