### World power consumption

World power consumption is 15 TW. World electricity consumption is
2 TW.

### Useful conversion factors

To change TWh per year to GW, divide by 9.

1 kWh/d per person is the same as 2.5 GW per UK, or 22 TWh/y per UK

To change mpg (miles per UK gallon) to km per litre, divide by 3.

At room temperature, 1 kT = 140eV

At room temperature, 1 kT per molecule = 2.5 kJ/mol.

• If the meter reads 100s of cubic feet, take the number of units used,
and multiply by 32.32 to get the number of kWh.
• If the meter reads cubic metres, take the number of units used, and
multiply by 11.42 to get the number of kWh.

## Calorific values of fuels

Crude oil: 37 MJ/l; 10.3 kWh/l.
Natural gas: 38 MJ/m3. (Methane has a density of 1.819 kg/m3.)
1 ton of coal: 29.3 GJ; 8000 kWh.
Fusion energy of ordinary water: 1800 kWh per litre.

## Heat capacities

The heat capacity of air is 1 kJ/kg/°C, or 29 J/mol/°C. The density of air
is 1.2 kg/m3. So the heat capacity of air per unit volume is 1.2 kJ/m3/°C.

Latent heat of vaporization of water: 2257.92 kJ/kg. Water vapour’s
heat capacity: 1.87 kJ/kg/°C. Water’s heat capacity is 4.2 kJ/l/°C.

Steam’s density is 0.590 kg/m3.

## Pressure

Atmospheric pressure: 1 bar 105 Pa (pascal). Pressure under 1000 m of
water: 100 bar. Pressure under 3000 m of water: 300 bar.

kWh/t-km
inland water 0.083
rail 0.083
truck 0.75
air 2.8
oil pipeline 0.056
gas pipeline 0.47
int’l water container 0.056
int’l water bulk 0.056
int’l water tanker 0.028
Table I.8. Energy intensity of transport modes in the USA. Source: Weber and Matthews (2008). 