Chapter 3 - Energy Use and Urban Environmental Quality

Energy use—particularly the use of energy from fossil fuels—has the most significant impact on environmental quality both within and beyond a city’s borders. It can deplete non-renewable resources and produce emissions that contribute to smog and other local environmental problems, as well as global environmental problems such as climate change.

Figure 6 presents primary energy use by sector, while Figure 7 shows corresponding shares of GHG emissions. Primary energy use shown in Figure 6 amounts to 11 105 petajoules; GHG emissions shown in Figure 7 total 592 MT.

The production of energy (fossil fuel production and power generation) consumes a significant amount of energy—one quarter of all energy used—and produces more than one third of GHG emissions. Because there are little or no data to indicate what share of energy is produced in cities, point-source emissions from energy production are not considered to be a characteristically urban environmental issue, and therefore did not fall within the scope of the Task Force’s work. These emissions can be reduced, however, through the adoption of more sustainable forms of energy production suited to an urban environment, such as community energy systems.

Industrial use (including both building-related energy uses and energy used for industrial processes) accounts for the largest share of energy use. Energy use and emissions associated with industrial processes were also not considered for the Task Force’s purposes to be characteristically urban environmental issues.

Transportation is the next most significant sector, accounting for 22% of primary energy use and 29% of GHG emissions. The residential and commercial sectors (the latter includes offices and institutions) account for 13% and 9% respectively of energy use, and 9% and 5% respectively of GHG emissions.

Energy use broken down by end-use—that is, excluding the production of energy—is shown in Figure 8; Figure 9 shows the corresponding shares of GHG emissions. Total energy use shown in Figure 8 amounts to 8164 petajoules and emissions shown in Figure 9 total
473 MT.

Energy use for transportation

Transportation contributes disproportionately to GHG emissions, partly because the energy used to power vehicles is usually generated from fossil fuels. In contrast, energy used in the commercial and residential sectors—primarily to heat, cool and light buildings—may come from cleaner sources such as natural gas or hydroelectricity.

More than half (57%) of the energy used for transportation is used to move passengers; cars account for the greatest share of this energy use, followed by light trucks (including SUVs), with buses a distant third. Freight transport accounts for 40% of transport energy use.

Overall, transport energy use grew 21.5% between 1990 and 2000. Although energy used by cars declined by 15.4% during this decade, freight transportation used 34% more energy and energy use by light trucks increased by 85.2% (Figure 10).

The main factors in transport energy use are distance travelled, vehicle loading and mode, each of which is influenced by urban form.

Travel patterns, and therefore the amount of energy used for transportation in urban areas, vary greatly with urban form. The density of urban areas, urban structure, mixing of uses or lack thereof, and street patterns all affect the number, length and mode of trips (e.g., walking, cycling, taking transit or driving a car).

Total vehicle-kilometres travelled, for example, can vary greatly according to location within the city (Figure 11).

Energy use for buildings

By end-use, energy used for residential, commercial and industrial buildings is responsible for the lion’s share of GHG emissions (see Figure 9; note that the energy calculated for the industrial sector includes energy used for industrial processes). Especially in the residential and commercial sectors, most building energy is used for water heating, space heating and space cooling. These three end-uses account for more than 80% of all energy used for residential buildings.

In Canada, building energy use grew more moderately than transport energy use from 1990 to 2000. Although the transport sector and the commercial sector (offices and institutions) have each increased their energy use by 22% since 1990, energy use in the residential sector in the same period rose by only 6.8%.

The main factors influencing building energy use include building construction (closely related to the age of the building), building shape and orientation (closely related to building type), internal climate characteristics (e.g., usual thermometer settings) and internal activity. Also, building energy use varies with urban form. For example, townhouses and apartments, which are more prevalent in urban areas, tend to be more energy efficient than single detached homes.¹⁸

Indeed, evidence suggests that overall energy use is inversely related to the density of development:¹⁹ more compact, mixed-use cities, which support greater use of sustainable forms of transportation and less energy-intensive building types,²⁰ tend to use less energy.

A majority of participants in the Urban Sustainability Program determined that urban form is one of the most important drivers of urban environmental quality. It influences energy use for transportation, which is GHG-intensive and growing rapidly, particularly for light trucks, SUVs and freight transportation. Urban form also influences the energy efficiency of buildings, which are significant energy users and contributors to GHG emissions. And urban form influences the loss or disruption of agricultural lands, sensitive environmental areas, natural habitats and water quality.

Endnotes

16 Emissions from agro-ecosystems, waste, land use and propellants/anaesthetics, as well as emissions of hydrofluorocarbons, were excluded because they collectively represent only 88 MT of GHG emissions (compared with 680 MT for all contributors in the figure) and are mostly from non-urban sources (63 MT of the 88 MT come from agro-ecosystems).

17 Toronto Public Health Department, Air Pollution Burden of Illness in Toronto, May 2000; Toronto Public Health Department, Toronto Air Quality Index Health Links Analysis, October 2001; Ontario Medical Association, Illness Costs of Air Pollution, July 2000.

18 At least for new stock. For older stock, apartments can be more energy intensive than single detached homes.

19 International Council for Local Environmental Initiatives, Saving the Climate, Saving the City: Briefing Book on Climate Change and the Urban Environment, 3rd ed. Toronto, 1995.

20 See for example, Peter Newman and Jeffrey Kenworthy, Sustainability and Cities: Overcoming Automobile Dependence. Washington, DC: Island Press, 1999.

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