In a reverse-osmosis system, brackish or salt water is pumped against one side of a special membrane. Fresh water passes slowly through the membrane, with the brinier water staying behind. A lot of electricity is required to pump the brackish or salt water into the system, maintain water pressure against the membranes, and, finally, pump the resulting fresh water to water towers to meet demand.
The key goal is keeping costs reasonable. “We do know you can bring [wind power and desalination] together, but can you bring down the cost of the system?” asks Minesh Shah, the project leader at GE Global Research, in Niskayuna, NY. “To be able to bring down capital, energy, and life-cycle costs, we need to be smarter in how we operate. It’s all about the energy-management system for these two integrated products. We look at it as energy sustainability and water sustainability.”
Any excess wind power could be sold to the power grid during peak times, when–in some regions–electricity fetches higher prices. “You would be making a real-time decision as to how the output of the wind turbine is going to be used: to deliver electricity to the grid, or to run the reverse-osmosis unit,” says Swift.