The low-pressure version from Evrin is not plausible. It's fairly easy to calculate the stored energy in a given volume of compressed air, and it just doesn't give you enough to be useful even assuming 100% efficiency. Theres a lot of "might" in this article that I'm not sure how to remove within Wikipedia rules but probably shouldn't be there.

Sometimes I wonder if humanity had taken longer to understand and apply electromagnetism, could we have developed an technical civilization similar to our current one, but powered by compressed air? Instead of wires for electricity and pipes for water, houses would have two sets of pipes for water and compressed air, with home appliances powered by hose-delivered pressure. Not sure if a system like this would be scalable for a large city.

The wikipedia entry is a very general overview - IMO there's more on the possible engine types and a brief description of various manufactures who've dabbled.

A couple of decades ago iirc at least one sugar cane harvester [1] was trialled in my locale that used compressed air to power various drive trains used within the harvester. I'm also not sure but there may have even been an air powered tractor trialled as well. The main advantage would be no significant loss of fluid when a pressure line bursts -- a bug bear for hydraulic systems when the lines are deep within the machinery and oil leaks are not readily observed.

[1] Most rely on hydraulic oil, powered via hydrostatic drive system.

> This article possibly contains unsourced predictions, speculative material, or accounts of events that might not occur.

I don't think I've ever seen that before.

I wonder if this could be practically used for bicycle pedal assist. The ubiquity of gas stations with air available for free (legally required if you go inside and ask) would make refeuling very easy.