There are significant regional differences in levels of energy use and related GHG emissions from the buildings sector. Table 3.4 presents 1995 buildings sector’s fuels, electricity, primary energy, and CO₂ emissions and historical growth rates for the 1971 to 1990 and 1990 to 1995 periods for four regions (Price et al., 1998, 1999). Figure 3.4 provides a graphical presentation of the data on primary energy use in buildings, with the fourth region (Rest of World) desegregated into Middle East, Latin America, and Africa. Three very important trends are apparent:

• Developed countries have by far the largest CO₂ emissions from the buildings sector and have exhibited a relatively steady long-term trend of annual primary energy growth in the 1.8% to 1.9% range (with lower growth through 1985 and higher growth thereafter).
  
• Since the late 1980s, energy use and related CO₂ emissions from buildings in the developing countries, particularly in the Asia–Pacific region, have grown about five times as fast as the global average (and more than twice as fast as in developed countries).
  
• The growth rate of buildings’ energy use globally has declined since 1990 because of the economic crisis in the EITs. The world other than the EITs continued its long-term trend (1971-1995) of annual energy growth in the 2.8% to 2.9% range.

Table 3.4: Buildings sector 1995 fuel, electricity, primary energy, CO2 emissions, and average annual growth rates (AAGRs) for 1971 to 1990 and 1990 to 1995 by region (Price et al., 1998, 1999).
	Fuels				Electricity				Primary energy				CO2 emissions
	1995 Energy (EJ)	AAGR 1971- 1990	AAGR 1990- 1995		1995 Energy (EJ)	AAGR 1971- 1990	AAGR 1990- 1995		1995 Energy (EJ)	AAGR 1971- 1990	AAGR 1990- 1995		1995 Energy (EJ)	AAGR 1971- 1990	AAGR 1990- 1995
Developed Countries	25.45	-0.7%	0.7%		14.21	4.5%	2.7%		68.51	1.8%	1.9%		958.46	0.8%	0.9%
Countries with Economies in Transition	11.98	3.4%	-6.4%		1.39	6.6%	-7.9%		16.19	4.1%	-6.8%		319.83	2.3%	-3.0%
Developing Cos. In Asia-Pacific	7.34	4.3%	1.5%		1.85	10.4%	10.5%		12.93	5.7%	4.8%		291.62	6.7%	4.7%
Rest of World	5.14	6.2%	0.5%		2.31	8.2%	6.7%		12.15	7.1%	3.8%		162.32	6.0%	5.3%
World	49.91	1.3%	-1.2%		19.76	5.3%	2.6%		109.78	2.9%	0.8%		1732.23	2.0%	1.0%
Note: Data sources are IEA, 1997a; IEA, 1997b, IEA, 1997c and BP, 1997. For the EIT region only, energy data from British Petroleum were used instead of IEA data. Thus, primary energy and CO2 emissions for the EIT region cannot be compared. For a more detailed description of the data, see Price et al., 1998, 1999.

Between 1971 and 1990, global primary energy use per capita in the buildings sector grew from 16.5GJ/capita to 20GJ/capita. Per capita energy use in buildings varied widely by region, with the developed and EIT regions dominating globally. Energy use per capita is higher in the residential sector than in the commercial sector in all regions, although average annual growth in commercial energy use per capita was higher during the period, averaging 1.7% per year globally compared to 0.6% per year for the residential sector.

Energy consumption in residential buildings is strongly correlated with household income levels. Between 1973 and 1993, increases in total private consumption translated into larger homes, more appliances, and an increased use of energy services (water heating, space heating) in most developed countries (IEA, 1997d). In developed countries, household floor area increased but household size dropped from an average of 3.5 persons per household in 1970 to 2.8 persons per household in 1990. These trends led to a decline in energy use per household but increased residential energy use per capita (IEA, 1997d).

In the commercial sector, the ratio of primary energy use to total GDP as well as commercial sector GDP fell in a number of developed countries between 1970 and the early 1990s. This decrease, primarily a result of increases in energy efficiency, occurred despite large growth in energy-using equipment in commercial buildings, almost certainly the result of improved equipment efficiencies. Growth in electricity use in the commercial sector shows a relatively strong correlation with the commercial sector GDP (IEA, 1997d).

Space heating is the largest end-use in the developed countries as a whole and in the EIT region (Nadel et al., 1997), although not as important in some developed countries with a warm climate. The penetration of central heating doubled from about 40% of dwellings to almost 80% of dwellings in many developed countries between 1970 and 1992 (IEA, 1997d). District heating systems are common in some areas of Europe and in the EIT region. Space heating is not common in most developing countries, with the exception of the northern half of China, Korea, Argentina, and a few other South American countries (Sathaye et al., 1989). Residential space heating energy intensities declined in most developed countries (except Japan) between 1970 and 1992 because of reduced heat losses in buildings, lowered indoor temperatures, more careful heating practices, and improvements in energy efficiency of heating equipment (IEA, 1997d; Schipper et al., 1996).

Water heating, refrigeration, space cooling, and lighting are the next largest residential energy uses, respectively, in most developed countries (IEA, 1997d). In developing countries, cooking and water heating dominate, followed by lighting, small appliances, and refrigerators (Sathaye and Ketoff, 1991). Appliance penetration rates increased in all regions between 1970 and 1990. The energy intensity of new appliances declined over the past two decades; for example, new refrigerators in the US were 65% less energy-intensive in 1993 than in 1972, accounting for differences in size or performance (IEA, 1997d; Schipper et al., 1996). Electricity use and intensity (MJ/m²) increased rapidly in the commercial buildings sector as the use of lighting, air conditioning, computers, and other office equipment has grown. Fuel intensity (PJ/m²) declined rapidly in developed countries as the share of energy used for space heating in commercial buildings dropped as a result of thermal improvements in buildings (Krackeler et al., 1998). Fuel use declined faster than electricity consumption increased, with the result that primary energy use per square meter of commercial sector floor area gradually declined in most developed countries.

The carbon intensity of the residential sector declined in most developed countries between 1970 and the early 1990s (IEA, 1997d). In the service sector, carbon dioxide emissions per square meter of commercial floor area also dropped in most developed countries during this period in spite of increasing carbon intensity of electricity production in many countries (Krackeler et al., 1998). In developing countries, carbon intensity of both the residential and commercial sector is expected to continue to increase, both as a result of increased demand for energy services and the continuing replacement of biomass fuels with commercial fuels (IEA, 1995).

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