To remind, the MeyGen project’s Phase 1A involved the installation of the AR1500 onto a gravity-based foundation, alongside three other AH1000 MK1 turbines, to form an array of 6MW.
From what I've found, the AR1500 has just had routine quarter-life maintenance[2], but I can't find anything concrete right now which of the four made the 6 year milestone. I do note that in the brochure[3] for the AR1500 they claim three service intervals every 6 1/4 years, rather than four service intervals as indicated by the article.
GPs link doesn't even show what was claimed ("The other 3 have needed costly maintenance").
From that link:
"The first of these turbines is scheduled for redeployment in May 2022, with the final turbine to be deployed in March 2023, complete with a retrofitted wet mate connection system, which more than halves the costs of future turbine recoveries and deployments."
"The company’s AR150 turbine was re-deployed last month, after being out of the water for upgrade and maintenance work."
The single long-running turbine can be compared to the upgraded turbines to measure the effect of the upgrades, and it provides the headlines this thread is about. The upgrades themselves are also clearly valuable R&D work.
Also there is theoretically power in the GW range to be harvested here (specifically, Scotland’s tidal flows), so it’s worth investing a substantial sum to figure this tech out.
I'm not a turbine, or power generation, expert but I am almost 100% sure that no non-solar power generation method can operate without being taken down periodically for maintenance.
How do the maintenance costs (and intervals) of these compare to gas/steam turbines?
I assume corrosion is to blame? Crazy how much ocean facing stuff is still done with painted steel. You'd think aluminum and carbon fiber or even plastic would be making strides but it's still the iron age in many ways it seems.
Carbon fibres themselves may be corrosion resistent, but the fibers by themselves are like a fabric. If you want a solid part instead of cloth, you need to encase the fibers in a resin. Imagine it like a piece of cloth soaked in beeswax or candle wax: it is solid like the resin but if you pull on it, it has the strength of the fibers of the cloth.
The resins used for carbon fibers are usually very bad at contact with water over long periods of time. Even those in aerospace applications require coating/paint if exposed moisture over time. It’s a plastic, even the best ones don’t do so well in water after a few months.
Furthermore, the damage that moisture does to the resin can be difficult to detect and even more difficult if not impossible to fix. It requires clean rooms, skilled labor and machinery that you don’t have in the middle of an ocean.
Then take iron corrosion: it is easy to spot by naked eye, it may not be easy to repair, but it is relatively simple to “halt” further damage by removing the rust and adding new paint.
Don’t get me wrong: carbon fibers are amazing, but sometimes the “boring” solution is best.
PS: steel alloys and coatings can be amazingly high tech too, it’s amazing what can be engineered.
All industrial generators undergo regular shutdowns for maintenance and recalibration. This is costly and time consuming when they are on land.
Also, I am thinking about all the ocean factors beyond salt corrosion. There's tons of crap in the water beyond salt and minerals. Like fine grit suspended in it. Plus the tidal forces etc.
Steel has the benefit of fatigue limit. Which means as long as the cyclic stress on steel is under a certain amount it won't fail. Aluminium has a much lower fatigue strength than steel and will always fail given enough cycles.
While rust can be a problem it can be mitigated. Also steel is easier to repair than many other materials (welding).
BTW. Aluminium does suffer from corrosion as well. I used to have racing bike, the wheel nipples (these connect the spokes to the wheel rim) used to corrode to the point where they would fail, which meant I would end up with a buckle. I ended up having both wheel rebuilt with higher quality brass nipples.
Plastics under time also suffers from a different set of issues. Plastics can become brittle. Anyone working on old computers (especially macs) can attest to this.
Corrosion, the force of water (being 800 times as dense as air and effectively incompressible, water forces can be huge), objects in the water (again, water being heavy it can move heavy objects around in its flow), fouling through, for example, algae and mussels (https://en.wikipedia.org/wiki/Fouling)
Over many years, I've yet to hear of an ocean based power generating system that comes anywhere near the $ per kWh cost produced by just covering some less-useful land in ground mount photovoltaics.
