Page 47 - Geothermal Energy Renewable Energy and The Environment

30 Geothermal Energy: Renewable Energy and the Environment

hour, its power consumption would be expressed as 50 Wh. Similarly, a geothermal power generator that produced
5 million joules per second (a modest generator) for a 24-hour period would provide 120 MWh of power.
Other units are often used when discussing energy and power. Some useful equivalencies are given below:
• 1 joule (J) = 0.2388 calories (cal) = 9.478 British thermal units (Btu)
6
5
• 1 kWh = 3.6 × 10 J = 8.6× 10 cal = 3412 Btu
The following table provides equivalencies for a variety of units used throughout this book.

sI Unit other Units
1 joule (J) = 1 Newton – m
= 0.2388 calories
= 9.478 BTU
1 meter = 3.281 feet
1 megaPascal (MPa) = 9.869 atm
= 10 bars
1 kg = 2.205 lbs
1 kg of force = 9.8066 newton (N)
1 Kelvin (K) = 273°C
1 Pa–m 3 = 1J