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What are the upsides/downsides of water currents vs air currents here? Is one more consistent than the other? I imagine that water has more chunks to filter.

What are the upsides/downsides of water currents vs air currents here? Is one more consistent than the other? I imagine that water has more chunks to filter. Water requires a smaller turbine. ..?

samwillis 4y ago
Predictability, with tidal power you know exactly (more or less) how much you will generate every moment of every day.
Qworg 4y ago
Water carries (IIRC) ~375x the energy of air per speed/unit volume. Depending on the turbine design, you don't need to filter anything. The currents (gyre power) are far more consistent than wind turbines. If not for the difficulties of siting, permitting, and maintaining subsea equipment, gyre power systems are far superior.
zwayhowder 4y ago
I've seen companies use wave energy before (1) but not ocean currents, but as someone else pointed out, the currents are a lot more powerful and consistent than winds so it makes sense. I know Carnegie (2) talk up the fact that submerged equipment very rarely gets damaged by storms etc compared to floating or land based systems. (As long as they can keep fishing trawlers away and ban boat anchors in the area.). 1: https://www.offshore-energy.biz/carnegie-preps-new-ceto-design-for-june-wave-tank-tests/ https://www.offshore-energy.biz/carnegie-preps-new-ceto-desi... 2: https://www.carnegiece.com/ https://www.carnegiece.com/
bobthepanda 4y ago
Water is stronger than air. This is a double edged sword; IIRC most tidal power projects have failed because the greater wear and tear is worse than the additional power generated. I would imagine the deep ocean magnifies this problem. Not to mention, we do enough environmental damage to our oceans as it is.
Gwypaas 4y ago
Another company in a similar space, although focused on tidal currents is Minesto. The problem with wind vs. water is the extreme harshness of the environment. The only industry which has truly manage to tame the ocean is the oil and gas industry, and that at huge costs offset by the high value of what they produce. Not likely we will ever see anything like that in the renewable field. No affiliation but an old colleague works there so see them pop up from time to time https://minesto.com/ https://minesto.com/
- belorn 4y ago
  Salt, water, very strong forces, and a lot of things want to stick to it and build up layers of sand and organic material. And getting trained professionals that can operate in that environment is costly, slow and dangerous. Beyond those, are there any additional problems from the environment?
  - Gwypaas 4y ago
    The places with strong tidal currents have a tendency of limiting construction to ebb and high tide, in other words lot of expensive waiting around. Regarding the environment, under the sea it is quite fine compared to stationary platforms operating in the north sea or Mexican gulf(hurricanes) year around, so that should be easier.
- olejorgenb 4y ago
  Another: https://simecatlantis.com/tidal-stream/ https://simecatlantis.com/tidal-stream/
bayesian_horse 4y ago
Having the turbines submerged means stuff builds up on top of them. Eventually the blades have to be scrubbed or replaced. Maintenance would be simpler than for offshore wind turbines, I guess. You just need to pull them up, instead of climbing up a pole. Maybe you don't even need to service them at high sea but just carry them to shore.

What are the upsides/downsides of water currents vs air currents here? Is one more consistent than the other? I imagine that water has more chunks to filter. Water requires a smaller turbine. ..?

samwillis 4y ago

Predictability, with tidal power you know exactly (more or less) how much you will generate every moment of every day.

Qworg 4y ago

Water carries (IIRC) ~375x the energy of air per speed/unit volume. Depending on the turbine design, you don't need to filter anything. The currents (gyre power) are far more consistent than wind turbines. If not for the difficulties of siting, permitting, and maintaining subsea equipment, gyre power systems are far superior.

zwayhowder 4y ago

I've seen companies use wave energy before (1) but not ocean currents, but as someone else pointed out, the currents are a lot more powerful and consistent than winds so it makes sense. I know Carnegie (2) talk up the fact that submerged equipment very rarely gets damaged by storms etc compared to floating or land based systems. (As long as they can keep fishing trawlers away and ban boat anchors in the area.). 1: https://www.offshore-energy.biz/carnegie-preps-new-ceto-design-for-june-wave-tank-tests/ https://www.offshore-energy.biz/carnegie-preps-new-ceto-desi... 2: https://www.carnegiece.com/ https://www.carnegiece.com/

bobthepanda 4y ago

Water is stronger than air. This is a double edged sword; IIRC most tidal power projects have failed because the greater wear and tear is worse than the additional power generated. I would imagine the deep ocean magnifies this problem. Not to mention, we do enough environmental damage to our oceans as it is.

Gwypaas 4y ago

Another company in a similar space, although focused on tidal currents is Minesto. The problem with wind vs. water is the extreme harshness of the environment. The only industry which has truly manage to tame the ocean is the oil and gas industry, and that at huge costs offset by the high value of what they produce. Not likely we will ever see anything like that in the renewable field. No affiliation but an old colleague works there so see them pop up from time to time https://minesto.com/ https://minesto.com/

belorn 4y ago
Salt, water, very strong forces, and a lot of things want to stick to it and build up layers of sand and organic material. And getting trained professionals that can operate in that environment is costly, slow and dangerous. Beyond those, are there any additional problems from the environment?
- Gwypaas 4y ago
  The places with strong tidal currents have a tendency of limiting construction to ebb and high tide, in other words lot of expensive waiting around. Regarding the environment, under the sea it is quite fine compared to stationary platforms operating in the north sea or Mexican gulf(hurricanes) year around, so that should be easier.
olejorgenb 4y ago
Another: https://simecatlantis.com/tidal-stream/ https://simecatlantis.com/tidal-stream/

bayesian_horse 4y ago

Having the turbines submerged means stuff builds up on top of them. Eventually the blades have to be scrubbed or replaced. Maintenance would be simpler than for offshore wind turbines, I guess. You just need to pull them up, instead of climbing up a pole. Maybe you don't even need to service them at high sea but just carry them to shore.