Private, entirely for profit companies, have recently answered large government tenders in the middle east to sell power at the equivalent of $0.05 USD per kWh. They are fairly confident that they can make a profit doing this, even with the cost to incur the long term debt to privately build a massive solar power plant.
The cumulative amount of solar power being produced within Germany right now is a good example of its practical use in a less sunny climate.
In terms of placing things in the ocean, hiring the sort of offshore work vessel with a built-in crane can go and place or remove multi ton apparatus is very costly. Maritime construction for things like laying coastal submarine cable, building piers and docks and marinas, setting and maintaining marker buoys isn't cheap.
Laying and maintaining HV AC or DC submarine cables in salt water is also particularly known to be expensive. Hiring a 36'-42' aluminum landing craft for coastal construction projects, with fuel and crew can be easily $500 an hour.
Labor and vehicle costs are greatly increased compared to doing things on dry land.
I used to think the same way, “just use cheaper solar” but I have come around to see the value. Doing science and engineering projects to explore new or different alternatives is valuable. We might find something surprising.
Having different types of power generation provides redundancy. The wind still blows at night, the tide still comes in and out when its cloudy, etc. Grid storage is nowhere near a solved problem, so something like tidal could prove less expensive than storage or overbuilding alternatives to overcome their variability problems. Even if it doesn’t end up being widely useful, it could still end up finding a use in more niche applications.
Finally, it can and will improve. 30 years ago, solar was not price competitive and decades of development and iterative improvements have changed that. We should keep developing alternatives to see their full potential.
I think the charm for a cloudy place like Scotland is that a system like this is unaffected by poor light supply. Your photovoltaics aren't going to fair nearly so well there hence this solution.
> covering some less-useful land in ground mount photovoltaics.
Doesn't even need to be less-useful land (especially in western Europe, ground is becoming a scarce resource), put PV on flat rooves or add them over open car parks. Also helps alleviate pressure on the overstressed energy grid by generating and using power more locally.
But, local power is (overall) a lot more costly than major centralized power generation projects, like a wind farm or what have you.
* this is a record for the time a turbine has been under the sea without any maintenance, which proves its commercial viability
* because it generates powers during high/low tide, and because the lunar cycle is different to the solar cycle, it could help fill in the parts where solar falls off in a predictable way
BUT:
* Tidal energy is valuable but geographically constrained
* Only a few countries have suitable locations for it (UK, Canada, France, South Korea)
* The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
Plus a newer one off Vancouver island BC shut down after a couple years because its operating costs made it economically infeasible. Had to get fixed and upgraded a few times. Which I why the maintenance thing in the headline is probably relevant.
>* The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
I assume the value is still massive? The UK is still aiming to 4x its Off Shore wind by 2030. That would be 60% of UK electricity. If the new Nuclear Power plant actually deliver double its current 15%, that would be total 90%. The rest could just be solar and underwater turbine.
I am just wondering if underwater turbine causes any issues with marine life. If not we could absolutely deploy them on massive scale and avoid the eye sore of Wind Turbine.
South Korea was going to build a large one but canceled it due to the marine life threat. One way they try to fix it is by having a safety mechanism that turns the blades off when marine life passes through but this increases operating costs on something that is already high maintenance.
"Tidal energy is valuable but geographically constrained" Is this really a negative? Can it not be simply viewed as a boon for places where geographically reasonable? I live in Arizona, I'll not be upset when left out of tidal energy - I've got solar and a sunshine surplus.
the hard part with geographically constrained sources is that they have a harder time getting economies of scale. solar works everywhere and is really easy to install, so the market cap is massive, leading to corresponding increases in production efficiency.
