Table 3.9 Energy Consumption in Cities: Key End Use Activities and

residential air-conditioning and larger appliances. Although cities generally do not control appliance effi ciency, and equipment standards are usually under the purview of national governments, cities may adopt incentive programs to encourage the use of more effi cient appliances.

Though industries form part of the urban landscape, including industries in urban energy accounting may skew the understanding of city energy consumption and performance because the type and signifi cance of industries vary across cities. For consistency in cross-city energy comparisons, it may be necessary to exclude (or separate) industrial energy consumption from the typical urban energy-consumption sectors indicated in table 3.9.

For urban energy planners, it is also necessary to separate urban energy demand and consumption into key end use activities, often within the four main sector categories outlined earlier. End use activities are more or less similar across cities, although the energy type supporting specifi c end uses may vary even within a city (see table 3.9).

Excluding industrial consumption, end use energy patterns in developing-country cities, especially cities in low-income provinces or states, are skewed toward the most basic energy services, such as lighting and cooking (and space heating in cold climates). The direct use of solid fuels, such as coal and fi rewood, is common in developing-country cities and is often the main cause of indoor and ambient air pollution. This is particularly true in low-income urban areas and slums in which access to cleaner cooking fuels is limited.

Electricity is the form of energy used most extensively in cities. The share of electricity in total energy use and the amount of electricity per capita often indicate the modernity and wealth of a city. Satisfying rapidly growing electricity needs often dominates the energy agenda of developing-country cities. (At the other extreme, gasoline is exclusively used for transport.)

Energy costs are critical to understanding energy use in cities and are often a primary energy-related concern of city offi cials. Decisions on sustainable energy must be economic and fi nancial. However, the data on the costs according to energy type and on aggregate energy costs in urban sectors are often inadequate. Adequate cost information on individual end use activities and even simple data on common energy indicators are also rare (for example, kilowatt-hours per cubic meter of water

Table 3.9 Energy Consumption in Cities: Key End Use Activities and Energy Types

COMMON ENERGY TYPES USED

NATURAL GASOLINE, FIREWOOD, MAIN ENERGY END-USE ACTIVITIES ELECTRICITY GASa LPGb KEROSENE DIESEL COAL CHARCOAL

Lighting Cooking Water heating (domestic hot water) Appliances (refrigerators and so on) Home and offi ce electronics

Air conditioning Space heating (cold climate) Motorized transportation Motive power (stationary) Processing heat or steam

Source: Author compilation (Feng Liu). a. In some cities, gas supplies are still provided by coal-gasifi cation or coking facilities, but in general, town gas is no longer an attractive energy supply option in cities. b. LPG = liquefi ed petroleum gas.

delivered, tons of oil equivalent per person per mode of transport, or watts per square meter of building lighting).

Few cities in developing countries systematically track energy consumption patterns and costs. Without adequate energy consumption and cost information, cities will not be able to plan and implement sustainable energy measures eff ectively. Recent eff orts to establish an international protocol and tools to inventory urban greenhouse gas emissions are helping build a platform to facilitate improved urban decision making on sustainable energy approaches (ICLEI 2008). Besides basic accounting, a critical element of urban energy planning is the provision of information to stakeholders about the opportunities for demand management through investments in energy effi ciency, conservation programs, and alternative supplies. Simple benchmark data, such as quantifi able measures of energy use in lighting and heating, may help city managers to identify sectors that exceed norms and to plan remedial interventions. Additional supply options such as cogeneration in wastewater treatment plants or methane capture in landfi lls may also be assessed. The evaluation of such options requires tools to help cities compare their energy performance with good or best practice and understand the cost and benefi t implications. Practical decision support tools and methods for sustainable urban energy planning and management help cities quickly identify and prioritize sustainable energy actions grounded on local capacities and conditions.

Energy Supply Options and Spatial and Temporal Considerations

Modern cities are highly dependent on network-based electricity and, to a lesser extent, natural gas supplies that are connected to regional or national networks. Power plants are often located within city boundaries, but these are frequently owned or operated by regional or national electricity utilities or independent power producers.7 Developing-country cities generally aim to ensure secure and reliable access to energy supplies based on regionally integrated networks. District heating systems represent another network-based energy service common in cold climate cities, especially in China and Europe. However, they are limited to areas of a city with suffi cient building density. Supplies of solid and liquid fuels, such as coal and petroleum products, are usually decentralized; thus, users may buy fuels from diff erent producers or local distributors. The supply of transport fuels is usually vertically controlled by oil companies. In low-income countries, cities with signifi cant periurban and slum populations often rely heavily on fi rewood and charcoal as cooking fuels and, in cold climates, also as heating fuels. The fi rewood is typically supplied locally and is often collected by individual households; charcoal is usually supplied by informal service providers. As a city grows in wealth, there is a progression among households and other dispersed service points toward greater dependence on network-based energy supplies and away from the use of solid fuels (coal and fi rewood). In general, cities and urban areas are almost entirely dependent on external energy supplies; even the power plants located in cities need to import fuel.

It is possible to conceive of a city’s energy supply options and technologies along the three main energy delivery channels depicted in fi gure 3.37. In mildly cold and mildly warm climates, centralized heat supply is generally not an economically viable option and is not considered. In cold climates, electricity and centralized heat are often the focus of urban energy optimization because they may be produced together in combined heat and power plants. Cooling may be provided by using heat energy to drive a cooling system based on absorption chiller technology. Thus, district heating systems may provide cooling services in