If your electric bill shocks you now, just wait until climate change kicks in.
A warmer world will mean more demand for air conditioning, putting more of a strain on power plants and the network of wires that transmit electricity around the United States. And building the plants needed to carry that load could cost U.S. utilities between $70 and $180 billion over the coming decades, depending on how much the world reduces its output of carbon dioxide and other gases blamed for nudging up global temperatures.
That's the conclusion of a new study by researchers in California and Michigan, who used data from American power grid operators and computer models of expected emissions to come up with their cost estimate.
"It points to climate change mitigation being more valuable than we thought, just because climate change adaptation is going to be more expensive than we thought," said Catherine Hausman, a University of Michigan economist who co-authored the study.
The projected increases aren't evenly spread around the country. The Northwest, where electricity is more commonly used for heat, is expected to see less consumption as temperatures get warmer.
But in the business-as-usual scenario developed by climate scientists, the number of days that utilities have run at peak capacity to meet expected demand balloons more than fifteenfold by the end of the century. In places like Texas, that means going from four days a year when utilities have to crank their plants up to 11 to as many as 65.
If countries manage to cut emissions moderately in the coming decades, the number of peak demand days only quadruples. But that still means an average increase in demand of about 3 percent a year, and 7 percent on peak days; in the worst-case scenario, peak demand could spike as high as 18 percent.
"We have time to figure it out, but the solutions I would currently envision for figuring this out will cost money," Hausman said.
The study was published this month in the research journal Proceedings of the National Academy of Sciences.
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The Paris climate accord, which went into effect in November, calls for steep cuts in emissions in order to keep global average temperatures from warming more than 2 degrees Celsius (3.6 Fahrenheit) above the late 19th century average by 2100. The moderate cuts might be enough to keep the planetary thermostat at or slightly above that mark, beyond which scientists warn climate change could become catastrophic. Without them, the world may see average temperatures topping 4 C - fueling more intense storms, deeper droughts and raising sea levels that will displace millions of people, while making it harder to grow crops and fight diseases.
To complicate things further, Hausman said the additional demand she foresees is likely to be met by burning more natural gas, rather than renewable electric sources like solar and wind. Power company executives are making long-term decisions based on what's at hand now, and the technology to store power from renewables at large scale isn't available yet, she said.