Amazing factoid from Harper's Index...

[WannaJumpMyScooter]

Average number of calories of oil that are used to make each calorie of food Americans eat: 7

[Gabi Hayes]

1. time to go on a "diet." ...... deals directly with energy cost of food

[Demit]

2. Eww. Where do the other six calories go, does it say?

[lectrobyte]

4. The calories from oil are used for fuel and fertilizer. There's energy

involved at every step in producing, from the tractor plowing up the gound to plant something, to the semi hauling it to the grocery store.

[Javaman]

11. is the amount of calories included in that, that is requires to

extract the oil from the ground?

[WannaJumpMyScooter]

5. Not cooking oil, gasoline, plastic, and fertilizer

uses of oil.

[Demit]

6. Oh. LOL! Never heard gasoline units translated into calories before.

I guess that's what threw me.

[WannaJumpMyScooter]

7. Yeah, I had to read it twice. BTW, gasoline is

19,000calories per liquid pound, from what I can find.

[karlrschneider]

13. You mixed up calories with BTUs

gas yields around 20,000 BTU/lb which is around 5 million calories!
:D

[WannaJumpMyScooter]

14. thanks. that makes more sense then

hmmmm

[lectrobyte]

3. I'd heard statistics like this before. It's one of the reasons that

peak oil is going to be very interesting for us.

[WannaJumpMyScooter]

8. Here's some more

from http://www.ocean.washington.edu/courses/envir202/energy-numbers.pdf

Energy Equivalencies
1 barrel of oil = driving 1400 km (840 miles) in average car
1 kwh electricity
= 1½ hours of operation of standard air conditioner
= 92 days for electric clock
= 24 hours for color TV

One million Btu equals approximately
90 pounds of coal
125 pounds of ovendried wood
8 gallons of motor gasoline
10 therms of natural gas
1.1 day energy consumption per capita in the U.S.

Biomass energy
Cord: a stack of wood comprising 128 cubic feet (3.62 m3); standard dimensions
are 4 x 4 x 8 feet, including air space and bark. One cord contains approx. 1.2
U.S. tons (oven-dry) = 2400 pounds = 1089 kg
o 1.0 metric tonne wood = 1.4 cubic meters (solid wood, not stacked)
o Energy content of wood fuel (HHV, bone dry) = 18-22 GJ/t (7,600-9,600
Btu/lb)
o Energy content of wood fuel (air dry, 20% moisture) = about 15 GJ/t
(6,400 Btu/lb)
Energy content of agricultural residues (range due to moisture content) = 10-17
•
GJ/t (4,300-7,300 Btu/lb)
Metric tonne charcoal = 30 GJ (= 12,800 Btu/lb) (but usually derived from 6-12 t
•
air-dry wood, i.e. 90-180 GJ original energy content)
Metric tonne ethanol = 7.94 petroleum barrels = 1262 liters
•
o ethanol energy content (LHV) = 11,500 Btu/lb = 75,700 Btu/gallon = 26.7
GJ/t = 21.1 MJ/liter. HHV for ethanol = 84,000 Btu/gallon = 89 MJ/gallon
= 23.4 MJ/liter

ethanol density (average) = 0.79 g/ml (= metric tonnes/m )
Metric tonne biodiesel = 37.8 GJ (33.3 - 35.7 MJ/liter)

biodiesel density (average) = 0.88 g/ml (= metric tonnes/m )

Fossil Fuels

Barrel of oil equivalent (boe) = approx. 6.1 GJ (5.8 million Btu), equivalent to
•
1,700 kWh. "Petroleum barrel" is a liquid measure equal to 42 U.S. gallons (35
Imperial gallons or 159 liters); about 7.2 barrels oil are equivalent to one tonne of
oil (metric) = 42-45 GJ.
Gasoline: US gallon = 115,000 Btu = 121 MJ = 32 MJ/liter (LHV). HHV =
•
125,000 Btu/gallon = 132 MJ/gallon = 35 MJ/liter
o Metric tonne gasoline = 8.53 barrels = 1356 liter = 43.5 GJ/t (LHV); 47.3
GJ/t (HHV)
3
o gasoline density (average) = 0.73 g/ml (= metric tonnes/m )
Petro-diesel = 130,500 Btu/gallon (36.4 MJ/liter or 42.8 GJ/t)
•
3
o petro-diesel density (average) = 0.84 g/ml (= metric tonnes/m )
Note that the energy content (heating value) of petroleum products per unit mass
•
is fairly constant, but their density differs significantly – hence the energy content
of a liter, gallon, etc. varies between gasoline, diesel, kerosene.
Metric tonne coal = 27-30 GJ (bituminous/anthracite); 15-19 GJ (lignite/sub-
•
bituminous) (the above ranges are equivalent to 11,500-13,000 Btu/lb and 6,500-
8,200 Btu/lb).
o Note that the energy content (heating value) per unit mass varies greatly
between different "ranks" of coal. "Typical" coal (rank not specified)
usually means bituminous coal, the most common fuel for power plants
(27 GJ/t).
Natural gas: HHV = 1027 Btu/ft3 = 38.3 MJ/m3; LHV = 930 Btu/ft3 = 34.6
•
MJ/m3
o Therm (used for natural gas, methane) = 100,000 Btu (= 105.5 MJ)

and

Carbon content of fossil fuels and bioenergy feedstocks
coal (average) = 25.4 metric tonnes carbon per terajoule (TJ)
•
o 1.0 metric tonne coal = 746 kg carbon
oil (average) = 19.9 metric tonnes carbon / TJ
•
1.0 US gallon gasoline (0.833 Imperial gallon, 3.79 liter) = 2.42 kg carbon
•
1.0 US gallon diesel/fuel oil (0.833 Imperial gallon, 3.79 liter) = 2.77 kg carbon
•
natural gas (methane) = 14.4 metric tonnes carbon / TJ
•
1.0 cubic meter natural gas (methane) = 0.49 kg carbon
•
carbon content of bioenergy feedstocks: approx. 50% for woody crops or wood
•
waste; approx. 45% for graminaceous (grass) crops or agricultural residues

[lectrobyte]

9. That's a great reference, thanks. I'd only seen articles like this

before, but that data helps to put it in more perspective.

http://www.fromthewilderness.com/free/ww3/100303_eating_oil.html

that point out just how much we are actually "eating petroleum." A short excerpt:

In the United States, 400 gallons of oil equivalents are expended annually to feed each American (as of data provided in 1994).7 Agricultural energy consumption is broken down as follows:

· 31% for the manufacture of inorganic fertilizer

· 19% for the operation of field machinery

· 16% for transportation

· 13% for irrigation

· 08% for raising livestock (not including livestock feed)

· 05% for crop drying

· 05% for pesticide production

· 08% miscellaneous8

Energy costs for packaging, refrigeration, transportation to retail outlets, and household cooking are not considered in these figures.

[WannaJumpMyScooter]

10. and I still don't think that is right

you have transportation of the animals not included, that I can see

and there is transportation of the oil itself, that can't be cheap, or ignored.

[Phillycat]

12. Read "The Omnivore's Dilemma" for more info

Fascinating and surprisingly entertaining book. By Michael Pollan.