I have always advocated keeping a couple tons of coal on hand - even though I have none myself at present. It is bug free, can be stored out doors, in a pit, in a swamp, in your living room, basement, or any handy location. It doesn't spoil if it gets wet, it doesn't rot, it doesn't evaporate, and you get a lot of energy for your money. You can heat your home with it, cook your food with it, and in a pinch you can grind it into powder to mix with sulfur and saltpeter to make gun powder.
If you want to store it covertly, use it for mulch in your flower beds around your home. Hell, you can use it instead of gravel for your driveway. Be creative.
Woody