Appendix A – Data and methodology

View the most recent version.

Data

The two principal data sources used in the study are Statistics Canada's Material and Energy Flow Accounts (MEFA), and the survey of private vehicle energy use conducted as part of the Canadian Vehicle Survey. The MEFA record in physical terms only, the flow of materials and energy, in the form of natural resources and wastes between the economy and the environment. They are linked directly with the input-output accounts, which allows the calculation of important indicators of the resource and waste intensity of economic activity. ¹ 

The biennial survey of private vehicle energy use is conducted as part of the CVS by Transportation Division, on behalf of Environment Accounts and Statistics Division (EASD). The first results of the 2007 survey have been used in this study. The CVS is a voluntary vehicle-based survey that provides quarterly and annual estimates of road vehicle activity (for example, fuel consumption and distance travelled) by vehicles registered in Canada. The survey is conducted on a sample of vehicles drawn from vehicle registration lists provided by the provincial and territorial governments. At the time of the study, the vehicle energy use data from the survey were only available for reference year 2007 (Text box: The Canadian Vehicle Survey). ² 

Other supplementary data sources such as Environment Canada's National Inventory Report, the Census of population, input-output tables, Income and Expenditure Accounts of the System of National Economic and Environment Accounts, and the Survey of Household Spending have also been used. It should be noted that, the population data used to calculate per capita emissions in the study were obtained from CANSIM. Preliminary population estimates that were available at the time of the study are subject to revisions upon subsequent data releases. As a result, any revisions in population estimates are likely to yield slightly different results. This is also true for other data series used in the study, such as the personal expenditure on motor fuels and lubricants.

Methodology

The GHG estimates by type of greenhouse gas (carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O)) were derived by adopting a methodology that is found in Environment Canada's National Inventory Report, 2009 (NIR), the Canadian government's submission to the UN Framework Convention on Climate Change. The methodology is based on the following equation used for estimating emissions for general fuel combustion, described as:

E_Category,G = FC_F,R x EF_G,F,R,T

where E_Category,G is GHG emissions by source category and by gas, FC_F,R is quantity of fuel consumed (in physical units, such as kg, L, or m³) by type of fuel and by region, EF_G,F,R,T is country specific emission factor (in physical units) by GHG, by fuel type, by region (where available) and by technology. ³ 

The household sector's energy consumption by type of fuel was compiled and converted into volume of litres. The corresponding emission factors were then applied to each fuel type, to arrive at estimates of vehicle emissions by type of greenhouse gas for each region and for each type of fuel. The results were then aggregated to arrive at the final estimates of GHG emissions, which were then converted to carbon dioxide equivalent estimates. ⁴ 

Intensity levels were calculated as GHG emissions from private vehicle operation divided by households' expenditure on motor fuels. ⁵  Intensity captures the quantity of emissions produced, measured in physical units per a unit value of household consumption, measured in constant dollar expenditure, chained (2002) dollars. In other words, it is the amount of emissions generated from a dollar's worth of personal expenditure on motor fuels. GHG emissions from private vehicle operation as a share of total GHG emissions of the household sector were also among the additional variables analyzed.

The emissions estimates in the study were developed in two stages. The first stage dealt with a time series component that covers the period 1990 to 2007, using mainly MEFA data. MEFA data were not available for the last two years (2006 and 2007) of the period under study. As a result, the emissions estimates for these two years were developed using NIR's road transportation emissions data as input in order to estimate the share of private vehicle emissions out of the total road transportation emissions published by Environment Canada. These estimates for 2006 and 2007 will be revised along with other years that are subject to revision, subsequent to the release of MEFA estimates during the next two years.

In the second stage, 2007 emissions estimates were produced for the total provincial population by income groups. Total and per capita emissions estimates by province and CMA were developed using data from the CVS. The 2007 national, provincial and CMA emissions levels from light vehicles operated by gasoline and diesel fuels were calculated by applying a ratio to split out the energy consumption of private households. This was done by using MEFA's household energy consumption estimates in terajoules for reference year 2005.

