If all else fails...
Get a car battery, preferably a sealed one, or a big(ish) sealed gel battery and an inverter. The only other thing to watch out for is the inverter type. Cheap ones are not pure sinewave output, which may cause problems with some equipment. Pure sine inverters are easy enough to get hold of, just that they are more expensive.
What ever you do, do not do this !
Ask your local engineers about Noise ! not the aural kind, Chinook especially.