A) Piped natural gas is highly reliable here in the East. I've
not had such in 10+ years. An even-momentary outage is cause
for great alarm (and media coverage) since they can't restart
the line without visiting every residence, closing the shutoff,
only then re-starting the line, and visiting every residence to
re-light pilots, & run a nose-check. (Dirty little secret of old
black steel lines is they rust from the inside; but then don't leak
much since the line pressure holds the flakes in place. But drop
line pressure, they deflake and it's swiss cheese when restarted.)
I infer the req'd earthquake valves in Califunny also close on
line pressure failure; so you can restore the line without a
shutdown visit first?
B) I know of no good way to store natural gas on-site. The utility
typically uses an underground cavern that was a salt dome and
hollowed out with lotsa H2O.
Compressing gas locally is even less likely; it takes real KW to
run the compressor station, as well as a safety zone surrounding.
C) Yes, you CAN store propane, a different product. But if you
need a lot of fuel, errr. A big propane tank is 300 gallons. I
suspect the Fire Marshall will take intense interest in storage
near a building of any size, much less in.
Propane is heavier than air. Some codes ban its use in a basement
without positive ventilation, gas detectors etc.
D) Diesel engines, err Diesel-fueled piston engines, be they 2
or 4-cycle, need frequent oil changes. I have every reason to
think natural gas/propane fuel would require same less often;
the washdown of such will evaporate out unlike #2 diesel.
But I've been wrong before.
E) There are "dual fuel" diesel engines; maybe several kinds.
I've read of the ones at sewage plants that suck ...methane
vapor... from the digester tanks; not only is it "free" but
the stink burns with it. There are also natgas/propane/gasoline
generators in the ~10KW size, but that's spark ignition.
By the ways:
1) "We don't mind dumb questions; they're easier to handle than
dumb mistakes.." is the sign on a friend's machine shop.
I applaud the OP for being willing to ask.
2) At least pre-Ashcroft, the cops need a warrant, or probable
cause, to haul you off. At least in most states, the Fire Marshall
He can show up unannounced, throw you out, pull the main breakers
and shut all the fuel valves. He leaves a red tag on the door
and you are out of business.
Especially post 7 WTC and West Warwick; I'd not expect lots of
latitude from your local/state fire inspector.