The 2007 estimates were developed based on the assumption that most privately owned and operated vehicles are classified to the light vehicle category and are operated either on gasoline or diesel. This leaves out the small percentage of privately owned and operated vehicles that are in the heavy vehicle category as well as those light vehicles operating on other fuel types. According to the CVS, in 2007, 99.6% of all the vehicles in scope for the survey operated either on gasoline or diesel fuel. As well, 96.1% of light vehicles operated on gasoline or diesel fuel. The other underlying assumption is that the ratio of use of fuel type (gasoline-to-diesel) does not significantly vary over the different geographic regions. This assumption has also been necessary in order to get around the constraints of micro data by type of fuel. As a result, the personal sector's gasoline-to-diesel ratio at the national level has been applied to the aggregate personal fuel consumption figures of each of the geographic regions addressed in the study.

Emissions per kilometre

The estimates showed that at the CMA level, model-year and vehicle-type variables were the most important indicators of vehicle emissions. Although consistent for the most part, emissions per kilometre as a variable, at times tends to produce inconsistent results for high-traffic-density CMAs such as Toronto or Montreal. For example, if we hold other factors constant, a vehicle driven only 10 kms in high-traffic-density area in Toronto is more likely to consume more fuel and therefore produce more emissions than a vehicle driven 15 kms in a low-traffic-density CMA such as Kingston.

Variations in emissions per kilometre among CMAs originate mainly from two factors that affect the total fuel consumption estimate, the FCR (fuel consumption ratio) and the size of the vehicle population. The FCR varies by model year, vehicle body type, and whether the vehicle is used for city or highway driving, among other things. As a result, two CMAs with the same size of vehicle population and kilometres driven can produce two very different levels of emissions depending on their respective fleet composition (in terms of model year and body type of the vehicles) and proportion of city and highway kilometres driven.

The fuel consumption estimates in this paper were obtained from the CVS as actual volumes of fuel consumptions reported by the drivers as opposed to fuel consumption estimates modelled based on FCR, vehicle kilometre, and vehicle population as described in the NIR. ⁶  Comparison of fuel consumption estimates of the various data sources and their respective methodologies is therefore outside of the scope of this paper. ⁷ 

Comparison of methodological applications with Environment Canada's National Inventory Report, 1990-2007

Although the methodology is similar to the one used by Environment Canada in the NIR, the differences in the emissions estimates of the two studies are mainly due to distinctions in data sources used and coverage of the vehicle population. In this study, the emissions estimates for the provinces and CMAs were developed using survey based fuel data on actual fuel consumption figures (on gasoline and diesel only) reported by respondents who owned or leased the vehicles in scope for the survey. In the NIR, however, estimates of emissions were produced using fuel data on all vehicle fuel types derived from observed trends (at least for the years 2003 to 2007), along with fuel conversion factors (FCRs) and data on kilometres driven. ⁸ 

Our estimates also represent the emissions of the personal sector while the NIR estimates represent emissions from vehicles in the total economy. The difference in the coverage of the vehicle population is also partly due to the variation in the definition of light vehicles. Light-duty vehicles are defined in the CVS as those vehicles with gross vehicle weight rating (GVWR) below 4.5 tonnes, whereas in the NIR, light vehicles and trucks are those with a GVWR below or equal to 3.9 tonnes.

Environment Canada's methodology also accounts for the deterioration of catalytic converters that affect tail pipe emission rates of CH₄ and N₂O. This was done by disaggregating the vehicle population and applying technology-specific deterioration rates to light-duty vehicles and trucks with catalytic-controlled technologies. ⁹  In our study, the MEFA based time series estimates (for Canada) were built by taking the effect of deterioration of catalytic converters into account. However, the CVS based estimates (for the provinces and CMAs), did not include any adjustments to that effect. This is because the CVS does not collect data on the availability of tail pipe emission controlling technologies such as catalytic converters on private vehicles. Instead, until reliable information is available to account for the deterioration of catalytic converters, this study used the most conservative emission factors for CH₄ and N₂O among those published by EC (for each type of emission control technology).

