In this article, you'll learn:
- How energy and water systems depend on each other, often in a fragile balance
- The impact of drought, heatwaves, and rising electricity demand on both systems
- How researchers use AI and data modeling to help utilities plan for a more resilient future
Every time you turn on a light or fill a glass of water, you’re tapping into one of the world’s most important — and least understood — connections: the water-energy nexus. Producing electricity requires vast amounts of water, while cleaning and delivering water depend on energy. As droughts, population growth, and new technologies reshape both systems, understanding this relationship is essential for a sustainable future.
In this Q&A, Renee Obringer, assistant professor in Penn State’s Department of Energy and Mineral Engineering, discusses how water and energy depend on each other, what happens when that balance is disrupted, and how her research helps communities plan for resilience in a changing climate.
How are water and energy connected?
When I talk about water and energy, I usually start with the supply side. Generating electricity — whether it’s through hydropower, fossil fuels, or nuclear — requires water. Hydropower, of course, depends on moving water to create electricity. Thermoelectric power plants — those that use heat from coal, gas, or nuclear sources — need vast amounts of water for cooling.
On the flip side, treating and distributing water also uses a lot of electricity. Utilities use energy to pump, treat, and deliver clean water, creating a feedback loop: more water demand raises power demand, and more power generation pulls more water from the system.
There’s also a demand-side connection. Everyday activities like washing clothes or heating water use both electricity and water. So, when we use more water at home, we indirectly use more energy — and vice versa. People often recognize the "water for energy” connection, but overlook how much electricity is embedded in getting clean water to our taps. Water treatment plants run 24/7 and are some of the largest electricity users in most cities.
How does energy production affect water quantity and availability?
It depends on the energy source. Thermoelectric plants that use coal, natural gas, or nuclear power rely heavily on water for cooling. While much of that water is returned to the system, it’s often warmer, which affects aquatic ecosystems and recreation — especially when the plant draws from a reservoir. During droughts and heatwaves, the problem worsens because warmer water cools less efficiently, reducing a plant’s power generation capacity.
Hydropower has its own challenges. Reservoirs that serve both hydropower and drinking water can face competing demands during droughts — hydropower requires steady water flow to move the turbines, while cities want to store water for human use.
In 2021, California’s Lake Oroville dropped so low that authorities shut off its hydropower plant to preserve emergency storage. The shutdown forced the state to rely on older, higher-emission natural gas plants, undercutting clean-energy goals. It’s a vivid example of how failing to plan for water-energy interactions can backfire.
How does water availability influence energy reliability?
They’re completely interconnected. When water is scarce or unusually warm, it restricts how much electricity we can generate — particularly from hydropower and thermoelectric plants. Reduced water availability can shut down hydropower altogether, as happened in California, or reduce cooling efficiency in fossil fuel and nuclear facilities.
Just as energy systems impact water quantity and quality, water conditions directly shape energy reliability. For example, power plants may need to reduce output if releasing warm water would exceed temperature limits designed to protect fish and aquatic life.
What does a sustainable energy future look like when water is part of the picture?
I think water is often left out when we talk about clean energy. The focus tends to be on wind, solar, or nuclear — sources that seem water-light compared to coal or gas. But water still matters deeply, even in a renewables-based future.
For example, data centers are expected to be a major source of electricity demand in Pennsylvania. They not only use large amounts of power but also require water for cooling. And while Pennsylvania produces more electricity than it consumes, that surplus goes to other states — it’s not “extra” for us to waste.
A sustainable energy future must consider not just how we generate electricity but how much we consume. Every kilowatt-hour carries an embedded water cost. If our electricity demand keeps rising — through data centers, electric vehicles, or high-tech infrastructure — we risk stressing our water systems, even in regions that haven’t historically faced scarcity. The 2024 Mid-Atlantic drought showed how quickly conditions can change.
How does your research help guide more sustainable water-energy decisions?
A lot of my early work examined residential water and electricity demand. I was inspired by a study from Phoenix, where homes that replaced lawns with desert landscaping used much less water, but their electricity use went up. The reason was microclimate: grassy areas slightly cool neighborhoods, so removing them raised local temperatures, forcing residents to run air conditioning more. That tradeoff showed how saving water can unintentionally increase energy use, and vice versa.
Since then, my research has looked more broadly at how climate change affects both water and energy demand, and how these systems can be managed together instead of separately. Many utilities—like those I worked with in Indianapolis — operate in silos. The water utility and the electric utility often don’t communicate, even though their systems depend on each other.
My current work examines these tradeoffs in integrated systems: for instance, how reservoir management affects hydropower reliability versus drinking water security. I use machine learning and AI modeling to project outcomes under different climate scenarios. These tools help communities and utilities make science-based plans that build resilience across both systems.
California is a major focus because of its drought cycles, data availability, and energy diversity. But my research spans dozens of U.S. cities, offering insights to help local agencies make proactive, informed decisions instead of reacting to crises.
It’s important to remember that while climate change and the water-energy nexus are national and global issues, the impacts are felt locally. Climate change affects every region differently. By building models and tools that translate large-scale dynamics into community-level insights, we can ensure that resilience planning actually works for the people and places most affected.
Renee Obringer is an assistant professor with the Department of Energy and Mineral Engineering, where her research focuses on leveraging data science methods to better understand the impact of weather and climate on critical infrastructure systems. She is particularly interested in studying climate change impacts on interdependent infrastructure systems (e.g., the water-energy nexus).