> * Tidal energy is valuable but geographically constrained
Yes, of course. I do not get the point, this is not a solution to every electricity generation problem
> * Only a few countries have suitable locations for it (UK, Canada, France, South Korea)
There are more than that. I have a seven knot tidle current 5km from my house, not mentioned in your list. I know of others. The costal conditions are quite common for this. The same technology will be useful in rivers too
Tides happen everywhere, but not to the same extent and not always at useful times. If your peak production times don't line up with peak demand times, then you need expensive energy storage. (This would change with the phase of the moon, so sometimes you'll get lucky and sometimes you won't.)
One thing that's relatively unique about the UK is that different parts of their coastline experience tides at different phases -- meaning with carefully chosen placement of different tidal energy plants, you can always have some of them operating near peak production. Click around https://www.tidetimes.org.uk and you can find places with high tide times happening at just about any time of day.
If you look at a map like http://www.bidstonobservatory.org.uk/wp-content/uploads/2016..., the best places to use tidal energy would be red areas with lots of white lines hitting the coast -- these would give you the highest-amplitude tides with the most opportunity for phasing. The UK has both.
Most regions have very small tidal ranges. That doesn't mean they have small tidal currents (think of fjords or straights for example), but it does make it more likely.
And in those fjords and straights, I reckon yhese solutions will compete with boat traffic.
> * The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
To put this in perspective, less than 1% of the world's land area would be needed for wind turbines to power the current energy needs of the globe (according to NREL). So this is not a limiting factor.
1% of the world's land surface is massive! That's about 1.5 million square kilometers. That's more than 4 times the land area of Germany or apparently about as much as the entirety of the built up area on Earth.
Not to sound like a crazy person, but, does taking energy from tidal waves mean taking energy from the momentum of the earth itself? I read a long time ago somewhere that if we extract enough tidal energy, the earth's rotation could slow down somehow. Obviously as a layperson on this matter I'm not that well-informed but just curious of the possibilities if anyone knows.
So the lower momentum of the Earth (with a square term) and its (much) higher mass (Moon is 1.2% the mass of Earth) make Earth over 1000 times less energetic. So it's just the Moon that matters here.
Assume every joule extracted is coming directly from that budget and the moving water wasn't going to hit Scotland and turn some into heat anyway. 15.9 TW is average human energy usage.
5.7*10^45J / (15.9 TW * 1 year) = 1.14 * 10^25
So if we generated ALL human power from this method and every joule was taken from the Moon's orbital energy that would otherwise not be taken, we can spin the system down in just over a ten million billion billion years.
This is actually a bit more than I expected, though I knew it would be a lot from basic common sense of 80 billion billion tons moving at 1km/s. So maybe I've flubbed a few (tens of) orders of magnitude? In particular, the 1000:1 Moon:Earth energy ratio sounds plausible when I think about it, but it still was a bit of a surprise.
In any case, I think it's OK.
Edit, OK, so that was bunk, the orbital energy is 3.8×10^28J, so we can unbind the moon and donate it to Jupiter in only 65 million years.
Technically it's the momentum of the earth-moon system; tides are a continuous input of energy into the oceans taken from the rotation of the earth relative to the moon. Tides lose energy to friction. I don't think that increasing tidal friction would have effects back on the planetary system, but it might reduce overall tidal amplitude. Very slightly.
Friction makes the tidal bulges lag slightly, which means they're a little bit ahead of where the moon is. That produces a net acceleration on the moon that raises its orbit. Increasing tidal friction should increase the lag which should increase the speed at which the moon's orbit raises. Completely insignificant at human scale, of course, but technically it should be doing something.
Not in a way that matters (is at all noticeable) until long after the sun expands and wipes out all life on earth in a few billion years. Of course by then, the moon will be quite a bit further from earth than it is today and might become tidally locked with the earth as the earth rotation slows down and eventually matches the speed at which the moon rotates. So there is that.
