The closed-loop system is set to be operational from March 2020, when the city’s food scraps and biodegradable waste will start being taken to a newly constructed anaerobic digestion facility for processing. The biogas released will be captured and converted to renewable natural gas (RNG) – and then injected into the city’s natural gas grid.

The system will significantly reduce the carbon footprint of Toronto’s waste fleet, with estimates suggesting the facility will be able to produce enough gas each year to power the majority of its collection vehicles.

Since 2010, Toronto has been gradually transitioning away from diesel-powered trucks to quieter, more environmentally friendly ones. The city has also constructed a number of RNG refuelling stations.

Once in the grid, the gas could also be used for electricity or heating.

A circular approach

Both biogas and gas created by waste in landfill can be upgraded to create RNG by removing carbon dioxide and other contaminants. The biogas produced from Toronto’s food waste is currently flared – or burnt off – which the city notes is standard industry practice, but does not take advantage of its potential as a renewable power source.

What is Loop and how does it work?

As part of its ambition to become a circular economy, Toronto hopes to create four RNG processing sites, producing gas from two of its anaerobic digestion facilities for organic waste and two of its landfill sites. Once they are up and running, the city says they will be able to produce the gas equivalent of taking 35,000 cars off the road for a year.

RNG is considered a carbon negative product, because the overall reduction in emissions from not using fossil fuels and sending organic waste to landfill outweighs the emissions from using and creating RNG.

The problem of food waste

Globally, food makes up a huge part of our waste. Around a third of all the food produced globally is never eaten.

 

If food waste were a country it would be the third biggest emitter of greenhouse gases in the world, according to the Food and Agriculture Organization of the United Nations. When you take into account the carbon footprint created by growing, harvesting, transporting, processing and storing food, the waste is almost equivalent to global road transport emissions.