Useful Energy NumbersUseful Energy Numbers
Here are some numbers to help you in energy analysis.
Some equivalences:
1 BTU  252.16 calories  .25 Calories (kcal)  1.055 kilojoules 
1 gallon gas  125,000 BTU  132 Megajoules 
1 kilowatthour  3413 BTU (equivalence)  10399 BTU at generator (DoE) 
One solar peak watt  2 kWh/year in California  21.2 cents/year @ U.S. average 
MPG  125,000/(BTUs per mile)  235/(litres per 100km) 
1 gallon gas  1.44 gal ethanol  .89 gal diesel  1.05 gal biodiesel 
The
Google Calculator can do many units conversions for you.
Some useful facts:
 A typical car is estimated about 120M BTUs for manufacture, equivalent to 1,000 gallons of gas. This goes up with weight, also up with special metals like nickel.
 U.S. Agriculture burns 400 gallons of gas equivalent for each American.
 One Calorie of average food thus consumes 10 Calories of fossil fuel energy.
 Refining and transport takes 22% of energy (ie. 82% of energy from the well reaches your tank.)
 10,400 BTUs of heat in a generator produces 1 kwhour of electricity at the home.
