5 ms·

There is no fresh watter at sea wind generator fields.

by _0w8t 4y ago

tinco 4y ago
Nice, that's a cool scenario I hadn't thought of. I haven't heard of any deep sea wind generators, but obviously that might have great yields. I wonder if that far out at sea it wouldn't be easier/more feasible to have solar panels instead of wind mills.
- deleted 4y ago
  [deleted]
- deepnet 4y ago
  Tidal turbines are a good contender. The tides are constant.
  - onphonenow 4y ago
    As someone who has spent a fair bit of time in / around salt water I’m skeptical of these claims. I want to see all in deployment costs with maintenance. Are these deep water or do they need to be shallow water where they will be banged up even more in storms etc
    - dncornholio 4y ago
      I don't know about tidal forces, I do know in the Netherlands they create energy from salt / fresh water dialysis. https://redstack.nl/en/ https://redstack.nl/en/
  - jcampbell1 4y ago
    Tidal turbines are viable in inlets where currents are consistently strong during tidal changes, the problem is they often disrupt the ecosystems around where fish need to spawn. Altering the total water flow into estuaries is sketchy and the good places are typically shipping lanes. You could put them in a place like Gibraltar and live with reduced water exchange in the Mediterranean, but it will be met with a lot of resistance. Ideas that rely on moving a mass up and down 10 feet every 6 hours require floating platforms the size of Rhode Island. Not cheap to build. Neither strategy is a contender in my book. I recall a research project in France which the results were unappealing. The environmental costs were high and power generated was low. You have to be careful getting scientific knowledge from the mainstream press or researchers who need to sell their research which means it is more akin to marketing than scientific knowledge.
    - moloch-hai 4y ago
      Attempts at tidal power extraction in the Bay of Fundy have failed because the turbines broke, every time. Attaching a simple float to a cable and pulley turning a generator onshore seems not to have occurred to them. Numerous (i.e. all) wave energy startups have likewise gone bust trying to keep machinery working exposed to maritime weather. It seems never to occur to them to keep the stuff that would need attention onshore and indoors.
- chr1 4y ago
  Using [1] temperature difference between deep water and surface water may be even more efficient [1] https://en.m.wikipedia.org/wiki/Ocean_thermal_energy_conversion https://en.m.wikipedia.org/wiki/Ocean_thermal_energy_convers...
  - moloch-hai 4y ago
    You can bypass the heat engine, and just condense humidity onto coils with cold deep water running through them. You only need an insulated pipe to bring the deep water up through. The more water you move, the less insulation you need.
- semi-extrinsic 4y ago
  Offshore wind is proven tech at this point, to the point that there are commercial offshore wind farms that have been built without any subsidies. Mainly in Europe but starting also in the US. There is no major R&D necessary to make it happen, just scaling and cost engineering. The Biden administration target for 2030 is to have 30 GW installed generation capacity in offshore wind.
  - tinco 4y ago
    Yeah but none so far away that you couldn't just lay a cable to transmit the power to the shore.
  - jcampbell1 4y ago
    > Offshore wind is proven tech at this point Shallow water only. The North Sea is perfect, the east coast of the US looks good in places. Deep water is unproven currently and in the R&D stage with no known economically viable solutions.
    - moloch-hai 4y ago
      Major construction projects are ongoing, based on already proven solutions.
      - canadianfella 4y ago
      - jcampbell1 4y ago
        Bullshit. Best so far is Hywind, which is 3x the cost per MWh of shallow offshore.
- MisterTea 4y ago
  There is also https://en.wikipedia.org/wiki/Wave_power https://en.wikipedia.org/wiki/Wave_power
ClumsyPilot 4y ago
Its easier to lay an electric cable to shore than to build a hydrogen plant at the sea, deal with corrosion, move hubdreds of staff there every day by boat and canisters of pressurised hydrogen. I am not seeing the practicality of this outside of some really niche areas.
- rolenthedeep 4y ago
  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

There is no fresh watter at sea wind generator fields.

by _0w8t 4y ago

There is no fresh watter at sea wind generator fields.

