Even if Ontario's current rate of electricity production were to be generated entirely from renewable resources or nuclear energy, and if an equivalent amount of other energy could be realized from cogeneration, deep lake-water cooling, and passive solar means, the total available energy would be less than half of recent use (see Figure 1). There still would be substantial dependence on what could be increasingly expensive oil and natural gas, unless strong measures to reduce energy use were put in place.
High energy prices themselves contribute to reductions in energy consumption. The long-term price elasticity of demand for gasoline is perhaps around -0.6, meaning that for every percentage point of price increase there is a reduction in consumption by 0.6%.40 Some of this is achieved through purchase of more fuel-efficient vehicles. Some is achieved through travelling by different modes or by reducing the amount of motorized travel.
Elements of the Smart Growth policy could be critical to the way in which individuals and businesses are able to reduce their energy consumption for transportation through travelling by different modes and by reducing the amount of motorized travel. Travelling by different modes requires availability of more public transit, which in turn requires settlements of a size and density sufficient to support transit. Travelling fewer motorized kilometres again requires denser settlements, as well as amenities for pedestrians and cyclists.
Energy use for the movement of people is closely related to urban density. This is shown in Figure 11, in which the energy use data shown in Figure 6 are plotted against residential densities.41 The 52 urban regions fall on or close to a straight line whose slope suggests that a given relative difference in density is associated with a somewhat smaller relative difference in energy use for the movement of people. (More specifically, the slope of the log-log plot in Figure 11 suggests that the square of the energy use is inversely associated with the cube of the density.)
Figure 11. Energy use for moving people and settlement density, 52 affluent urban regions, 1995 (log scales)
An indication of how things change within an urban region, specifically the Greater Toronto Area (GTA), is in Figure 12 and Table 2.42 Both travel mode and total distance travelled change with settlement density. Indeed, the actual differences within the GTA correspond closely to the differences between urban regions portrayed in Figure 11.43 This suggests, for example, that transport energy use in the GTA's outer suburbs could be halved by developing and redeveloping them to the density of the core ring.
Figure 12. Shares of weekday trips by residents of different parts of the Greater Toronto Area, 2001
Car ownership levels, shown for concentric parts of the GTA in Table 2, appear to be critical factor in transport energy use, for the following reason. For a given country, the number of kilometres driven per personal vehicle is remarkably constant from year to year. In Canada, for example, it changed only from 17,300 to 18,000 kilometres per vehicle between 1990 and 2000.44 Other countries show similar or greater constancy in this value. Thus, an important factor in the distance travelled by automobile in a country is the number of vehicles in use. If the number of vehicles goes up by 10% then the distance driven goes up by about 10%. It seems to be a case of "have car, will travel." It follows that strategies designed to reduce car use that do not seek to reduce car ownership may be likely to fail.
Thus, as well as increasing density and adding transit facilities, there may be a need to design communities so that living in them without a car is at least as appealing as living with a car (or living with one car rather than two per household, or two cars rather than three).
Table 2. Travel data, car ownership, and residential density in the Greater Toronto Area, 2001
|
|
Core |
Core ring |
Inner Suburbs |
Outer suburbs |
|
Number of motorized trips per day per person |
2.08 |
2.31 |
2.34 |
2.67 |
|
Distance travelled by transit (km. per person) |
4.4 |
4.5 |
4.5 |
3.3 |
|
Distance travelled by automobile (km. per person) |
7.5 |
11.6 |
15.3 |
24.8 |
|
Households with no car |
51% |
29% |
17% |
5% |
|
Annual energy use for transport (MJ per person) |
12,300 |
17,600 |
22,300 |
33,600 |
|
Residential density (persons per square km. of urbanized area) |
9,900 |
6,100 |
3,100 |
2,500 |
Information about how energy use for freight transport varies with urban form is not available. Distance travelled could vary inversely with density, as it does for the movement of people, but other factors may apply differently. There is at present no equivalent in freight transport to the greater opportunities to provide and use public transport that are available where densities are higher. Conceiving, designing, and implementing such opportunities will likely become a major challenge as energy constraints become more evident.45
As noted in connection with Figure 1, more energy is used in Ontario for space heating and cooling than for the movement of people. However, households and businesses spend considerably less on these functions because there is much less tax on energy used for heating and cooling. Energy use in buildings varies with many factors--including building size, type, shape, age, orientation, composition, use, maintenance record, immediate location, etc.--that for the most part obscure relationships with settlement density.
Perhaps the clearest relationship is the obvious one: other things being equal, the amount of heating and cooling required is closely related to the floor area that is being used. Thus, reductions in per capita in-building energy use can usually be achieved by reducing the amount of floor space used per person.
What is also clear is that buildings can be designed to maintain comfort in winter with no or almost no use of added heating. This can be easier for large buildings, e.g., the headquarters building of Ontario Power Generation (OPG) in Toronto, which relies mainly on adroit capture and use of heat from bodies, lighting, and machines. There are several examples of smaller Ontario buildings, such as the home of Anthony and Mary Ketchum in Hockley Valley, which is not on the electrical grid and relies on heavy insulation, solar heating, earth energy, and occasional use of a wood stove.46 Summer cooling is a challenge for larger buildings, which can have large amounts of internally produced heat to offset.
Upgrading existing buildings to use no or little energy for space heating and cooling can be a major undertaking,47 but almost every building can benefit from attention to unnecessary heat loss in winter and unnecessary heat gain in summer. As energy prices rise, there will be more incentive to upgrade buildings. Energy consumption will become a major criterion in the purchase of new homes and other buildings. Also, many buildings will be more intensively used, to reduce per-person energy costs. This could have profound implications for the Smart Growth strategy.
A comprehensive Smart Growth strategy could facilitate reduction of energy consumption within buildings by mandating low-energy-use designs and providing incentives for upgrading, funded by taxes on fossil-fuel energy delivered to buildings (analogous to the use of gasoline taxes to fund transit, an increasingly appealing strategy across Canada).
Increasing settlement densities alone is likely to have much less effect on in-building energy use than on transport energy use.