Conservation and Efficiency

A number of changes in technology, policy, and human behavior will reduce energy demands, with benefits or at most small costs for economic productivity. These influence the factor e (primary energy per unit economic product) in equation (3). Examples include:

• more efficient appliances (light-emitting diodes, low-power computers, . . .);

• more efficient indoor environments (passive lighting, heating, cooling, insulation . . .);

• urban microclimate design to minimize energy demand in extreme weather conditions (for example, using trees to lessen both heating and cooling demands);

• better urban planning (improving public transport, shortening travel distances, . . .);

• shifts toward diets that require less energy inputs (shifting diets toward vegetarianism).

Technological changes that will reduce the carbon intensity of fossil-fuel energy generation (factor i in equation (3)) include

Table 6.2. Assessment of positive and negative climate, economic, environmental, and sociocultural impacts associated with mitigation strategies

Impact

Climate change Environ- Socio-

and greenhouse Economic mental cultural

Conservation and efficiency More efficient appliances More efficient indoor environments More efficient automotive transport Better urban travel planning Urban microclimate design Better use of fossil fUels Cogeneration Changes to diets Non-fossil-f Hydropower

Solar power

(+ ++)

(-)

(+ ++) and (-)

?

Wind power

(++)

(+) and (-)

(+ ++) and (-)

(+) and (-

Bioenergy

(+ + +) and (—)

(+) and (-)

(+ + +) and (—)

(+) and (--

Geothermal power

(+)

?

(++) and (-)

?

Nuclear energy

(+ ++)

(++) and (--)

(++) and (---)

(--- )

Land-based options

Afforestation, reforestation, and

(++) and (-)

Incentives

(++) and (-)

(++) and (-

land restoration

needed

Reduction of net deforestation

(+++)

Incentives needed

(++)

(++)and(-

Forest management and fire

(+) and (-)

(+) and (-)

(++) and (-)

?

suppression

Changing agricultural management

(++)

(++) and (-)

(++) and (--)

?

Non-CO2 mitigation from land

(++)

(++) and (-)

(++) and (-)

?

biosphere

Bioengineering solutions

?

(++) and (--)

(+) and (---)

(-- )

Biological sequestration in the oceans

Ocean fertilization

(++) and (--)

?

(-- )

(--- )

CO2 disposal on land and oceans

C separation with ocean storage

(+ + +) and (—)

?

(-- )

(--- )

C separation with geological storage (+ + +) and (—)

?

(-- )

(-)

Note: Symbols (+), (++), and (+++) indicate minor, moderate, and major positive impacts (benefits); likewise,

(—), (—), and (---) indicate minor, moderate, and major negative impacts (costs). Where distinct benefits and costs occur, these are indicated separately. Impacts in the climate change and greenhouse area refer to technical potential, indicated as minor (< 0.3 PgC y-1), moderate (0.3 to 1 PgC y-1), and major (> 1 PgC y-1). A question mark indicates that insufficient information is available to make a judgment.

Note: Symbols (+), (++), and (+++) indicate minor, moderate, and major positive impacts (benefits); likewise,

(—), (—), and (---) indicate minor, moderate, and major negative impacts (costs). Where distinct benefits and costs occur, these are indicated separately. Impacts in the climate change and greenhouse area refer to technical potential, indicated as minor (< 0.3 PgC y-1), moderate (0.3 to 1 PgC y-1), and major (> 1 PgC y-1). A question mark indicates that insufficient information is available to make a judgment.

• more efficient automotive transport (hybrid vehicles that electrically recover lost mechanical energy, use of smaller cars rather than sports utility vehicles in cities, . . .);

• better use of fossil fuels (natural gas, highly efficient coal combustion); and

• cogeneration (recovery and use of low-grade heat from electric power stations, usually with smaller and more distributed power stations).

The technical potential for gains in energy efficiency from these options are large, in many cases from tens to hundreds of percentage points on a sectoral basis, and in most cases the technology is readily deployable (Hoffert et al. 2002; Edmonds et al., Chapter 4, this volume). As a group, these options have significant environmental and socio-cultural benefits, including lower urban air pollution, more efficient urban transport networks, more congenial and livable cities, and improvements to population health. Some involve changes to lifestyles (such as reducing car sizes) that may be seen as socio-cultural drawbacks. They also involve some transfers of economic power (for instance, away from oil suppliers), although many oil companies, particularly in Europe, are turning this change to advantage by repositioning themselves as energy service providers, including renewables and conservation.

Because of the magnitude and generally rapid uptake time of these mitigation options, and also recognizing the significant collateral benefits and minimal costs, many future scenarios include significant continuing mitigation from this area. Although scenarios vary widely, it is common to assume improvements in energy efficiency in the order of 1 percent per year while maintaining economic growth of 2—3 percent per year (Edmonds et al., Chapter 4, this volume; Figure 6.1). A key question is whether these uptake rates can be improved.

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