Natural gas is measured in Gigajoules (GJ), a metric energy measure. One GJ of natural gas is roughly equal to 26 litres of fuel oil, 40 litres of propane, or 278 kilowatt hours of electricity.
Your total monthly cost of natural gas will change depending on the amount of GJ’s you use every month.
The three charges that make up the total cost of natural gas on your bill are:

This charge is a monthly charge to cover some of the fixed costs of providing natural gas service, like meter readings, pipeline maintenance, customer support, and 24-hour emergency services. (It is regulated by the New Brunswick Energy and Utilities Board (EUB) and is only applicable to residential, SGSC and GS rate classes.)
This charge is the price you pay to use the company’s infrastructure which is the pipeline system that distributes natural gas to you. The EUB regulates the rates for natural gas distribution service that we charge to our customers. Those rates may only be changed with the approval of the Board. Distribution rates are based on market conditions and may change significantly over time.
This charge is the cost of the natural gas that you consume. You can have Enbridge Gas New Brunswick, the regulated utility, supply your natural gas or you can sign a contract for gas supply with an independent Gas Marketer licensed by the New Brunswick Energy and Utilities Board.