A University of Oklahoma study predicts significant changes in urban building energy consumption due to climate change, highlighting the need for strong mitigation strategies and energy efficiency improvements. The researchers found that for each degree of average climate warming, the energy required to cool buildings in U.S. cities is likely to increase by 13.8%.
A study led by Chenghao Wang, assistant professor at the University of Oklahoma, recently published in the journal Nature Communications, explores the critical question of how city-scale building energy consumption in urban environments will evolve under the influence of climate change.
Fossil fuels account for approximately 40% of all building energy use in U.S. urban centers, and the U.S. Energy Information Administration reports that residential and commercial buildings in U.S. cities are among the major energy consumers (39%) and greenhouse gas emitters (28%). Understanding cities' future energy use is important for developing climate change mitigation strategies, improving energy efficiency, developing and implementing energy and environmental regulations, policies and incentive programs, and increasing the resilience and adaptability of our societies to future climates and extreme weather conditions.
Previous research and current research objectives
"Previous research has made great strides in estimating how energy use at the national or state level will respond to future climate change," he said. "However, there are still large gaps in our understanding at the urban scale. As cities around the world work toward ambitious sustainability goals, a more granular understanding of energy use at the city scale is imperative."
Members of the research team include Janet Reyna and Henry Horsey from the National Renewable Energy Laboratory, Song Jiyun, Shi Dachuan and Zhou Yu from the University of Hong Kong, Sarah Feron from the University of Santiago in Chile, Ouyang Zutao and Robert Jackson from Stanford University, and Li Ying from China Three Gorges University.
They studied 277 cities in the contiguous United States using model simulations and the latest future climate projections from the Coupled Model Intercomparison Project (CMIP6) dataset. They considered four possible climate warming scenarios, including a variety of possible climate warming scenarios and two power sector scenarios.
"In one power sector scenario, we assume that no carbon policies will be implemented in the future, but we also include a scenario that assumes the power sector will rapidly decarbonize and achieve net-zero carbon emissions by 2050, similar to the carbon pollution-free goal announced by U.S. President Biden in 2023," Wang Chenghao said.
Research findings and implications
To study the evolution of urban building energy use under future climate change, Wang Chenghao's team used a metric called energy use intensity (EUI). EUI is energy consumption per square foot per year and is calculated by dividing the total energy consumed by the building by the total floor area.
"Due to climate change, we find that city-scale building EUI is expected to change unevenly by the 2050s compared to the 2010s, with the largest increases in electricity EUI occurring primarily in the South, Southwest, West and Southeast, with increases of up to 7.2%."
They found that during the warm season and hottest days, the increase in electricity EUI will be much greater than the year-round change, especially in the northwest. The main reason for this difference is that air conditioning adoption and energy use for space cooling will be higher in a warmer future. For each degree of warming, average space cooling EUI at the city level will increase by 13.8%.
"We found that urban summer peak building electricity consumption EUI increased by 10.1% to 37.7% on average. However, the increase in some cities will exceed 110%. This will require higher grid capacity and stronger ability to withstand extreme heat wave blackouts," Wang said.
The team also assessed potential changes in the sources of energy used by urban buildings, taking into account energy losses during power generation, transmission and distribution.
"Decarbonization of the power sector is very effective in curbing source energy consumption in future urban buildings, but the key is to further reduce the direct combustion of fossil fuels in buildings," Wang said. "Simply put, we need to quickly electrify the urban buildings of the future."