In the same way, we're not running out of geothermal energy (a tiny part of the heat actually comes from the moon pulling magma around, the rest from radioactive decay and residual hit from when our planet was created). Technically more heat radiates out via our crust naturally than we'll ever need.
So, technically yes but not in a way that actually matters on the time scales we have left on earth, which technically will become a lot more hostile over time anyway. A billion years from now, things will be very much changed here. Minuscule loss of momentum in the moon's orbital movement will be the least of our concerns there.
The 2004 Indian Ocean earthquake and following tsunami shortened Earth's day by 2.68 microseconds. The energy of the tsunami alone was around 4.2E15 joules. Considering Earth's mass, radius and moment of inertia it would take ~2.9E26 joules to shorten the day by 1 minute.
Yes, but tides are already sucking a huge amount of rotational inertia out of the Earth all the time even if we aren't actually using it for any practical purpose. The only reason its not a problem is that the Earth has so much rotational inertia to begin with that it will take a very long time to run out.
I have always had this concern about wind and solar. Removing energy from one part of the earth always sounded very haphazard and untestable.
It's very unclear to me that removing heat from the ground, reducing wind speed/pressure, and lowering tidal forces is guaranteed to never have catastrophic impact.
Do you have this same concern about literally every structure man has ever constructed?
They do the same exact thing in terms of 'slowing wind down' and 'preventing the sun's energy from reaching the ground'.
This idea is understandable, but it falls apart for the same reason the wind turbine bird death concern does (the number of birds that have died due to humans liking windows is 1,000,000x the number that have died in turbines).
With solar humanity's total power consumption is just a fraction of a percent of the Sun's luminance. With wind in some areas you get towards a larger percentage. But either one pales in comparison to the impact of hydropower which has dammed some of the largest rivers and waterfalls in the world to offer only a small fraction of our existing electricity supply.
Its all a question of scale. All these systems can afford some extra energy loss just like the planet could cope with a certain amount of CO2 production because the plants and oceans would grab it and store it. Once we exceed those (currently unknown) limits however it can become a problem and the biggest solar farms are impacting the area around them as they change that energy balance.
You're not removing anything, you're just transforming kinetic energy into electrical energy. Energy transforms, everything transforms on earth, as per the laws of physics. When you die, your body doesn't get "removed", it gets transformed into worm food. It's the cycle of matter and energy. "Yeah science Mr. White!"
I doubt human devices that capture wind and water wave energy are enough to negatively impact the climate in a meaningful way, considering how powerful nature is.
> Removing energy from one part of the earth always sounded very haphazard and untestable.
.. compared to taking energy and carbon from the ground, and changing the atmospheric composition enough to significantly change the temperature? Because that's the alternative to not-renewables.
Yeah everything has an effect. I have been quietly strangling infants in their cots to prevent CO2 increase from their breathing resulting in runaway climate change. We need to take action and stop disrupting a system in homeostasis. We need to go back to the era of 10,000 humans and I volunteer everyone else to sacrifice themselves for my future.
I am extremely skeptical of that 1000 year estimate. It is almost entirely depending on the assumption of the continuous energy increase of 2% per year every year, for the next 1000 years, and that tidal energy remains 1% of that total the entire time.
I think that those assumptions are wrong in multiple ways and that reasonable estimates of the amount of tidal energy that could be extracted would lead to time scales where the risk no longer becomes relevant.
It isn't a mistake to classify it as "renewable" because "renewable" doesn't literally mean until the end of time. Is solar not renewable because the sun will eventually explode? Ridiculous.
And as others have said, 1000 years is a hilariously wrong estimate.
I think if we're positing a world where our energy use increases 2% annually for a thousand years and that tidal power will remain a fixed fraction of that we're not dealing with a reasonable projection. In any event, at the end of those thousand years humanity won't be very far from Dyson Sphere territory and the tidal locking of Earth wouldn't be much of a problem for the civilization implied, but I don't think it's possible to extract tidal energy that fast.
