My thoughts on stand-by power.
When generating electrical power, it is very expensive no matter how you do it. 10X the cost of what you purchase from the power grid, especially if you use fuel that includes road taxes. I have found that fuel consumption equals how much/how many watts you are using. When I loose power I can figure that it will cost me $40 - $60 dollars a day for gasoline. My grid power cost about $4.00 a day. I'm thinking that generating my own electrical power is only 10% as efficient as grid power.
My thought is to reduce my electrical needs by installing propane to heat water, cook and heat when needed instead of generating my own electric for these things. I feel that I could get my minimum electrical need down to 2 or 3 kilowatts which I could do with a small diesel or propane generator. Propane would be most reasonable if I cooked, heated water and heated with propane because I would have a storage tank already. Of course if I had natural gas that would even be better. This way I would not be paying 10X the power cost to operate these high energy use appliances. Also with an inverter I could operate lights and a TV or computer for a few hours at night on batteries.
Of course, if you are running a farm then get out the tractor and hook up the generator and go feed and milk the cows.
I forgot maintenance and equipment are a big cost also..