Energy Density
MaterialBy Volume   By Mass
Diesel Fuel10,700 Wh/l12,700 Wh/kg
Heating Oil10,400 Wh/l 12,800 Wh/kg
Gasoline 9,700 Wh/l 12,200 Wh/kg
Butane 7,800 Wh/l 13,600 Wh/kg
LNG (-160C) 7,216 Wh/l 12,100 Wh/kg
Propane 6,600 Wh/l 13,900 Wh/kg
Ethanol 6,100 Wh/l 7,850 Wh/kg
Methanol 4,600 Wh/l 6,400 Wh/kg
NG 3,100 Wh/l 12,100 Wh/kg
Liquid Hydrogen 2,600 Wh/l 39,000 Wh/kg
150 Bar Hydrogen405 Wh/l 39,000 Wh/kg
NiMH Battery 280 Wh/l 100 Wh/kg
Li-Ion Battery200 Wh/l 150 Wh/kg
Lead-Acid Battery 40 Wh/l 25 Wh/kg
STP Propane 26 Wh/l 13,900 Wh/kg
STP NG11 Wh/l 12,100 Wh/kg
STP Hydrogen 3 Wh/l 39,000 Wh/kg

http://everything2.com/index.pl?node=energy%20density
http://xtronics.com/reference/energy_density.htm, http://hypertextbook.com/
http://www.ior.com.au/ecflist.html, http://www.batteryuniversity.com