Reviewed by Lexie CornerSep 30 2024
A recent study led by Stanford University shows how water systems, such as wastewater treatment plants and desalination plants, can enhance the affordability and reliability of renewable energy. The study presents a framework to quantify how these water systems can adjust their energy usage to help balance supply and demand on the power grid. The research was published in Nature Water.
As power grids increasingly rely on renewable energy sources like solar and wind, balancing energy supply and demand becomes more challenging. While batteries and energy storage technologies help in this regard, they can be expensive. An alternative approach is to encourage demand-side flexibility from large energy users, such as water transportation and treatment companies.
The study suggests that water systems could play a key role in improving grid stability while also generating new revenue streams.
If we’re going to reach net zero, we need demand-side energy solutions, and water systems represent a largely untapped resource. 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.
Akshay Rao, Study Lead Author and Ph.D. Student, Environmental Engineering, School of Engineering, Stanford University
According to Rao and his co-authors, water systems, which account for up to 5 % of the country's electricity consumption, could offer benefits similar to those of batteries if they adjust their operations in real-time to match energy demand.
A Framework for Flexibility
The researchers developed a framework to assess the potential of water systems for energy flexibility, evaluating it from the perspectives of both power grid operators and water system managers. This framework compares the energy flexibility benefits of water systems, such as wastewater treatment and desalination plants, to those of other energy storage technologies like lithium-ion batteries. It also considers factors such as reliability risks, regulatory compliance, and the costs of capital upgrades involved in using water systems for grid balancing.
To test their approach, the researchers analyzed three water systems: a wastewater treatment plant, a water distribution system, and a seawater desalination plant. They also explored the effects of various electricity pricing and tariff structures in states like Florida, Texas, California, and New York.
Their findings showed that these water systems could shift up to 30 % of their energy use during peak demand periods, resulting in significant cost savings and reduced grid strain. Desalination plants, in particular, demonstrated the highest potential for energy flexibility by adjusting water recovery or halting operations when electricity costs peak.
The researchers suggest the framework could help grid operators evaluate energy flexibility from different water systems and compare it with other energy storage options. It could also assist water utility operators in making better financial decisions about plant design and operations as electricity grids change.
The study emphasizes that energy pricing is key to maximizing this flexibility. Water systems that pay different rates for energy throughout the day could see the most benefit. Facilities might also earn extra revenue by using less energy during times of grid stress if utilities offer energy-saving programs.
Our study gives water and energy managers a tool to make smarter choices. With the right investments and policies, water systems can play a key role in making the transition to renewable energy smoother and more affordable.
Akshay Rao, Study Lead Author and Ph.D. Student, Environmental Engineering, School of Engineering, Stanford University
Journal Reference:
Rao, K. A., et al. (2024) Valuing energy flexibility from water systems. Nature Water. doi.org/10.1038/s44221-024-00316-4