Nice, that's a cool scenario I hadn't thought of. I haven't heard of any deep sea wind generators, but obviously that might have great yields. I wonder if that far out at sea it wouldn't be easier/more feasible to have solar panels instead of wind mills.

deleted 4y ago
[deleted]
deepnet 4y ago
Tidal turbines are a good contender. The tides are constant.
- onphonenow 4y ago
  As someone who has spent a fair bit of time in / around salt water I’m skeptical of these claims. I want to see all in deployment costs with maintenance. Are these deep water or do they need to be shallow water where they will be banged up even more in storms etc
  - dncornholio 4y ago
    I don't know about tidal forces, I do know in the Netherlands they create energy from salt / fresh water dialysis. https://redstack.nl/en/ https://redstack.nl/en/
- jcampbell1 4y ago
  Tidal turbines are viable in inlets where currents are consistently strong during tidal changes, the problem is they often disrupt the ecosystems around where fish need to spawn. Altering the total water flow into estuaries is sketchy and the good places are typically shipping lanes. You could put them in a place like Gibraltar and live with reduced water exchange in the Mediterranean, but it will be met with a lot of resistance. Ideas that rely on moving a mass up and down 10 feet every 6 hours require floating platforms the size of Rhode Island. Not cheap to build. Neither strategy is a contender in my book. I recall a research project in France which the results were unappealing. The environmental costs were high and power generated was low. You have to be careful getting scientific knowledge from the mainstream press or researchers who need to sell their research which means it is more akin to marketing than scientific knowledge.
  - moloch-hai 4y ago
    Attempts at tidal power extraction in the Bay of Fundy have failed because the turbines broke, every time. Attaching a simple float to a cable and pulley turning a generator onshore seems not to have occurred to them. Numerous (i.e. all) wave energy startups have likewise gone bust trying to keep machinery working exposed to maritime weather. It seems never to occur to them to keep the stuff that would need attention onshore and indoors.
chr1 4y ago
Using [1] temperature difference between deep water and surface water may be even more efficient [1] https://en.m.wikipedia.org/wiki/Ocean_thermal_energy_conversion https://en.m.wikipedia.org/wiki/Ocean_thermal_energy_convers...
- moloch-hai 4y ago
  You can bypass the heat engine, and just condense humidity onto coils with cold deep water running through them. You only need an insulated pipe to bring the deep water up through. The more water you move, the less insulation you need.
semi-extrinsic 4y ago
Offshore wind is proven tech at this point, to the point that there are commercial offshore wind farms that have been built without any subsidies. Mainly in Europe but starting also in the US. There is no major R&D necessary to make it happen, just scaling and cost engineering. The Biden administration target for 2030 is to have 30 GW installed generation capacity in offshore wind.
- tinco 4y ago
  Yeah but none so far away that you couldn't just lay a cable to transmit the power to the shore.
- jcampbell1 4y ago
  > Offshore wind is proven tech at this point Shallow water only. The North Sea is perfect, the east coast of the US looks good in places. Deep water is unproven currently and in the R&D stage with no known economically viable solutions.
  - moloch-hai 4y ago
    Major construction projects are ongoing, based on already proven solutions.
    - canadianfella 4y ago
    - jcampbell1 4y ago
      Bullshit. Best so far is Hywind, which is 3x the cost per MWh of shallow offshore.
MisterTea 4y ago
There is also https://en.wikipedia.org/wiki/Wave_power https://en.wikipedia.org/wiki/Wave_power

ClumsyPilot 4y ago

Its easier to lay an electric cable to shore than to build a hydrogen plant at the sea, deal with corrosion, move hubdreds of staff there every day by boat and canisters of pressurised hydrogen. I am not seeing the practicality of this outside of some really niche areas.

rolenthedeep 4y ago
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