Energy Density
MaterialBy Volume   By Mass
Diesel Fuel10,700 Wh/L12,700 Wh/kg45.7 kJ/g10.9 Cal/g
Heating Oil10,400 Wh/L12,800 Wh/kg46.1 kJ/g11.0 Cal/g
Gasoline 9,700 Wh/L 12,200 Wh/kg43.9 kJ/g10.5 Cal/g
Butane 7,800 Wh/L 13,600 Wh/kg48.6 kJ/g11.6 Cal/g
LNG (-160C) 7,216 Wh/L12,100 Wh/kg43.6 kJ/g10.4 Cal/g
Propane 6,600 Wh/L13,900 Wh/kg50.0 kJ/g12.0 Cal/g
Ethanol 6,100 Wh/L7,850 Wh/kg26.3 kJ/g6.8 Cal/g
Methanol 4,600 Wh/L 6,400 Wh/kg23.0 kJ/g5.5 Cal/g
NG 3,100 Wh/L12,100 Wh/kg43.6 kJ/g10.4 Cal/g
Liquid Hydrogen 2,600 Wh/L 39,000 Wh/kg140.4 kJ/g33.6 Cal/g
150 Bar Hydrogen405 Wh/L39,000 Wh/kg140.4 kJ/g33.6 Cal/g
NiMH Battery 280 Wh/L100 Wh/kg0.4 kJ/g0.1 Cal/g
Li-Ion Battery200 Wh/L150 Wh/kg0.5 kJ/g0.1 Cal/g
Lead-Acid Battery 40 Wh/L 25 Wh/kg0.1 kJ/g0.0 Cal/g
STP Propane 26 Wh/L13,900 Wh/kg50.0 kJ/g12.0 Cal/g
STP NG11 Wh/L12,100 Wh/kg43.6 kJ/g10.4 Cal/g
STP Hydrogen 3 Wh/L39,000 Wh/kg140.4 kJ/g33.6 Cal/g
Fat 11,000 Wh/kg39    kJ/g9    Cal/g
Protein 4,800 Wh/kg17    kJ/g4    Cal/g
Carbohydrate 4,800 Wh/kg17    kJ/g4    Cal/g

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