Natural gas is a mix of Methane (~95%), Ethan (~3%) and other gases, and here are some common unites for LNG.
- C—equals one hundred (100)
- Ccf—equals the volume of 100 cubic feet (cf) of natural gas This is also known as Therm
- M—equals one thousand (1,000)
- MM—equals one million (1,000,000)
- Mcf—equals the volume of 1,000 cubic feet (cf) of natural gas
- MMBtu—equals 1,000,000 British thermal units (Btu) (One Btu is the heat required to raise the temperature of one pound of water by one degree Fahrenheit.)
- Therm—One therm equals 100,000 Btu, or 0.10 MMBtu
In the above list there is the unit BTU. So, what is this unit?
The British Thermal Unit, or BTU, is an energy unit. It is approximately the energy needed to heat one pound of water for 1 Fahrenheit. 1 BTU = 1,055 joules. 1BTU/hour = 0.293 watt.
On the other hand, what is the Gross Heating value of the natural gas?
On average, one cubic feet of natural gas at atmospheric pressure and 60 °F contain 900-1100 Btu, and this is called Standard Cubic Feet (SCF). To make this more appealing let’s compare it to wood. As we know, Air-dried hardwood firewood typically contains about 20 percent moisture, or 0.83 pound of dry wood and 0.17 pound of water. The available heat value is then 7,100 Btu per pound (0.83 pound x 8,600 Btu/pound).
That means one pound of wood approximately equal to seven standard cubic feet of natural gas, and approximately one cubic feet of Liquefied Natural Gas contains about 600 SCF.