[ Above: David Ladner, an assistant professor of environmental engineering and earth sciences at Clemson, shows how water so dirty that it’s brown can be cleaned with a system of pumps and filters so that it’s drinkable. ]
About 40 Clemson University faculty members have joined the Water-Energy Consortium to find solutions to the future of energy. The consortium is studying the relationship between water and energy and developing sustainable solutions for the future.
Scott Husson and David Ladner are working on a hybrid-technology project focusing on the desalination of water and then harvesting the energy from that process.
“Everything is tied to water,” Husson said. “You can’t talk about water without talking about energy, and you can’t talk about energy without talking about water.”
Husson and Ladner are working with membranes that will allow water, but not salt, to pass through.
When a membrane is placed between pure water and salty water, Husson said, the pure water will naturally try to dilute the salty water.
The process, referred to as pressure-retarded osmosis (PRO), results in a buildup of pressure on the salt-water side, which will then turn a turbine.
The scientists are looking for ways to capture more energy than the process uses. Husson said the hard part is creating a membrane that is thin enough to be energy-efficient but also strong.
“Making them thin is problematic because they have to be strong enough to withstand that pressure,” he said.
Work on PRO has been around for many years, but the work is hampered because the process isn’t yet economically feasible, Husson said. But if the scientists develop a way to make the process energy-efficient, they could solve future energy problems.
Ladner said energy prices are relatively cheap right now, but could spike as natural resources become unavailable.
“Our water is dirt cheap, which is kind of ironic. We should call things ‘water cheap,’” he said.
He said water prices will go up, however, as available resources decrease. The work he and Husson are doing would help solve the dual problem of water scarcity and renewable energy production, he said.
Water scarcity is becoming much more relevant, Husson said, but the ocean offers a great solution if scientists can find an energy-efficient way to remove the salt from the water.
Ladner said the brine left over from the desalination is put back into the ocean. But if scientists can use the brine in a PRO application, the result could be a solution to finding a new sustainable energy source.
