Study shows how water systems can help accelerate renewable energy adoption

Research from Stanford reveals how water systems, from desalination plants to wastewater treatment facilities, could help make renewable energy more affordable and reliable. The study, published September 27 in Natural waterpresents a framework for measuring how water systems can adjust their energy use to help balance supply and demand from the electricity grid.

“If we want to get to net zero, we need demand-driven energy solutions, and water systems represent a largely untapped resource,” said the study’s lead author, Akshay Rao, a a doctorate in environmental engineering. student at the Stanford School of Engineering.

“Our method helps water operators and energy managers make better decisions about how to coordinate these infrastructure systems to simultaneously achieve our decarbonization and water reliability goals.”

As grids rely more on renewable energy sources like wind and solar, it becomes more difficult to balance energy supply and demand. Typically, energy storage technologies such as batteries help, but batteries are expensive. An alternative is to promote demand-side flexibility from large consumers such as water transport and treatment providers.

Water systems, which use up to 5% of the nation’s electricity, could offer similar benefits to batteries by adjusting their operations to align with real-time energy needs, according to Rao and his co-authors .

A framework of flexibility

To help realize this potential, researchers developed a framework that assesses the value of energy flexibility in water systems from the perspectives of power grid operators and water system operators.

The framework compares these values ​​to other grid-scale energy storage solutions, such as lithium-ion batteries that store electricity during periods of low energy demand and release it during peak periods. The framework also considers a range of factors, such as reliability risks, compliance risks and investment upgrade costs associated with providing energy flexibility using critical infrastructure systems.

The researchers tested their method on a seawater desalination plant, a water distribution system and a wastewater treatment plant. They also explored the effect of different rate structures and electricity rates from utilities in California, Texas, Florida and New York.

They found that these systems could reduce their energy consumption by up to 30% during periods of peak demand, leading to significant cost savings and easing pressure on the network. Desalination plants have shown the greatest potential for this type of energy flexibility by adjusting the amount of water they recover or shutting down certain operations when electricity prices are high.

The framework could help power grid operators evaluate energy flexibility resources across a range of water systems, compare them with other energy flexibility and energy storage options, and modify or price the energy, according to the researchers. This approach could also help water utility operators make more informed financial decisions about how they design and operate their plants at a time when electricity grids are rapidly evolving.

The study also highlights the importance of energy pricing to make the most of this flexibility. Water systems that pay different energy rates at different times of day could see the greatest benefits. Facilities could even earn extra money by reducing their energy use when the grid is stressed, as part of energy-saving programs offered by utilities.

“Our study gives water and energy managers a tool to make smarter choices,” Rao said. “With the right investments and policies, water systems can play a key role in making the transition to renewable energy smoother and more affordable.”

Meagan Mauter, associate professor in the Photon Science Directorate at SLAC National Accelerator Laboratory, is the lead author of this paper. She is also a principal investigator at the Stanford Woods Institute for the Environment and the Precourt Institute for Energy, and a pro bono associate professor of chemical engineering.