aaaah my old friend the stirling engine, how i love thee!
you can buy little desktop demonstration ones that run from the heat of your hand or a nearby candle! all it is is heat difference facilitating movement, its a very simple idea, but also a beautiful one!
you can buy one here!
http://www.thinkgeek.com/geektoys/science/9e84/?srp=1
see this link for details on how it works et cetera!
http://www.thinkgeek.com/files/stirling_...ctions.pdf
i think stirling engines will be a great post event energy system.....also this is a great thread related to energy systems
http://2012forum.com/forum/viewtopic.php?f=10&t=22642
i liked the idea about the lister engine, it sounded very do-able, and if well stocked with seeds and growing place then you should be able to produce the necessary oil in bulk easily!