FYI: Energy Units and Conversions
1 Joule (J) is the MKS unit of energy, equal to the force of one Newton acting through one meter.
1 Watt is the power of a Joule of energy per second
Power = Current x Voltage (P = I V)
1 Watt is the power from a current of 1 Ampere flowing through 1 Volt.
1 kilowatt is a thousand Watts.
1 kilowatt-hour is the energy of one kilowatt power flowing for one hour. (E = P t).
1 kilowatt-hour (kWh) = 3.6 x 106 J = 3.6 million Joules
1 calorie of heat is the amount needed to raise 1 gram of water 1 degree Centigrade.
1 calorie (cal) = 4.184 J
(The Calories in food ratings are actually kilocalories.)
A BTU (British Thermal Unit) is the amount of heat necessary to raise one pound of water by 1 degree Farenheit (F).
1 British Thermal Unit (BTU) = 1055 J (The Mechanical Equivalent of Heat Relation)
1 BTU = 252 cal = 1.055 kJ
1 Quad = 1015 BTU (World energy usage is about 300 Quads/year, US is about 100 Quads/year in 1996.)
1 therm = 100,000 BTU
1,000 kWh = 3.41 million BTU
Power Conversion
1 horsepower (hp) = 745.7 watts
Gas Volume to Energy Conversion
One thousand cubic feet of gas (Mcf) -> 1.027 million BTU = 1.083 billion J = 301 kWh
One therm = 100,000 BTU = 105.5 MJ = 29.3 kWh
1 Mcf -> 10.27 therms
Energy Content of Fuels
Coal 25 million BTU/ton
Crude Oil 5.6 million BTU/barrel
Oil 5.78 million BTU/barrel = 1700 kWh / barrel
Gasoline 5.6 million BTU/barrel (a barrel is 42 gallons) = 1.33 therms / gallon
Natural gas liquids 4.2 million BTU/barrel
Natural gas 1030 BTU/cubic foot
Wood 20 million BTU/cord
CO2 Pollution of Fossil Fuels
Pounds of CO2 per billion BTU of energy::
Coal 208,000 pounds
Oil 164,000 pounds
Natural Gas 117,000 pounds
Ratios of CO2 pollution:
Oil / Natural Gas = 1.40
Coal / Natural Gas = 1.78
Pounds of CO2 per 1,000 kWh, at 100% efficiency:
Coal 709 pounds
Oil 559 pounds
Natural Gas 399 pounds
