Energy By the Numbers


  1. Food
  2. Fuel
  3. Needs

Food

From USDA Home and Garden Bulletin Number 72.

Food

Mass

(g)

Energy

(MegaJoules)

Density

(kJ/g)

Cheddar Cheese

28

0.477

17

Milk 2%

244

0.507

2.07

Halibut

85

0.498

5.86

Rice, wild

164

0.694

4.24

Apple

138

0.339

2.46

Fuel

From ORNL, these sources of energy are physical heat rather than edible food. These liquid fuels assume standard temperature and pressure.

Fuel

Energy

Density

Units

Ethanol HHV

23.4

MJ/litre

Propane

25.5

MJ/litre

Automotive Gasoline

34.8

MJ/litre

Jet Fuel (naptha)

35.5

MJ/litre

Crude Petroleum

38.5

MJ/litre

Diesel Motor Fuel

38.7

MJ/litre


We can also use natural solid material to provide (heat) energy. The following values also come from ORNL.

Fuel

Energy

Density

Units

Switchgrass

17.1

MJ/kilogram

Wood - HHV, bone dry

22

MJ/kilogram

Coal - Anthracite

25.2

MJ/kilogram

HHV - higher heating value

Needs

Human's Annual Energy Needs, with drastic assumptions about activity levels.

Human

Time of Life

Joules

x109

Infant

1.1456

Child

2.75

Male

3.36

Female

3.05


by Mark Foster Mortimer