Energy use in U.S. and European homes is predicted to flatten, for the most part. But it will soar in developing and middle-income countries. The main culprit, according to new research from the University of California, Berkley, is air conditioning.
In China, sales of air conditioners have nearly doubled in the last five years, with more than 60 million units sold in 2013 alone.
Using data from Mexico, researchers at UC Berkley’s Haas School of Business built a model that took into account the relation between climate, income, and air conditioning.
When accounting for increases in incomes and expected higher temperatures, they found the number of homes with air conditionings would rise from 13 percent today to more than 70 percent at the end of the century.
“This is mostly good news,” Lucas Davis, lead author of the paper and professor at the Hass School of Business, wrote in a blog post. “Air conditioning will bring relief to the more than three billion people who live in the tropics and subtropics.”
The problem, however, is that meeting the new demand will require intensive investment in electricity grids in places where it is already badly needed, such as India and southeast Asia.
In the United States, which uses more air conditioning than the rest of the world combined, most of the grid is sized to meet the few days a year when coolers are cranking at full blast under sweltering temperatures.
This has led to a grid that runs inefficiently most of the year. Some technologies have been adopted more widely in recent years to help curb demand when it’s at its highest, such as remotely controlling air conditioner compressors, but those will have to become commonplace in other areas of the world if air conditioning is widely adopted.
In India there are three times as many days that are warm enough to warrant air conditioning use as there are in the United States. That brings India’s demand for cooling to 12 times what it is in the United States, according to the researchers. Indonesia, Thailand and the Philippines all have even more such “cooling degree days” than India. Within just a few decades, the model shows “near universal saturation” of air conditioning use, according to the Berkeley team.
Grids need enough generation available to power all of these air conditioners. But in India, there is not even adequate generation for the electricity load today. But there is also an opportunity to invest in efficient air conditioners and in generation sources that will best match the growth in air conditioner use.
The southeast United States could be somewhat instructive for other countries. It has seen electricity use for cooling jump 43 percent in the past 20 years, and the region’s electricity use is growing as people build bigger homes with central air conditioning. Unlike some other regions of the United States, however, it is relatively devoid of strict state energy efficiency standards that exceed federal efficiency standards or other standards that drive the uptake of more efficient AC units.
In China, efficiency standards for air conditioners have become more strict in the past decade, and could continue to do so. As a potential supplier to Southeast Asia, the minimum efficiency of Chinese products could be important for efficiency across Asia.
Another concern with the rising use of air conditioning is the issue of matching generation to demand. Solar power peaks earlier than cooling use, but it can be close. So precooling homes and businesses while solar output is at its highest could help mitigate how much power an air conditioning unit may need from the grid in the late afternoon.
There is also an opportunity for more distributed solutions, such as air conditioners that run at least in part on solar power directly. Advances in technologies such as these, along with energy efficiency could “reduce the energy consumption impacts substantially,” Davis wrote.
But the time is now to make decisions about the cost of energy and what technologies should be available, he added. “We need an ‘all-hands-on-deck’ approach including aggressive funding for innovation, efficient pricing of energy, and evidence-based environmental policies,” he wrote. “We need efficient markets if we are going to stay cool without heating up the planet.”