Comments

The numbers I used above for energy efficiency were what I remembered from my energy conversion class from school. But from looking at the wikipedia entry for ICE's they have a good section on their energy efficiencies. From there it looks like they are around 20% with a thermodynamic limit of 37%. From a quick web search it looks like I was off on the power plant efficiencies as well. It looks like they vary between Fuel Oil at about 40% to CCGT(gas) at about 60%. Its also a good idea to separate energy efficiency from pollution when thinking about this stuff. High efficiency does not mean less pollution, it just means it uses more of the power available. So your LP genny may pollute much less than a coal plant but that is unrelated to its efficiency. I think its great you are using renewables exclusivly, and I agree about hydro (although each type of power generation is a trade of in some way, none are perfect).