How is your carbon footprint calculated ?
Your carbon footprint refers to the amount of
greenhouse gases that you generate in the form of carbon dioxide.
The amount of carbon dioxide generated is is typically expressed in
metric tonnes (tCO2).
The vast majority of carbon dioxide emissions generated by
individuals are generated through transportation or heating (and
cooling) of homes. More specifically, the burning of gas, oil or
other fossil fuels results in the release of carbon dioxide. In the
case of cars or airplanes, this occurs directly in the combustion
chamber of the engines and the associated emissions are known as
direct emissions since they occur at the point of
consumption. When we consume electricity, the emissions are
indirect since they occurs at the generation plant and not
at the point of consumption.
The amount of carbon dioxide generated by direct emissions can be
calculated through the use of emission factors. An
emission factors is the ratio of carbon dioxide generated for a
given quantity of fuel. It varies from fuel to fuel but is dependant
only on the fuel type . Indirect emissions from electrical power
consumption are estimated through the use of electrical
emission coefficients. This number varies by region and
location. For example, areas that depend on coal for power
generation have higher coefficients than areas using oil.
Hydroelectric power has the lowest coefficient since it does not
rely on combustion for power generation.
Here are some more details on each of the components of the
carbon footprint calculations:
Calculating carbon emissions from your home
- Emission factors for the various fuel types are based on
factors published by the US Energy Information Administration (EIA).
- Electrical emission coefficients for Canada and Europe are
based on data published by the International Energy Agency (IEA).
US electrical emission coefficients are based on data published
by the US Energy Information Administration (EIA).
- There are very large variations in electrical emission
coefficients from region to region due to the various sources
of power generation.
- In Canada, Quebec which draws almost all of its
electrical energy from Hydroelectric power, has the lowest
coefficients. Ontario also has a relatively low electrical
emission coefficient due to some reliance on nuclear energy.
Alberta, with a very heavy reliance on fossil fuels, has the
- In the US, the median coefficient is higher than in Canada
due to a heavier reliance on fossil fuels and particularly due
to the use of coal. Amongst the states with the lowest
coefficients are Vermont, Oregon and Idaho with the highest
coefficients occurring in North Dakota, Indiana and Wyoming.
- In Europe, countries that rely on hydroelectric and nuclear
power such as Norway and France have low electrical emission
coefficients. Germany, Italy, Spain and Greece are amongst the
Calculating carbon emissions from your cars
- Car emissions are directly related to the quantity of fuel
burned which is in turn related to the fuel efficiency of your
- Fuel efficiencies vary from model to model but also depend
on driving conditions (eg. highway versus city driving). Be sure
to use a fuel efficiency factor that reasonably reflects your driving patterns.
- Your carbon footprint is calculated using an assumption of
19.6 lbs/gal of gasoline and 22.4 lbs/gal of diesel
- Although the combustion of 1 lb of diesel results in
the release of more emissions that 1 lb of gasoline, a pound of
diesel typically translates into a larger travel distance .
Overall emissions effectiveness thus depends on fuel efficiency.
Calculating carbon emissions from air travel
- Air travel definitions and factors are from the
GHG Protocol Mobile Combustion Tool. The emissions factors
for short and long haul flights are originally from the UK
Department for Environment, Food and Rural Affairs (DEFRA).
- Aircrafts consume more fuel during takeoffs and landings and
thus short haul flights have a higher per unit distance
consumptions that longer flights.
- A higher portion of the overall consumption is assigned to
business class flyers since these seats occupy mores space (a
factor of 1.3 is used versus economy class).
- Charter flights are typically operated at higher occupancy
rates and this results in lower per person contributions than
regular flights (a factor of 0.8 is used versus regular economy
Calculating the carbon footprint of business or corporations is
significantly more complex and involves a thorough evaluation of all
operations. Please contact
ZeroGHG for help with calculating your corporate footprint.
ZeroGHG can also provide you with assistance in calculating the carbon footprint of your for
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