AUSTIN — Texas lawmakers are poised to clear regulatory obstacles to building Gulf of Mexico desalination plants, but experts say turning on the tap for a thirsty state will come at a cost.
“The energy cost is high, but it’s not grotesque,” said Mark Holtzapple, a Texas A&M University chemistry professor, referring to reverse osmosis, the method used to convert sea water into water people can drink. “Any part of the world that’s experiencing water problems should use desalination as part of a portfolio of solutions.”
As things stand, private entities will not pay for the planning of desalination projects, or invest in large-scale sea water desalination projects without legal and regulatory clarification.
A Senate bill now in committee would remove legal barriers and enable Texas regulators to develop regional approaches for large-scale sea water desalination — and eventually make way for construction.
In Florida, residents have been drinking tap water from Tampa Bay since 2007.
“I would say it’s a success story. It’s a very reliable source,” said Ken Herd, a construction and contract section leader with Tampa Bay Water, which supplies desalinated drinking water to about 2.3 million customers in cities such as St. Petersburg and Tampa. “I hear more positive than negative.”
The bad news is, the project, which was then the biggest in the Western Hemisphere, came in four years late and $48 million over budget after the original builder went bankrupt.
And, Herd said, desalinated water costs customers about five times more than surface water, not counting debt service on the $158 million project.
Richard M. Crooks, a University of Texas at Austin chemistry professor, noted that customers have to pay for the energy it takes to convert salt water into tap water.
“It’s pretty energy intensive. The question is, just how much do you need the water,” Crooks said. “I think it’s responsible if people need water.
“There’s nothing more important. If you run out of water, the party is over.”
Crooks said that California, like Florida, hasn’t had a problem-free experience with desalination.
The state built a desalination plant in Santa Barbara 20 years ago, then had the wettest March ever.
“The plant was never turned on,” Crooks said, though now it’s being ramped up. “They’re scrambling around looking for floppy-disc drives.”
Apart from cost overruns and weather fluctuations, there’s the problem of dispersing the highly saline outflow — after processing it’s much saltier than the surrounding ocean water, and can kill sea life — and the fact that you pay potential pollution cost: burning coal to power a plant that runs desalination plants, for instance.
Holtzapple acknowledged the drawbacks.
“The only reason you build a desalination plant is, you don’t have free water falling out of the sky. To be honest, desalination is probably the last line of defense,” Holtzapple said. “But you can make as much as you want. It’s always there when you need it. There’s an infinite supply.”
It’s practiced all over the world — particularly in the Middle East, said Holtzapple, who is working on ways to lower the cost of desalinating water.
“It’s an evolving field. It’s not stagnant,” he said.
Meanwhile, given Texas’ ongoing drought, Crooks said Texas lawmakers could indeed get serious about desalination this session.
“The government doesn’t do anything until there’s a crisis,” Crooks said. “When they turn on their tap and nothing comes out, then something will happen.”