The ocean is brutally unforgiving, and until now the skepticism around durability has been justified. But if projects like MeyGen can show that tidal infrastructure can go the distance, it could unlock a huge untapped energy source
As cool as this sounds, I'm not sure I'm as enthused with stuff our oceans full of more tech, which inevitably will wear down, break, and pollute.
It's better than oil (duh), and something that provides power when solar/wind can't is great (duh). I just wish we would give up on approaches that are basically "If we had a few million of these giga-ton structures all over the ocean, they would provide power equivalent to a few dozen nuclear plants"
Lifecycle analysis is a common and increasingly detailed field which includes impacts to manufacture, transport, install, run, and clean-up installations, either cradle-to-grave, or cradle-to-cradle (includes the cost of recycling). I assume for installations like this, those studies have been done.
There's a whole tirade in "Landman" about wind turbines not being green because of this or that thing[0], ending with the statement: "in its 20-year lifespan, it won't offset the carbon footprint of making it". These are just feelings (of the fictional character, but unfortunately ones adopted by real people) that are unconcerned with the facts that, no, the lifecycle analysis shows that wind turbines break even in 1.8 to 22.5 months, with an average of 5.3 months[1].
And I'm not qualified to say the tidal based solutions will never beat out Geo/Solar/Win + Batteries. In my informed but non-professional opinion, it seems like this avenue will never ever work at scale.
From everything I've seen, we have the answer, we're just stuck under the boot of old money oil barons. Solar + wind + geo (depending on the geographic area) for the majority of our power generation. Nuclear + batteries to smooth out the duck curve form the bottom, paired with more aggressive demand pricing & thermal regulations to smooth it out from the top. That's the answer. But lobbyist's going to lobby.
Yep, lifecycle analysis is the key lens we should be using when evaluating any energy technology, especially in emotionally charged debates about what’s "green" or not
People aren't terribly keen on what happens when nuclear plants inevitably wear down, break or pollute either.
Mind you the market has tended to give up on tidal power too. The sea is a harsh environment, working there is expensive, and solar cost reductions have simply run over most of the competition. Scotland has seen quite a few innovative ocean energy companies launch a pilot, run it for a few years, then go bankrupt.
People are broadly misinformed. Nuclear plants release significantly less radiation than coal based plants, as an example. They do create a lot of waste that we currently don't know how to process, but the quantity is actually shockingly small in the context of a global issue. We're talking several warehouses. Not millions, not all of California. We can just pick some cave in northern Canada or central sahara and bury it there, it seriously isn't that much. It's better than where we currently store the waste which is basically the ocean & clouds.
Meltdowns are tragic when they occur - but rare. It just gets a lot of press when a city of 50k gets deleted than when global ecosystems fail or a billion people die a decade earlier than they otherwise would due to pollution related helath issues.
I like the idea of solar and support it in general, but the implementation is some places is bizarre. Instead of building solar panels over parking lots, putting them on top of buildings, or using them as covers over fields of crops sensitive to sunlight, lots of places have clear cut forests and absolutely covered mountainsides with them. The reason being that it's cheap and out of sight for most people.
The vision now might not be to fill the sea with these turbines. But if it turns out they can be made cheaply and deployed cheaply, easily broken machines that nobody will take responsibility for will definitely be littering the oceans by the millions.
How are concerns about ecological impact misplaced when discussing solutions to ecological problems. It feels pretty relevant to me.
And from everything I've seen/heard, tidal based solutions are just fundamentally incompatible with their product. Keeping sensitive metalic moving parts in saline solution exposed to the sun for years on end - paired with other random things like boating accidents or marine life - it's a non-starter. Constructing these things creates pollution. If it's lifecycle impact is less than oil's, great, I just don't believe we'll ever get to a state where it's better than oil AND (solar/geo/wind) + Batteries.
