Renewable natural gas (RNG) is natural gas which is produced from renewable and sustainable sources such as food/agricultural waste, landfills, and sewage treatment plants. It is also known as sustainable natural gas or biomethane. After upgrade, RNG is fully interchangeable with pipeline quality conventional natural gas due to the chemical similarities with conventional natural gas (i.e., primarily comprised of methane). RNG, unlike conventional natural gas, does not depend on non-renewable sources such as underground fossil fuel reservoirs.
Production of RNG
Biogas is an umbrella term used to describe gas emitted from decaying biomass (organic matter) as a result of chemical reactions and anaerobic digestion by naturally occurring microorganisms. For example, landfills naturally produce a large amount of biogas, also known as landfill gas (LFG), from to the breakdown of food waste. Livestock operations such as feedlots produce biogas from animal waste, and water treatment plants produce biogas from human waste. However, while biogas contains a large proportion of valuable methane (45-65%), it also contains contaminants such as carbon dioxide (35-55%), water, and hydrogen sulfide which interfere and prevent the methane from being burned as a clean and efficient fuel source.
Biogas must be upgraded to RNG by removing those contaminants, much like conventional natural gas must also be upgraded. Once the RNG is sufficiently free of contaminants to be pipeline quality (95% or higher methane), it can be fed into existing natural gas pipelines for downstream distribution and use. RNG is fit for any purpose which conventional natural gas is used for, such as a heating fuel for homes, or as a transportation fuel in the form of compressed natural gas (CNG) or liquefied natural gas (LNG).
Unlike conventional natural gas, RNG is harvested as a natural by-product of waste created from human activity (e.g., landfills, wastewater, agricultural waste). Thus, RNG is continually produced and its sources will continually renew so long as humans continue to utilize landfills and wastewater treatment plants, or generate agricultural waste from food production. Collection of RNG as a fuel source reduces the amount of methane (a form of green house gas (GHG)) being emitted into the atmosphere.
Current RNG projects and government initiatives
In British Columbia, the CleanBC Plan aims to have 15% of natural gas supply consist of renewable gases such as RNG by 2030. Alberta and Québec have implemented carbon offset systems which award landfills and agricultural facilities for collecting and utilizing biogas. From 2021 to 2030, Canadian RNG production potential is expected to grow by 7% simply from industry and population growth.
As of 2021, there are approximately 279 biogas and RNG projects being operated in Canada ,and it is estimated that only 14% of Canada’s feasible biogas and RNG potential is being realized. This means new RNG projects can contribute significantly to helping Canada achieve its climate target of reducing methane emissions 30% below 2020 levels by 2030. It is estimated that by 2030, RNG production globally will be seven times that of 2020, and by 2050, global production will be 27 times that of 2020.
There are many notable examples of successful RNG projects in Canada, including:
- Since 2005, Capital Power has owned and operated the Clover Bar Landfill Gas facility which recovers LFG to produce RNG. This project produces enough energy to supply over 4,000 homes with renewable energy.
- From 2011, an RNG facility has been in production in Fraser Valley, combining anaerobic digestion and biogas upgrading technologies to produce RNG from agricultural waste. The company which operates that facility has subsequently acquired several other organic waste processing facilities in BC to produce RNG, with plans to expand in Alberta and Québec.
- In 2020, Enbridge partnered with other private sector parties to construct the largest RNG facility of its kind in Ontario, which captures otherwise environmentally harmful LFG. This project is projected to supply over 8,500 homes with renewable energy.
- Also in 2020 in Québec, the Canadian subsidiary of a European company which is a leader in LFG recovery also began construction of an LFG recovery facility that will produce RNG. This project will produce energy for about 8,000 homes.
RNG is a renewable source of energy which is inevitably emitted from human activity. Utilization of RNG will reduce harmful GHGs from being emitted into the atmosphere. Thus, it is a doubly beneficial method which reduces environmental harm and brings humanity closer to a sustainable energy consumption future. Given current emissions targets, RNG utilization is likely to become more prevalent as an energy source in Canada.
Special thanks to Summer Law Student, Jack Yuan, who assisted in preparing this insight.
- BC Renewable and Low-Carbon Gas Supply Potential Study, ENVINT, CBER & Associates↩
- Coalition for RNG infographic ↩