"I think people will swim or sail," Soffer said. "This being South Florida, we'll probably have people doing yoga on paddleboards."
Power companies will be a harder sell.
Most plants, whether they depend on coal, natural gas, or nuclear energy, produce electricity by making steam and using it to drive giant turbines. In the old days, plants were built near major bodies of water, which was then diverted through the plant, cooling the condenser and heating the water before dumping it back. These "once-through" systems are bad for aquatic life, says John Rogers, senior energy analyst at the Union of Concerned Scientists. That's one reason they gave way to "closed" cooling systems in the 1970s. Still, as of 2011, more than 30 percent of U.S. power plants used once-through systems.
Fischmann’s solution is to create such vast reservoirs that he can cool plants with water that passes by condensers in pipes, limiting evaporation. In 2014, a subsidiary of the Italian utility Enel tested Fischmann's technology to cool a power plant outside Santiago. The four-month experiment, funded by a Chilean economic development agency, proved that the "technology could be applied in any thermal plant," according to the power company. For his next trick, Fischmann wants to use the heat transferred to water via the cooling process to power a desalination plant.
Ultimately, the challenge is not only to create a better method for cooling, but to make it cost-effective to implement, said Eric Toone, a physical organic chemist who directs Duke University’s Innovation and Entrepreneurship Initiative. “That’s always the problem in energy (not will it work from a technical perspective—that’s easy): Can you do it on a gigawatt scale and still produce power for eight cents a kilowatt?”
Additional obstacles must be overcome. Fischmann claims his lagoons use less water than golf courses, but massive man-made lakes might not be the best use of a scarce resource. The current glut of U.S. golf courses, meanwhile, might serve as a cautionary tale: Twenty years ago, they were a must-have amenity for many U.S. homebuilders. Then the golf trend lost steam, leaving developers to let courses grow wild—or replace them with man-made lakes. It if a real estate developer can produce hundreds of miniature Caribbean Seas, it seems no less improbable that some of those crystalline bodies will one day run dry. At which point, Fischmann will have another problem to solve: What do you do with a giant hole in the ground?