Material and Energy Flow Accounts of the Canadian System of Environmental and Resource Accounts

The Material and Energy Flow Accounts (MEFA) are organized around the accounting framework of the Input-Output Accounts of the Canadian System of National Accounts (CSNA). The MEFA also share their classifications of industries, households and governments with the Input-Output Accounts. The methods used to estimate flows of resources and wastes in MEFA are described below.

Energy

Reliable, quantitative estimates of annual energy use are available for the major energy-using industries directly from Statistics Canada surveys. Little more is required to incorporate these data into the MEFA than to aggregate them according to the MEFA classifications of industries and energy commodities. Eleven energy commodities are represented in the accounts: coal, crude oil, natural gas, liquid petroleum gases, electricity, coke, motor gasoline, diesel fuel, aviation fuel, light fuel oil and heavy fuel oil. Both the consumption of these commodities for their energy content (the combustion of gasoline in motor vehicles for example) and as material feed stocks (natural gas used as a raw material in fertilizer production for example) are measured in the accounts. The 11 energy commodities represented in the MEFA match exactly with those represented in the Input-Output Accounts. Moreover, the Report on Energy Supply Demand in Canada (RESD) (Statistics Canada, Catalogue no. 57-003-X) provides benchmark estimates of total annual availability for each energy commodity. Total consumption of each of the 11 energy commodities represented in the MEFA must be equal to the reported domestic use in the RESD.

In the case of energy consumers for which suitable quantitative data are not directly available, an alternative estimation method based on the Input-Output Accounts is used. The use of the Input-Output Accounts first requires that the available quantitative data be summed for each energy commodity. These amounts are then subtracted from total availability by commodity (from the Report on Energy Supply Demand in Canada), leaving a residual quantity of unallocated availability for each commodity. These residual quantities represent consumption by those consumers for which no direct quantitative data are available. The equivalent value of their energy consumption is calculated from the Input-Output Accounts by distributing the residual value according to the dollar value of purchases in the Input-Output Accounts.

Greenhouse gases

Statistics Canada's energy account and Environment Canada's national inventory of greenhouse gas emissions are used as the basis for the estimation of the greenhouse gas emissions data (carbon dioxide, methane and nitrous oxide) included in the MEFA.

Emissions of carbon dioxide are the most straightforward of the greenhouse gases to measure. Emissions of this gas are primarily related to the combustion of fossil fuels. Environment Canada calculates a single set of emission factors that accurately express the quantity of carbon dioxide produced per unit of fossil fuel burned (in tonnes of CO₂ per unit of fuel). These factors are combined with MEFA energy data to estimate carbon dioxide emissions from fossil fuel.

Estimates of methane and nitrous oxide emissions from on-road transportation are taken from the results of a computer simulation model known as MGEM (Mobile Greenhouse Gas Emissions Model) adapted by Environment Canada from the Mobile model originally developed by the U.S. Environmental Protection Agency. MGEM produces national and provincial emissions estimates based on the national vehicle fleet, fuel consumption ratios, kilometres travelled and other relevant factors.

The incorporation of data from MOBILE into the MEFA is not straightforward due to lack of appropriate vehicle registration data related to vehicle ownership by industry. Instead, implicit methane and nitrous oxide emissions factors are derived from the information in the NIR, and these are applied to industries and households based on the types of vehicles commonly used in each sector.

Emission factors for non-combustion uses of fossil fuels (for example, feed stocks) and industrial processes have also been developed by Environment Canada to estimate their associated carbon dioxide emissions. Estimates of the emissions of methane and nitrous oxides are also included in the MEFA. It is possible to aggregate the emissions and express them as a single value with an index known as global warming potential (GWP). GWP measures the heat-trapping potential of each greenhouse gas. Carbon dioxide, the least effective of the gases at trapping heat, is arbitrarily assigned a GWP of one; other gases are assigned values in proportion to their heat-trapping potential relative to that of carbon dioxide (21 for methane and 310 for nitrous oxide). GWP is used in the MEFA to weight and aggregate emissions of carbon dioxide, methane and nitrous oxide. Aggregate greenhouse gas emissions for industries, households and governments are expressed in terms of "carbon dioxide equivalent" emissions. ¹⁰