New research from Stanford highlights the pivotal role of water systems, such as desalination plants and wastewater treatment facilities, in enhancing the affordability and reliability of renewable energy sources. The study introduces a comprehensive framework for assessing the capacity of water systems to adapt their energy consumption, thereby contributing to the equilibrium of power grid supply and demand.

“If we’re going to reach net zero, we need demand-side energy solutions, and water systems represent a largely untapped resource,” said study lead author Akshay Rao, an environmental engineering PhD 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 meet our decarbonization and water reliability goals.”

As the world increasingly shifts towards renewable energy sources such as wind and solar power, the challenge of balancing energy supply and demand becomes more pressing. While energy storage technologies like batteries are commonly used to address this issue, they can be quite costly.

However, an intriguing alternative has emerged: leveraging the demand-side flexibility of large-load consumers such as water conveyance and treatment providers. These water systems, which account for up to 5% of the nation’s electricity usage, have the potential to provide similar benefits to traditional batteries by adjusting their operations to align with real-time energy needs, as suggested by Rao and his co-authors.

To explore this promising concept further, the researchers have developed a comprehensive framework to assess the value of energy flexibility from water systems from both electric power grid operators’ and water system operators’ perspectives. This innovative framework compares the value of water systems’ energy flexibility with other grid-scale energy storage solutions, such as lithium-ion batteries.

It takes into account various factors, including reliability risks, compliance risks, and capital upgrade costs associated with delivering energy flexibility using critical infrastructure systems.

By examining the compelling potential of water systems to contribute to the balance of energy supply and demand, this research sheds light on a captivating opportunity for a more sustainable and cost-effective energy future.

Researchers put their method to the test across a seawater desalination plant, a water distribution system, and a wastewater treatment plant. They delved into the impact of varying tariff structures and electricity rates from utilities in California, Texas, Florida, and New York.

Their findings revealed that these systems have the potential to shift up to 30% of their energy consumption during peak demand periods, resulting in substantial cost savings and alleviating strain on the grid. Notably, desalination plants emerged as frontrunners in harnessing energy flexibility by adjusting water recovery levels or selectively halting operations during periods of high electricity prices.

The framework presents an opportunity for electricity grid operators to assess energy flexibility resources, compare them with other energy options, and adjust energy pricing. This approach also empowers water utility operators to make informed financial decisions in the face of evolving electricity grids.

The study emphasizes the crucial role of energy pricing in maximizing flexibility. Water systems that vary energy rates throughout the day stand to gain the most. Moreover, facilities could potentially generate additional revenue by reducing energy consumption during peak demand and participating in energy-saving programs offered by utilities.

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

Journal reference:

1. Akshay K. Rao, Jose Bolorinos, Erin Musabandesu, Fletcher T. Chapin & Meagan S. Mauter. Valuing energy flexibility from water systems. Nature Water, 2024; DOI: 10.1038/s44221-024-00316-4