Posted by: Burt Hamner

Campaign: How can you make drinkable water from the ocean?

Fresh water is often made from ocean salt water using Reverse Osmosis (RO). This requires significant pressure to push water molecules through a membrane filter. Waves in the ocean have enough energy to drive large hydraulic systems capable of generating the pressure needed for RO. A vertical-motion wave energy generator is now under construction in the Seattle region. This device can be installed inside a 200-ft ocean-going barge. The barge will be towed to the Washington outer coast, which has very high wave energy. There the barge will be anchored. As the waves move it up and down the wave energy harvester will move up and down like a pendulum and drive hydraulic pumps full of seawater through RO systems. The resulting brine waste will be dumped back in the sea and the fresh water will be discharged into the barge hull. When it is full the barge will be towed to shore and the fresh water pumped out. The barges can be towed in a chain. A typical 15-barge chain can transport 22,500 tons of fresh water. Except for the new wave-powered pump, all the equipment and technology for this idea is on the market and ready to use. The wave-powered pump is under construction and will be finished this year. Several commercial Port Authorities have already signed up to use this technology.