Generators for generation of electrical power 

Generators  can provide warmth and comfort when operating, and in the case of the unprepared make a difference between survival and non-survival almost instantly.  They are a highly desired piece of equipment with high trade value.  Naturally, this tends to make the owners targets of those who are without.   The commodity value is high enough that others may take significant risks to procure your generator.   This is definitely a consideration. 

Generators are also noisy, extremely valuable as long as their is a sufficient fuel supply.  Despite this they tend to attract attention so selecting when and where to use one may be a factor.

A generator is both a huge potential asset and a potentially huge liability.   Consider this piece of equipment carefully.  Generators tend to be expensive and are almost always bulky.  The bigger the generator the greater the fuel demands and energy output.   As a rule of thumb, larger generators also tend to be nosier and attract a greater amount of attention.   Of course if you are the only individual with operating utilities in the area, you are likely to generate a significant interest.  This can be the center of a community, a personal treasure or a huge target.

Generators are be powered by diesel, gasoline or propane.  Combustable fuels which release tremendous amounts of energy when burned.