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Desalination produces extremely concentrated brine as a waste product. Dumping that brine into coastal waters can kill a lot of marine life, so I imagine keepin

Desalination produces extremely concentrated brine as a waste product. Dumping that brine into coastal waters can kill a lot of marine life, so I imagine keeping the plant offshore helps. The current way the waste is handled is by laying a pipe from the shore deep underwater away from the coast. The brine is diluted with fresh seawater and pumped all the way down. By having the plant offshore, drawing in fresh water to dilute the waste becomes cheaper, and it's cheaper to build a vertical pipe to discharge the waste deep underwater. There's other byproducts like chlorine gas and sodium compounds released from cracking salt molecules. Small amounts, but keeping that offshore is a plus in my opinion.

ClumsyPilot 4y ago
why do you need desalination, you only need a small amount of fresh water for electrolysis. Any standard city water supply will power a very large electrolysis setup. Also you seem to be massively underestimating the effect of corrosion, and needing to transport stafff and eqipment back and forth offshore
- rolenthedeep 4y ago
  Tbh I got myself a bit mixed up. Desalination and hydrogen electrolysis have similar problems. Brine waste is still a problem with electrolysis. Everything that isn't water is left behind, and must be disposed of. Some of the dissolved gases and ions also get liberated, but in fairly small quantities. The article in question is about seawater electrolysis, and my understanding is that the dissolved ions in the water should improve efficiency (though I'm no expert). As far as corrosion, you're vastly overestimating the problem. We've been dealing with salt water corrosion for at least the last century. It isn't that bad if you keep up with maintenance. I used to work in the marine coatings industry, and the technology today is incredible. With a properly maintained coating and sacrificial anodes maintained regularly, corrosion damage is minimal. After all, we have countless steel cargo ships and oil rigs on the water today. A quick Google suggests that the lifespan of a cargo ship is on the order of 15-40 years. USS Olympia is a steel hull ship that's been in the water since 1945, and she seems to be doing fine. Salt water corrosion is a problem we know how to deal with, all it requires is regular maintenance. The cost of a good marine coating for something the size of an oil rig would be a couple hundred thousand dollars, and will last many years with regular maintenance. And as far as ferrying crew to the rig, the ferry from Seattle to Southworth costs about a million dollars a year, running 8 hours a day, ferrying up to 2400 people a day across 9 miles [0]. Extrapolate that to two or three round trips a day and you're down to a few hundred thousand dollars a year. Since the ferry is going to what is effectively a power station, it could even be powered electrically, which would further drive down the cost. Realistically, we've been building and manning offshore platforms for a very long time. Oil rigs don't rust out and collapse into the ocean. Cargo ships don't fall apart unexpectedly. We have a lot of steel floating in the ocean with no problems, as long as they are maintained. Yes, there are problems building structures in hostile environments. But we've been doing it for a very long time, and most of these problems have solutions. [0] https://leg.wa.gov/JTC/Documents/POFCostAnalysis.pdf https://leg.wa.gov/JTC/Documents/POFCostAnalysis.pdf

ClumsyPilot 4y ago

why do you need desalination, you only need a small amount of fresh water for electrolysis. Any standard city water supply will power a very large electrolysis setup. Also you seem to be massively underestimating the effect of corrosion, and needing to transport stafff and eqipment back and forth offshore

rolenthedeep 4y ago
Tbh I got myself a bit mixed up. Desalination and hydrogen electrolysis have similar problems. Brine waste is still a problem with electrolysis. Everything that isn't water is left behind, and must be disposed of. Some of the dissolved gases and ions also get liberated, but in fairly small quantities. The article in question is about seawater electrolysis, and my understanding is that the dissolved ions in the water should improve efficiency (though I'm no expert). As far as corrosion, you're vastly overestimating the problem. We've been dealing with salt water corrosion for at least the last century. It isn't that bad if you keep up with maintenance. I used to work in the marine coatings industry, and the technology today is incredible. With a properly maintained coating and sacrificial anodes maintained regularly, corrosion damage is minimal. After all, we have countless steel cargo ships and oil rigs on the water today. A quick Google suggests that the lifespan of a cargo ship is on the order of 15-40 years. USS Olympia is a steel hull ship that's been in the water since 1945, and she seems to be doing fine. Salt water corrosion is a problem we know how to deal with, all it requires is regular maintenance. The cost of a good marine coating for something the size of an oil rig would be a couple hundred thousand dollars, and will last many years with regular maintenance. And as far as ferrying crew to the rig, the ferry from Seattle to Southworth costs about a million dollars a year, running 8 hours a day, ferrying up to 2400 people a day across 9 miles [0]. Extrapolate that to two or three round trips a day and you're down to a few hundred thousand dollars a year. Since the ferry is going to what is effectively a power station, it could even be powered electrically, which would further drive down the cost. Realistically, we've been building and manning offshore platforms for a very long time. Oil rigs don't rust out and collapse into the ocean. Cargo ships don't fall apart unexpectedly. We have a lot of steel floating in the ocean with no problems, as long as they are maintained. Yes, there are problems building structures in hostile environments. But we've been doing it for a very long time, and most of these problems have solutions. [0] https://leg.wa.gov/JTC/Documents/POFCostAnalysis.pdf https://leg.wa.gov/JTC/Documents/POFCostAnalysis.pdf