So given that one of HAMs benefits is that you can stay in contact with the outside world even in a major disaster, how do you provide for emergency power to your systems?
A couple of deep cycle batteries and a few square feet of solar collector with necessary circuitry is all you need to keep a modern transceiver operational for as long as the sun shines. In receive the radio draws very little current; I've kept one dual band radio (VHF/UHF, 50 W transmitter) on a single 90A battery for more than a week (receive only).
Given that amateur radio operators have adapted and adopted a considerable amount of efficient jargon (along with retaining (CW) and developing (DIGITAL) modes more efficient than voice), transmission times are often very short. During field day a year ago I saw two radios outputting 100w each run successfully on just 3 deep cycle batteries for 24 hours and over 500 contacts for each radio. At the end of the cycle one radio could only receive but the other was transmitting in the final minutes of the event; one battery was fully discharged.
I've got an HT (Handie Talkie) that covers 3 bands and a small fold-up solar collector for charging cell phones. I've kept the radio operational for weeks checking in with friends 3-4 times a day and letting it recharge continuously.
Passing the first element (technician test) insures that the operator has enough math and science knowledge to size batteries for radio requirements but there are also a number of aids and plenty of other amateurs to offer advice. The ARRL journal QST has article on emergency power on a recurring basis; last month had a whole house and workshop system.
You might be surprised at how often amateurs are put into emergency relief. One evening last fall about a week after a particularly severe cold snap here in the SW, commercial electric power and the telephone system across the entire lower half of NM went dark. Everything from edge to edge south of about Socorro, NM, all power, telephone, 911 and OEM systems off.
Several volunteers went immediately to the main offices of emergency management in those small cities affected, set-up portable amateur radio operations and the call went out for help. Within 30 minutes more than 50 amateur radio operators were providing dispatch service for all emergency services, am information center and additional mobile operators helping to coordinate the power and 911 phone systems repairs.
The event lasted about 6 hours and except for the first 30 minutes or so, civilians in the affected area never knew the full extent of the situation. In fact when told they were in contact with amateurs while calling for fire, rescue or police assistance the comment was often "Good, someone who will do it right!". No news media made mention of the event in the days to follow. Had I not listen during most of the time of the event, I wouldn't have known either!
True to form, amateurs secured their help, the nets and those operators wishing to retire for the night and then IMMEDIATELY began a lengthy self critique. It was incredible.