Fuel isn’t as big a problem as you might think, at least for the 30 days that we’re planning for. A Honda 2-3kw will use less than ½ gallon per day (assuming you only run it for an hour/day to charge your power cells), meaning you’ll need 15 gallons/month. If you cook using a propane grill a 20-pound tank ($30) will give you about 12 hours of cooking, so 2-3 tanks should be enough. If you chose to use the common 14,000 BTU Coleman camp stove the tank will last for 2 hours running both burners on high, so you’ll need only 5-6 gallons of lead-free fuel or Coleman white gas to last the month. Whatever generator or cooking method you opt for, try them out before you need them to make sure they work, and determine the REAL fuel consumption rate. Then plan accordingly.
Gasoline can be difficult to store for long periods of time because without chemical stabilizers, it becomes useless after about a year. Rather than store fuel, try to rotate it by consuming it in your lawn equipment or vehicle. I have three 5-gallon containers that I store and rotate into my mower. Every 6 months I use them in my car and refill the cans with fresh fuel. If you intend to use a gasoline powered stove for cooking, consider storing a gallon or two of “white gas” or “camp fuel”. It is expensive ($6/gallon @ Walmart) but is stable to store and odorless. Even though its expensive I use it because I don’t like the smell of gasoline around my food. I’ll use gasoline in a pinch, but given the option prefer white gas.
Your car is a reservoir of gasoline sitting in your driveway. A good habit is to fill your car before it gets below ¼ tank, thus insuring you have at least some gas to tap into if an unexpected emergency pops up. If the event is announced, as in an approaching storm, try to fill your tank even if you don’t intend to evacuate. Not only does it keep your options open to evacuate later, but you’ll have about 20 gallons of fresh gasoline sitting in your driveway. Most modern cars have an anti-siphon system in the fuel line to prevent gas from flowing out in a roll-over. The way around this is fairly simple. Use a stiff ¼” plastic hose (like the one on your ice maker), cut one end at a sharp angle and insert it with a screwing motion. It’ll eventually work itself past the anti-siphon ball and into the tank. You’ll know its deep enough when you blow into the tube and hear bubbling sounds. Begin siphoning but expect it to take 10 minutes or more per gallon through that narrow tube. A more drastic method is to drill a hole in the lowest part of the fuel tank and catch the gas with pans. If you do this, make sure you have enough pans and containers to transfer and store the gas. When the tank is empty it’s easy to fix with a self-sealing screw.
The most common BBQ propane container is the 20-pound tank, which holds 4.6 gallons of liquid propane (375,000 BTU) and weighs 37 pounds when full. Most full-size BBQ grill burners produce about 30,000 BTU, meaning a 20-pound tank can run for 12 hours. Tanks also come in 5, 7, and 11-pound sizes that may be more convenient if you have trouble lifting the larger size. If you prefer a stove other than the Coleman, there are small 1-pound cannisters containing 22,000 BTUs of energy, meaning a backpacking stove producing 5500 BTU can run for four hours. Assuming each meal takes no more than 30 minutes to prepare, it should last about 8-10 meals. Calculating it out, you’ll need roughly ten of the 1-pound cannisters to get through a month-long event. Using 20-pound tanks you’ll need only two per month.