[Xellos-_^]

A growing body of opinion seems to think liquid air is the answer (or, more specifically, the nitrogen component that makes up 78% of air). It is not exactly a new idea. Air was first liquefied in 1883, using essentially the same process as today—ie, compressing it to 200 atmospheres, cooling it to -190ºC, and then letting it suddenly expand and condense. The process turns 1,000 litres of transparent gas into 1.4 litres of light blue liquid.

As long as its storage container is well insulated, liquid air can be kept at atmospheric pressure for long periods. But on exposure to room temperature, it will instantly boil and revert back to its gaseous state. In the process, it expands 700-fold—providing the wherewithal to operate a piston engine or a turbine.

Liquid nitrogen does an even better job. Being considerably denser than liquid air, it can store more energy per unit volume, allowing cars to travel further on a tankful of the stuff. Weight for weight, liquid nitrogen packs much the same energy as the lithium-ion batteries used in laptops, mobile phones and electric cars. In terms of performance and range, then, a nitrogen vehicle is similar to an electric vehicle rather than a conventional one.

http://www.economist.com/blogs/babba...nitrogen-cycle

any experts care to comment?