They're not exactly the same thing but for comparison, France has the Rance Tidal Power Station that has been producing 250MW for 45 years. South Korean made a more powerful one at 254MW. This pilot produced 4.5MW when all 3 turbines were operating normally.
This project is interesting but all comparisons are fair with the end in mind, which is the cost per MWh or per "home" over its life. If you need 55 of those to produce 250MW you'll have to multiply the costs by 55 as well.
Power also has to be available all the time, when there is no sun, no wind, no waves, etc.
Nuclear and gasoline are sadly the top picks because of energy density (and in the case of gasoline also portability).
Rance and Sihwa Lake are different beasts as they require sea walls or dams, which are immensely more expensive and environmentally damaging, and have extremely limited suitable sites worldwide. They would never be built now (Sihwa is only 15 years old, but the seawall was built in 1994). They are essentially low head hydro installations fed by the tidal range.
The installation in the Pentland Firth is a fundamentally different category as it is installed in open water (albeit in a firth or channel) which is much less environmentally impactful and has 2-4 orders of magnitude more suitable sites globally.
The problem here is you have a large body of water that is a huge and significant nursery for fish, and the best place for the turbine is where the water narrows.
If the turbine is a barrier to the fish, (and who knows?), then important fisheries may well collapse
This is an objection that needs to be taken seriously and investigated, so I was disappointed that the article did not address effects on marine life.
Personally I think that the turbines and marine life can co-exist, but we need facts, not reckons
Current energy sources are ~all either from solar radiation (indirectly for fossil fuels) or nuclear fission. Tidal energy is cool because it is to a rough approximation from neither of them!
The real problem: if this technology is viable, it will immediately be attacked with disinformation campaigns (“but it kills dolphins!”), lobbying against it, government red tape, and tariffs.
Solar, wind, and storage can solve most of our energy needs, TODAY, but look at how it’s being treated.
What do these turbines do to Marine life? Fish, dolphins swimming next to the spinning blades. Krill, other micro marine life in the water, disrupted water currents affecting every forms of life?
Because we are not "allowed" to ask these questions, I suspect these environmental efforts are just the vehicles to make money for certain political groups. Just as "freedom on the march" is a vehicle to make money for other groups.
They are still often found at sea. It might have been better to write it's very hard to take what is a wind turbine normally found above water and put it under water.
Or the mouth of an estuary, or an underwater shelf where currents are forced up or down, or any stretch of water with sufficiently high tidal ranges etc.
There are plenty of places where water is naturally under pressure, tidal power is definitely something we should be pushing for more as a species.
Because water is pretty dense, you could in theory get a lot of energy from a relatively small tidal power installation which could be an advantage in some circumstances.
its a visual blight for scuba divers everywhere. it kills millions of fish. the wave patterns caused by the turbine cause chronic headaches for miles. the production process for the turbine actually creates more carbon emissions than just burning the equivalent of coal for 20 years
Maybe these are the windmills that drive the whales crazy? To paraphrase wind-watch.org (sounds non-partisan)
> The obvious concern that most people might guess will be dangerous and damaging to [swimming] wildlife are the spinning blades themselves. While large white spinning [turbine] blades rotating [below] the horizon or in an advertisement seem bucolic, restive, and like the perfect green energy source, the fact is that the tips of the blades can be spinning at up to 200 miles per hour. Those speeding blades can act like a giant blender for large [fish] such as [tuna] and [whales] which fly around the commercial [water] turbines and chop those [fish] up. Biologists have found that even small species of American [fish] regularly get killed from the spinning turbines of commercial [water] turbines.
My intuition is that these will be moving much more slowly than that. The turbines that they refer too are usually high pressure ones designed for generating energy downstream of a huge body of water like a resovoir.
These turbines have a diameter of 18m and a speed of 8 to 20 rpm. So a tip speed of 7.5 to 19 m/s - about 27 kph to 68 kph. I guess that's enough to hurt a whale. Although interestingly the water speed due to the tide in this channel is up to 5 m/s - so maybe it's too turbulent for whales anyway. Do whales like fast flowing water?
