The City will begin producing renewable natural gas (RNG) from Green Bin organic waste in the coming weeks.  As per the strategy approved by City Council, the RNG will be blended with the natural gas that the City buys to create a low-carbon fuel blend that will be used to power City vehicles and heat City-owned facilities, allowing for greenhouse gas emission reductions across the organization.

 

The City, working with Enbridge Gas Inc., has installed infrastructure at the Dufferin Solid Waste Management Facility that will allow it to create renewable natural gas (RNG) from Green Bin organics. The new equipment will enable the City to take the raw biogas produced from processing Green Bin organics, turn it into RNG and inject it into the natural gas grid for City use.

As per the strategy that was approved by City Council last year, the RNG produced will be blended with the natural gas that the City buys to create a low-carbon fuel blend that will be used across the organization to power vehicles and heat City-owned facilities, allowing for a reduction in greenhouse gas emissions Citywide. The City will not start using the gas until the beginning of 2022 to ensure production capacity has stabilized. Until then, the gas will be stored in the grid.

The City has also identified potential biogas/landfill gas upgrading opportunities at several other City waste facilities including the Disco Road Solid Waste Management Facility, Green Lane Landfill, and Keele Valley Landfill. All four sites combined would have the potential to produce enough gas to fulfill the City’s entire natural gas needs annually (excluding City Agency, Boards and Commissions).

The next facility to receive RNG infrastructure will be the Disco Road Solid Waste Management Facility, with plans to have this site up and running by the end of 2023.

Circular model showing how waste can ultimately be used to fuel the trucks that collect it. In step one organic waste is produced; in step two organic waste is collected; in step three organic waste is processed through anaerobic digestion; in step four the biogas produced from processing organics is upgraded to renewable natural gas; in step five the renewable natural gas is injected into the natural gas grid; in step six the end use for the renewable natural gas is developed (eg. heat, electricity or fuel)
Circular model showing how waste can ultimately be used to create green energy.

The City’s existing and closed landfill sites and anaerobic digestion (organics processing) facilities are some of the largest producers of biogas and landfill gas in Ontario. As a result, the City’s Solid Waste Management Services Division has been exploring opportunities to harness the green energy potential of these gases.

In 2015, the Division identified RNG as a top priority for biogas management and started to search for technologies and partnerships to upgrade its biogas and landfill gas to RNG. When looking at the different technologies and options for upgrading and transporting the gas, the Division took a triple-bottom-line approach that considered the economic, social and environmental benefits.

The City has been working with Enbridge Gas Inc. to create and realize the vision for the project at the Dufferin Solid Waste Management Facility. This includes the design and construction of the facility, as well as its operation and maintenance for the first 15 years.

The City currently consumes 50 million cubic metres of natural gas (NG) annually, and the City’s Agencies, Boards and Commissions (ABCs) consume an additional 60 million cubic metres of NG annually, for a combined total consumption of 110 million cubic metres annually. Incorporating RNG into the mix will allow the City to create a low-carbon fuel blend that will be used to fuel City vehicles and heat City facilities. If landfill gas/biogas upgrading is realized at all four sites that the City has identified, the result would be enough renewable gas to fulfill the City’s entire natural gas needs annually.

Biogas upgrading helps achieve the goals of the City’s TransformTO Climate Action Strategy, specifically the goal of becoming net zero by 2050 or sooner and the goal of generating 1.5 million gigajoules of energy from biogas by 2030. It also supports the Net Zero Carbon Plan for City Buildings and the City’s Long Term Waste Management Strategy and move toward a circular economy.

City biogas/landfill gas utilization potential

Site Estimated year of

completion

Estimated cubic metres of RNG/year **RNG % of fuel blend/year Carbon Reduction (tonnes of CO2e/year) Gigajoules (GJ) of energy
from biogas/year
% of TransformTO goal of 1.5 million GJ of energy from biogas (each year)
Dufferin 2021 3,380,000 6.8 9,357 128,450 8.6
Disco Road 2023 4,609,440 9.2 12,759 175,159 11.7
*Green Lane Landfill 2026 25,757,082 51.5 55,365 978,769 65.3
*Keele Valley Landfill TBD 20,023,958 40.1 37,650 760,910 50.7
All Sites 2025 53,770,480 107.5 115,131 2,043,288 136.2

 

*The City is currently reviewing all available green energy technologies for landfill gas utilization.

**Based on City consumption only (excludes ABCs)

Both biogas and landfill gas can be upgraded to create RNG. The biogas produced through anaerobic digestion is made up primarily of methane, but also includes carbon dioxide, oxygen, nitrogen, water, sulphur, and various non-methane organic compounds.

Biogas upgrading involves purifying the gas to remove carbon dioxide and other contaminants. The result is a gas that is more than 90 per cent methane and can be injected directly into natural gas pipelines. The RNG can then be transported to the City’s natural gas fueling stations and used to fuel its trucks.

Biogas at the City’s anaerobic digestion facilities is currently flared (burned), which is common industry practice for managing biogas, but does not take advantage of its renewable energy potential.

While chemically identical to traditional fossilized natural gas, RNG is a renewable resource that can be produced using materials that are readily accessible through the City’s Green Bin organics program and does not require mining or drilling activities.

RNG is also more environmentally friendly than fossil fuels such as diesel. Once injected into the natural gas pipeline, it can be used to fuel vehicles or provide electricity or heat.

The production of RNG from biogas has the environmental benefit of closing the carbon loop by capturing the biogas produced instead of flaring/burning it off, upgrading the biogas to RNG pipeline quality, and then using it to displace a fossil fuel with a renewable green fuel.

RNG generated from food waste is considered carbon neutral, if not carbon negative, because the reduction in emissions by not extracting and burning petroleum-based fuel, and the emissions avoided by not sending organics to landfill, exceed the direct emissions associated with the production and use of RNG. While compressed natural gas is 20 per cent better than diesel, RNG is 100 per cent to 120 per cent better.