RE: Evaluating energy use, Aug. 25.
Estimating one’s carbon footprint: the main sources of emissions for a family, are the vehicle, heating and cooling the home, and powering the lights and appliances. It’s best to take the whole year into account because emissions vary with the seasons. Any starting date is fine as long as the end date is a year later.
The vehicle: fuel bills can be collected for a year or one can multiply kilometres (km) travelled in a year by the average litres (L) burned per km. Each L of gasoline produces 2.31 kilogram (kg) of CO2e.
The home: if natural gas is used for heating, look up a year’s worth of bills to find out what volume of gas was burned. A cubic metre (m3) of natural gas releases 2.4kg of CO2e. If a different fuel is used the CO2e released can be found on the internet.
The kilowatt hour (kWh) of energy used to run the home can be found from a year’s worth of electricity bills. Ontario’s electricity generation is very clean. 1 kWh of electricity releases 0.044 kg CO2e.
My experience: In 2018, I drove a Honda Fit that averaged 6.8 L/100km. Now I drive a Prius plug-in hybrid that averages 1.45 L/100 km. I drive about 12,000km per year, so the Honda would have released 1,885kg, but only 402kg from the Prius.
In 2018, I burned 1,980m3 of natural gas to heat water and my home, and 2,750kWh of electricity to power everything. The gas released 4,752kg and the electricity 121kg.
Between 2019 and 2021, I purchased the Prius, added solar panels to the roof of my garage, installed battery storage, switched water heating from gas to electricity and home heating from a gas furnace to an air exchange heat pump, which uses electricity but supplements with gas on very cold days.
This year, I expect charging my car and powering the house will use about 10,000kWh of electricity, but only 4,100kWh (180 kg CO2e) will come from the grid, the rest is free from the sun. The heat pump will use about 530m3 of gas and release 1,272 kg.
My carbon footprint from car + natural gas + electricity in 2018 was 6,758kg or about 6.8 tonne, and for 2022, 1,842kg or about 1.9 tonne.
Ron Moore,
Hillsburgh