Switching gas fireplace from utilities to a bottle?

I am connected to city natural gas, but the only appliance in my home that uses it is the gas fireplace. Since we’d only use that about three or four times a year I don’t want to pay the $5 monthly fee that the utilities company charges. The result is that the fireplace sits dormant because I don’t have the gas turned on.

So is there a way to hook this system to a bottle, then just fill the bottle with propane or natural gas and use it when I want to have a fire and never turn on the utilities?