Some four miles off the Southern California coast, a company is betting it can solve one of desalination’s biggest problems by moving the technology deep below the ocean’s surface. OceanWell’s planned Water Farm 1 would use natural ocean pressure to power reverse osmosis — a process that forces seawater through membranes to filter out salt and impurities — and produce up to 60 million gallons (nearly 225 million liters) of freshwater daily. … OceanWell claims its deep sea approach — 1,300 feet (400 meters) below the water’s surface — would cut energy use by about 40% compared to conventional plants.