I used to have one of those in my 5th wheel trailer, although mine used propane.
We were buying a gas stove and I saw they had natural gas refrigerators. They were about the same price as the electric refrigerator I was looking at and the power does go out around here three or four times a year. Since we were having gas lines run anyway I decided to go for it. I would say it costs about 40% less to run than the old one.