In 2021, a historic drought gripped California, forcing the state to cut back on power generation from hydro-electric power plants to help maintain the state’s water supply. To make up for the lost power, the state ramped up generation from natural gas plants that were slated for retirement.
“The electricity had to come from somewhere, and if the hydro plants fall off, then decision-makers are going to have to ramp up burning fossil fuels, which leads to more intense and frequent droughts and might make this situation more common,” said Renee Obringer, an assistant professor of energy and mineral engineering.
Obringer’s research focuses on addressing these kinds of complex interrelated issues surrounding the impact of climate change on water and energy systems.
That includes scientific questions about trade-offs associated with how we prioritize energy or water supply in the face of climate change, but also how those decisions impact people at the local level. Because while climate change is a global problem that will require solutions at national or international scales, the impacts are felt locally, she said.
“What I try to do in my research is take this global problem and narrow it down and look at what’s happening in different cities, at local levels, and focus more on adaptation,” Obringer said. “My thinking is if we talk more about these local impacts, we show people what they might experience, and what their neighbors might experience. And that may build some grassroots efforts to encourage those larger, national, and regional solutions to their local problems.”
Energy-Water Nexus
Water and energy systems are interconnected— power plants need water for cooling and electricity is required for water treatment and distribution in communities.
“When we need to generate more electricity, then we have this simultaneous impact on water,” Obringer said. “And if we need more water to be treated and distributed, we have a simultaneous impact on energy. My research looks at questions like if we increase our electricity needs, does that negatively impact our water supply during droughts, and if we are increasing air conditioning use during like a drought, how does that impact our water supply.”
Last year, Obringer and colleagues used utility data to model how climate change may impact residential water and electricity use across forty-six cities in the United States.
Their model projected strong regional differences for future water and electricity demand, with some cities possibly experiencing increases in summer water and electricity demand of up to 15 and 20 percent, respectively, because of climate change. The researchers published their findings, which could inform how cities learn from each other in planning for climate change mitigation, in the journal One Earth.
“We’re trying to understand how future climate change scenarios might impact water-electricity demand in U.S. cities,” Obringer said. “What do these changes actually show in terms of how our bulk demand is changing, and how do we bridge the gap between research data and practice to help management agencies plan resilience to future change and better serve residents?”
More recently, Obringer and a colleague published a dataset containing more than a decade of monthly water and electricity consumption data, from 2007 to 2018, for those forty-six cities in the journal Scientific Data.
While electricity consumption data is managed by the state and relatively easy to acquire, water data is often managed by localized water providers and may require traveling to individual cities to make copies of records. Obringer collected the data by filing requests under the Freedom of Information Act.
“We wanted to publish our dataset because acquiring this water consumption data is difficult,” she said. “We thought, ‘even if we only have forty-six cities, that’s better than what was available before, which was zero, because you have to go through each of these agencies individually.”
Obringer said the data can be used to evaluate the possible impacts of climate change on the water-electricity demand nexus by finding relationships between usage and climate.
“Using machine learning, we can take the known data—how much water a city used and what the weather was like—and find a mathematical relationship,” Obringer said. “We then substitute in future climate data and estimate how demand might change if precipitation drops or if temperatures rise.”
Increased demand, limited supply
The Colorado River Basin, which supplies water to forty million people in the Western United States, is threatened by historic drought, a changing climate and water demands from growing cities.
Because supply-based solutions like expanding reservoirs and providing more water are not an option, resource managers have increasingly focused on encouraging conservation behaviors in these areas.
“The Colorado River Basin is undergoing a nearly unprecedented level of drought— possibly the worst the region has experienced in 100 years,” Obringer said. “Recently, water managers have increasingly looked toward encouraging conservation behaviors, but the success of these strategies requires an understanding of community-specific attitudes and beliefs.”
Changing attitudes about water conservation could significantly impact water consumption and help address this issue, according to research Obringer and a colleague published this year the Journal of the American Water Resources Association.
The scientists used a machine learning technique called agent-based modeling to explore how households from various archetypes—like those who are willing to conserve water and those who prefer other solutions—will act under new conditions brought on by a changing climate.
This scenario testing revealed a statistically significant improvement to water availability after successfully changing water conservation attitudes to be more participatory, the researchers wrote in the paper. However, the work does not factor in potential decreases in water availability caused by climate change.
“We found that if we do work to change some of these attitudes, it can, in the long term, lead to more water availability in the future,” Obringer said.
Local impact, global solutions
Instead of explaining what two degrees Celius of global warming means, Obringer said her modeling approach can show households what they might experience under climate scenarios—like how much their electricity bill might increase.
“I hope people see what these impacts might be and then decide whether to make individual changes in their home or not,” she said.
While it is not practical to advise residents in certain parts of the county to avoid using air conditioning, if people understand impacts like potential increases in energy costs, they may be more willing to support the kinds of national or global policies that could address climate change, Obringer said.
“At the local level, we’re doing adaptation and we’re trying to build resilience,” Obringer said. “But if people start to see what these impacts are, they may raise their concerns up the ladder and tell the people who actually can make these larger mitigation choices that we need to do better.”