by the University of Michigan
ANN ARBOR, Mich.— Developing countries use proportionally less energy than industrialized nations, but large cities like Madras and Bangkok are helping to fuel global energy demand, according to a University of Michigan study.
Thirty-eight of the world’s 50 largest metropolitan areas are located in countries with emerging economies and most of them are located in warm-to-hot climates.
“Using energy to cool houses and apartments is not yet common in developing countries,” said Michael Sivak of the U-M Transportation Research Institute. “However, as individual income in developing countries increases, it is likely that so will the use of air conditioning in hot climates.”
In a new study published in the journal Energy Policy, Sivak examined the combined energy demand per person for residential heating and cooling in the world’s 50 largest metropolitan areas.
His analysis used data on “heating and cooling degree days”—units that relate to the amount of energy needed to heat and cool buildings—to produce a combined index of total energy demand for climate control. One heating (cooling) degree day occurs for each degree the average daily outdoor temperature is below (above) 65 degrees Fahrenheit.
Sivak says that among the world’s 50 largest cities, the top 13 in terms of cooling degree days are located in developing countries, such as India, Thailand, Vietnam, Philippines, Indonesia, Pakistan, Bangladesh and Nigeria. All but two of the top 30 are in these and other developing nations.
The warmest metropolitan area in developing countries—Madras—has 1.6 times the cooling degree days of Miami, the warmest city in developed countries. The potential cooling demand for another Indian city—Mumbai—is about 24 percent of the demand of the entire United States.
Currently, nearly 90 percent of housing units in the United States have central or room air conditioning, but only 2 percent in India do.
“Whether the potential cooling demand in developing countries will translate into energy consumption for cooling on the scale of the United States or greater is not clear,” he says. “Differences in energy infrastructure, size and occupancy density of buildings, sustainability concerns, desirable temperature and diurnal use of air conditioning will influence the energy use for cooling in developing countries. Nevertheless, the potential for a huge increase in energy use remains.”
Overall, among the largest cities in the world, four cold-weather metropolitan areas use the most energy (mostly heating, but some cooling, as well): the Russian cities of St. Petersburg and Moscow and the North American cities of Toronto and Chicago (the only two cities in industrialized nations among the top 10).
The rest of the top 10 include warm-weather cities Madras; Bangkok; Karachi, Pakistan; Ho Chi Minh City, Vietnam; and the Chinese cities of Beijing and Tianjin, which have more seasonal weather.
