What is Renewable Natural Gas, and how is it made?
When organic waste (like rotting food or cow manure) decomposes, it releases biogas into the atmosphere. That raw biogas can be captured and purified to create Renewable Natural Gas.1
Renewable Natural Gas is interchangeable with conventional natural gas. It’s injected into our natural gas distribution system, reducing the amount of conventional natural gas needed.2
How Renewable Natural Gas is made
Farms, landfills and other suppliers like the City of Surrey have teamed up with us to capture biogas from sites across the Lower Mainland. Sometimes our suppliers will purify the biogas to make RNG themselves, and other times we’ll take care of the purification process.
Where we get biogas from:
- wastewater treatment plants
- agricultural waste
- landfill waste
- residential or commercial organic waste (e.g. from municipal curbside pickup)
In each case, the basic process of biogas production is the same:
- Anaerobic digestion:
- Organic waste is delivered to an oxygen-free, temperature-controlled environment, like a digester tank.
- Naturally occurring bacteria break down the organic waste, creating raw biogas as a byproduct of this digestion process. Biogas is primarily composed of methane, but it also contains between 25 and 50 per cent carbon dioxide and small quantities of other gases.
- First, we remove contaminant gases through a careful gas cleaning process that leaves only methane and carbon dioxide.
- Then the carbon dioxide, which lowers the heating value of the gas, can be removed. For our Salmon Arm Landfill Renewable Natural Gas operation, we use a made-in-BC technology called pressure swing adsorption (PSA) to perform this final cleaning step.
- Once the gas has been cleaned, it only contains methane and a small amount of nitrogen, making it almost impossible to distinguish from conventional natural gas. This purified biogas is called biomethane, or Renewable Natural Gas.
Renewable Natural Gas is injected into FortisBC’s existing pipeline system and delivered to our customers, just like conventional natural gas. If you sign up for Renewable Natural Gas, you don’t need to change your appliances or do anything differently.
1Renewable Natural Gas is produced in a different manner than conventional natural gas. It is derived from biogas, which is produced from decomposing organic waste from landfills, agricultural waste and wastewater from treatment facilities.
The biogas is captured and cleaned to create carbon neutral Renewable Natural Gas (also called biomethane).