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Will AC Put a Chill on the Global Energy Supply?

Michael Sivak

New Biggest Users?

2013-09MacroSivakF3.jpgClick to Enlarge ImageThree notable findings emerged from studying the potential energy demand for air-conditioning in these 170 countries. First, eight countries have the potential to exceed the United States’ yardstick of high air-conditioning usage, because of their warm climates and significant populations. Furthermore, the top three could surpass the United States by substantial amounts: India, China, and Indonesia by factors of 14, 5.2, and 3.1, respectively, if they adopt American standards of cooling.

Second, among the top 25 countries, 22 are below the World Bank income limit for developing countries. Hence, the current cooling demand there is nowhere near the possible peak.

Third, the total demand in the 169 countries analyzed (excluding the United States) has the potential for cooling-energy demand that is 45 times greater than in the United States today. More broadly, the future demand in all countries of the world outside of the United States—the United Nations currently lists 229 of them—has the potential to exceed the demand in the United States by a factor of 50.

Several caveats are in order. Cooling degree days, being a temperature measure, does not represent all factors that are relevant to the potential demand for cooling. Some other considerations include the extent of local cloud cover, humidity, the amount of interior space to be cooled per person, and differences in dwelling construction and their effects on thermal insulation. Variations in the energy efficiency of air conditioners across countries were not included in this analysis. In addition, cultural differences in the tolerance of hot temperatures and in environmental responsibility were beyond the scope of this study.

Because of these limitations, the present calculations should be viewed only as first approximations of the potential future energy demand for air-conditioning. Nevertheless, it is clear that the global energy demand for air-conditioning will grow substantially as nations become more affluent, with the consequences of climate change potentially accelerating the demand. This trend will put additional strain not only on global energy resources but also on the environmental prospects of a warming planet.

Several institutions have recently made major technical advances in the design of more energy-efficient air conditioners. For example, developments at the National Renewable Energy Laboratory suggest that efficiency improvements of 20 to 70 percent are possible compared to current models of air conditioners. Changes in housing design and urban planning are also needed, but such changes require more time and resources for implementation. The data I presented here emphasize the urgency to accelerate progress in all relevant areas.

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