I want to say a little about burning fossil fuels for heat. We really dodged a bullet in 2008 when that big hurricane-related wind storm knocked power out to tens of thousands here in the Dayton area -- we were lucky it was summer and not winter. I know many people who were out of power for 2 weeks. What would you do for heat if this happened in the winter? For some of us, the answer is a fireplace or wood stove. For others, the answer is: I'd freeze.
Open fireplaces, with doors or screens, can provide some heat but they are highly inefficient. They burn wood faster due to a high volume of oxygen sweeping past the fire, carrying much of the heat right out the top of your chimney. If you have an electric blower on your fireplace, it's a shade or two better, as it sends some of the heat into the room.
The wood stove is a much, much better choice. Usually the metal firebox extends at least partially into the room, providing radiant heat (and a burn risk), but they often have built in blowers which can really burn you out of your house. Most have catalytic converters which can be engaged once the stove reaches a high enough temperature which futher enhances the stove's efficiency, burning less wood, and burning the fuel more completely.
Both of these options, though, except the open fireplace, require electricity to run the blower. Radiant heat will still provide heat, but the really good heat will be lost if you can't blow it into the room. Also, some fireboxes require that the fan be blowing or it can damage the stove due to overheating (look to your manufacturer if you are concerned about this). So how do you get electricity? My solution is a large battery. There are many companies which sell these. Some are referred to (somewhat incorrectly) as "solar generators". A battery is a means to store power -- not make it. My choice is Goal Zero. (Yes, we have these at the store to look at.) It's a large battery you keep topped off by plugging into the wall every few months, so that it's ready to go when you need it. Couple this with a solar panel and when the power is out, the sun keeps topping the battery off enough to keep the blower going.
A small generator is also a useful tool. The generator can be used to replenish a battery such as the one described above, to run a blower directly, OR, if you're lucky enough to be on natural gas, to be plumbed into your furnace's air circulator (fan) so that your home's heat still works. Natural gas continues to flow after the power is out, however, your furnace will not circulate the air during a power outage, as that runs on electricity. The fan doesn't take much power, so even a small generator will run that for you -- not to mention giving you a few extra circuits for lights, charging, or whatever else.
In addition to burning wood, if that is not in your future, there is always oil derivatives such as kerosene. Double check my advice, and ALWAYS have carbon monoxide and smoke detectors in ANY room that burns fossil fuels; that said, cracking a window just a few inches in an enclosed space is usually enough to circulate enough air through to allow the safe operation of a kerosene heater. Hang a few curtains over door ways, or close doors to block off a small area, and you've got decent heat.
Small propane powered devices, like "Mr.Heeter" or similar device, are also a good solution for low cost, effective, and generally safe heat. Many of these devices now come with built in carbon monoxide detectors and tip-over switches which will automatically disable the device if there is a problem.
Whenever a heat source is producing, a great way to "save" some of that heat is to place conductors nearby. A large cinderblock, bricks, even ceramic pots or any derivation or combination of such materials, if set close to a heat source will absorb the heat and continue to emit that heat long after the flame goes out. Rocks can even be used (make sure they have not been in or near water for many many years, as river rocks can explode when heated). If you cover these heat savers carefully, you can even put them in the bottom of a sleeping bag, or under the covers of a bed to provide extra heat there.
So there are some possible solutions for heat during a power outage. PLEASE EXERCISE CAUTION WHEN DEALING WITH FOSSIL FUELS. This discourse is not an approved course of action from a fire marshall, but rather the account of one individual -- check and double check all information and examine all possible safety concerns for yourself.