Energy Insights

Energy Insights

What’s this term: dekatherm? How much heat in cubic feet?

You probably have a good understanding of the volume of a gallon of milk or a pound of sugar. You can see it and feel it.

But measuring natural gas is a bit harder to visualize. Natural gas is measured in cubic feet and is a unit of volume equal to a cube one foot long on each side.

Here are other measurements we refer to commonly.

  • Ccf: the volume of 100 cubic feet (cf)
  • Mcf: one thousand cf
  • MM: one million cf
  • Bcf: one billion cf

Then there’s Btu, or British thermal units. One Btu is the amount of energy needed to heat one pound of water 1 degree at sea level. One million Btu is abbreviated as MMBtu and also known as a dekatherm.

Why is this important?

In the United States, natural gas can be priced in units of dollars per therm, dollars per MMBtu or dollars per cubic feet. The heat content of natural gas per physical unit (such as Btu per cubic foot) is needed to convert these prices from one price basis to another.

If you look at our Transco system, which reaches 13 states, the daily system capacity is 17.9 million dekatherms, which is enough to provide natural gas to more than 38 million U.S. households on an average January day.

Now you know!