Winter. Cold temperatures. Indoor heating. Good thing we have plenty of power sources to keep our homes, and ourselves, nice and snug in the cold months. Canada’s long winters require several months of heating and Ontario’s power needs this winter will demand between 22–23 gigawatts of electricity.
Ontario’s electricity is generated, in descending order, from nuclear, hydro-power, natural gas, wind, and solar.
An additional renewable energy source is biofuels. While these currently contribute only around 1 per cent of the supply, there are still untapped opportunities to convert waste products into energy.
Biofuels are produced from living organisms or metabolic by-products, like organic matter or food waste. The process of anaerobic digestion produces heat, and/or gaseous liquids or gas that can be used as an additive or to generate electricity.
The two most common biofuels are ethanol and biodiesel. Ethanol is typically made by fermenting biomass high in carbohydrates, starches, or sugars, such as sugar cane, palm oil, or corn stalks. Leftovers from crop harvests are beneficial, while growing crops specifically for biofuels is not always more energy efficient over other methods.
One way to create a more favourable balance of input versus output is to use waste that is a by-product of another process, and which is generated regardless of whether the waste product is ‘recycled’ or not.
Biodiesel, for example, is made by combining alcohol with additives such as animal fat, old vegetable oil, or recycled cooking grease.
Biogas is created in the same way as biofuels. Methane is the most common biogas and seeps out of landfill sites, sewage pits on large animal farms, or municipal wastewater treatment facilities. It is a far more harmful gas to our atmosphere than carbon dioxide.
Toronto’s own ZooShare (zooshare.ca) is planning North America’s first biogas plant to use ‘zoo poo.’ Once the processing plant has been built, it will use manure from the Toronto Zoo as well as food waste from a grocery chain for renewable power. Construction of the plant beside the zoo is scheduled for July, with operation planned to start next winter.
Within 50 to 60 days, the process of anaerobic digestion creates gas that can be used to generate electricity. Using this organic matter prevents it from going to landfill, helps reduce overall waste, and prevents odours and runoff. ZooShare’s biogas plant will reduce greenhouse gas emissions equivalent to the amount generated by about 2,100 cars, and will produce high-quality fertilizer that returns valuable nutrients to the soil.
Input materials for the plant are predicted to be 14,000 tonnes of inedible food waste per year, part of the $31 billion worth of food wasted annually. (Look for my next column in March, which will focus on food waste.)
Zoo manure will contribute around 3,000 tonnes. The plant will feed directly into the Ontario power grid, producing enough energy for 250 homes. Hopefully, the departure of the zoo’s elephants will not negatively affect the amount of ‘output.’
Other Biogas Options
In 2012, ZooShare founder Daniel Bida and Beacher Ronn Stevenson investigated the possibility of a dog-waste digester. They did their research, wrote a business case, and applied for a Live Green Toronto grant. Their plan was for a pilot project near Kew Beach dog park.
Local dog owners would have been able to purchase special bags from local pet stores and receive a registered chit, which would act like a key for doggie-doo disposal in the digester, to prevent it being used as a regular garbage can. In return, users would have received a discount on pet food purchases. Energy from the digester was going to be used to power some of the lighting along the boardwalk.
The proposal received support from the Beach Dog Association and our local councillor but did not receive a grant. Stevenson said the city’s waste department had concerns about safety due to the methane gas it produces. It would have been modelled on similar digesters already being used safely in other cities, like PooPower! in Melbourne, Australia.
“I think our idea was just a little before its time for Toronto,” says Stevenson.
That doesn’t mean the animal poo duo are sticking their heads in the sand; they are considering options for a small portable digester for demonstrations. Regulations and approval for something small may be easier to come by.
Waste not, want not. As ZooShare’s website says: “There is no such thing as waste – only wasted resources.”
Martina Rowley is an environmental communicator
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