Hydropower

Cornell engineers refine model for pumped storage, seawater desalination

Cornell engineers refine model for pumped storage, seawater desalination

Engineers with Cornell University have refined a model that includes green energy production and desalination of ocean water for drought-stricken coastal populations.

“With our growing population, there are increasing energy demands and mounting freshwater needs,” said Maha Haji, assistant professor in the Sibley School of Mechanical and Aerospace Engineering.

By pumping seawater to a mountaintop reservoir and then using gravity to send the salty water to a co-located hydropower plant and a reverse osmosis desalination facility, science can satisfy the energy and hydration needs of coastal cities with one system, according to a release. After the ocean water is pumped using renewable electricity and runs through to the hydropower plant and community-scale desalination system, the concentrated leftover brine would meet up and become diluted with the fallen ocean water and conveyed back out to sea.

Haji and Matthew Haefner, a doctoral student in systems engineering, are co-authors of “Integrated Pumped Hydro Reverse Osmosis System Optimization Featuring Surrogate Model Development in Reverse Osmosis Modeling,” which was published in Applied Energy.

The Integrated Pumped Hydro Reverse Osmosis System (IPHROS) is a two-system model that combines energy storage and freshwater production in a symbiotic way, Haji said. “The reservoir storage will allow coastal communities to tap into renewable energy for their electric grid and potable water production. The reverse osmosis portion of this model adds flexibility to the system.”

With optimal model designs, a large system can supply 79.5 million kWh of electricity and 5.79 million cubic meters of fresh water per day, according to the researchers.

The IPHRO system can help reduce capital investment in building costs, lower maintenance overhead and bring about a natural way to dilute the highly saline discharge following reverse osmosis, Haefner said.

The paper credits Alexander Slocum, a professor of mechanical engineering at the Massachusetts Institute of Technology, for introducing the IPHROS concept in 2016. Haji was a co-author on that work. This research extends the concept by offering detailed mathematical modeling, as well as presenting a framework for optimizing the design and operation to maximize freshwater and energy production, according to Cornell University.

Cornell provided funds for this research.

Originally published in Hydro Review.