Re: Atmosphere
True, though in this context, presumably you're not getting it by cracking locally-drilled petroleum. Whatever your power source, hydrolysis of water into H2 & O2 is going to be a very handy portable chemical energy system, assuming technologies for safe transport of adequate H2 supplies are developed.
The real advantage of chemical energy is that it's got a high power-to-weight ratio for devices at the low-weight end of the scale (which means that for short-duration medium-power output, chemical devices are really good) and it has a modest start-up cost. Think weapon cartridges here. Even if personal laser pistols were to become the sidearm of choice, I suspect handguns would still go "bang", because chemical lasers still have about the highest power per gram of device; so instead of a guncotton-filled ball cartridge (eaching firing once and then getting ejected) it'd be firing off premanufactured chemical laser cavities (which also would fire once and get ejected) giving you extremely high-energy pulses. Similarly, for short-haul vehicles too small to have a sustained reactor or other megascale power plant, filling up the tank as needed with some chemical fuel is going to be the operation mode of choice.
Generation of AC electrical current on a large scale -- that is, the colony's primary power -- has to be done from some other class of source on a space colony, because chemical energy has a really awful power-to-weight at the high end of the weight scale.