As climate-driven warming leaves American cities sweating, urban buildings may sustain much more frequent surges in peak electricity usage over the coming decades, a new study has found.  

The energy required to cool U.S. buildings could increase by 13.8 percent for each degree of warming on average, according to the study, published on Wednesday in Nature Communications. 

Giant urban footprints: Residential and commercial buildings in U.S. cities today consume about 39 percent of the country’s energy, the study authors noted. 

• They are also responsible for about 28 percent of the nation’s greenhouse gas emissions, per the U.S. Energy Information Administration.
  
  
• Today, fossil fuels account for about 40 percent of all building energy consumed in U.S. urban city centers.    

Figuring out the future: Given the dynamic effects of climate change, however, the researchers understood that these figures would not necessarily apply to the buildings of decades to come. 

“Understanding their future energy use is very important for developing climate change mitigation strategies,” lead author Chenghao Wang, an assistant professor at the University of Oklahoma, said in a statement.   

Boosting resilience at city-scale: A clearer estimate of future needs would also help people improve efficiency, develop and implement energy and environmental regulations, according to Wang, who heads the Sustainable Urban Futures Lab.  

• Such action, he explained, could enhance human resilience and adaptation capabilities amid extreme weather conditions.  
  
  
• “As global cities commit to ambitious sustainability goals, a more granular understanding of energy use at the city scale becomes imperative,” Wang added. 

The intersection of warming and power use: To gain such an understanding, Wang and colleagues from around the world focused on 277 cities across the contiguous U.S.

• They used model simulations and future climate projections to consider four possible warming scenarios and two power sector scenarios.
  
  
• One power scenario assumed not future carbon policies would be implemented. 
  
  
• The second involved rapid decarbonization and net-zero emissions transitions by 2050, in line with climate goals announced by President Biden earlier this year.   

Calculating consumption: Wang and his colleagues then used an indicator called energy use intensity (EUI), or the energy consumed per square foot per year, to determine how urban building energy use could evolve. 

They calculated the EUI by dividing the total energy used in the buildings by their total gross floor area, the authors explained.  

What did they find? The researchers observed that city-scale building EUI would undergo uneven changes by the 2050s, in comparison to baseline levels in the 2010s.  

The biggest increases would affect the South, Southwest, West and Southeast portions of the U.S., which would see a surge of up to 7.2 percent, according to the study. 

Peak usage could persist: The scientists also identified a likely rise in the frequency of summer peak electricity usage in urban buildings.  

• They found an average of 10.1 percent to 37.7 percent surge in such settings across the country.
  
  
• Some cities, however, may incur greater than 110-percent increases.  

“This will require higher grid capacity and also greater resilience against power outages during extreme heat waves,” Wang said.