I don't know if everyone does this, but we do not pour grease down the drain. It can clog your drains and makes a particularly nasty clog when it happens. So, you save a large glass jar and dump your grease in there. Once it is full, put the (saved) lid back on and toss it in the trash. Okay, this is all common knowledge, right?
Last night we were watching a cooking show about a place in Chicago, famous for its 72 day-old aged steaks. In one part of the show, guests were served a sea-scallop appetizer and the head waiter came out with a votive candle and dripped molten wax onto the dish! He quickly explained that the "candle" was actually bacon grease and so this was a seasoning for the scallop. Most of the "candle" looked to be quite solid and I suspect that it was actually rendered beef fat, which in my experience is more solid at room temperature than bacon grease. Also, earlier in the same show, they had talked about rendering the beef trimmings and using this, as they called it "beef love", to season their steaks.
I forgot all about that show by this morning--until I went to dump the morning's bacon grease into the jar. I had to try it. I mean, anybody who had just seen that show would try it, right? Yes. Of course they would and I would too. And did.
I put a small length of cotton string into the grease and lit-er-up. This resulted in a clear, non-smoky and (possibly) odorless flame. I only say possibly because there was already bacon smell in the air, plus just the open jar smells a little bit.
So if you have a power outage and no candles, or the outage outlasts your supply of candles; you have another way of making light.