Only 1 of the four turbines has been able to operate for 6 years without pulling it out the water. The other 3 have needed costly maintenance https://www.waterpowermagazine.com/news/sae-secures-loan-for...
It's a nice idea but costly compared to solar even in places like Scotland.
This[1] article states the following:
To remind, the MeyGen project’s Phase 1A involved the installation of the AR1500 onto a gravity-based foundation, alongside three other AH1000 MK1 turbines, to form an array of 6MW.
From what I've found, the AR1500 has just had routine quarter-life maintenance[2], but I can't find anything concrete right now which of the four made the 6 year milestone. I do note that in the brochure[3] for the AR1500 they claim three service intervals every 6 1/4 years, rather than four service intervals as indicated by the article.
[1]: https://www.offshore-energy.biz/simec-atlantis-troubleshooti...
[2]: https://www.offshore-energy.biz/overhauled-meygen-turbines-t...
[3]: https://simecatlantis.com/wp-content/uploads/2016/08/AR1500-...
That's useless for commercial operation, but for a trial run perhaps not terrible.
If 1/4 make it then you at least know it can be done and hopefully learned a couple key failure modes from it
If one made it six years, it seems like it should eventually be possible to build turbines that reliably make it that long.
GPs link doesn't even show what was claimed ("The other 3 have needed costly maintenance").
From that link:
"The first of these turbines is scheduled for redeployment in May 2022, with the final turbine to be deployed in March 2023, complete with a retrofitted wet mate connection system, which more than halves the costs of future turbine recoveries and deployments."
"The company’s AR150 turbine was re-deployed last month, after being out of the water for upgrade and maintenance work."
The single long-running turbine can be compared to the upgraded turbines to measure the effect of the upgrades, and it provides the headlines this thread is about. The upgrades themselves are also clearly valuable R&D work.
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Yes, 1 success out of 4 test flights — good news, it's possible!
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That's like saying if I roll 4 dice and one of them lands on a six then it should be possible to make one that only rolls sixes.
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I would love to see a complete cost comparison with solar.
1.5 MW is nothing to scoff at, so if it costs a bit in maintenance that's okay. But overall costs would be great to know.
One benefit that’s difficult to quantify is that the power is extremely predictable compared to other renewables.
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1.5mw is likely a nameplate capacity for the turbine, not the actual output (which should be labeled in GWh per year).
The article likely double-dips on this by saying that 6MW could provide for 7k homes, which it obviously can’t at peak use.
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Also there is theoretically power in the GW range to be harvested here (specifically, Scotland’s tidal flows), so it’s worth investing a substantial sum to figure this tech out.
Texas’ capacity was 113000 MW yesterday so 1.5MW doesn’t seem significant. Am I understanding this wrong?
https://www.ercot.com/gridmktinfo/dashboards
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Even that one proves it's possible, which is huge for an industry that's been stuck in pilot mode for years
> costly maintenance
all systems require maintenance, so "costly" is relative; would need more specifics to determine whether this is a cost effective solution or not
I'm not a turbine, or power generation, expert but I am almost 100% sure that no non-solar power generation method can operate without being taken down periodically for maintenance.
How do the maintenance costs (and intervals) of these compare to gas/steam turbines?
I assume corrosion is to blame? Crazy how much ocean facing stuff is still done with painted steel. You'd think aluminum and carbon fiber or even plastic would be making strides but it's still the iron age in many ways it seems.
Carbon fibres themselves may be corrosion resistent, but the fibers by themselves are like a fabric. If you want a solid part instead of cloth, you need to encase the fibers in a resin. Imagine it like a piece of cloth soaked in beeswax or candle wax: it is solid like the resin but if you pull on it, it has the strength of the fibers of the cloth.
The resins used for carbon fibers are usually very bad at contact with water over long periods of time. Even those in aerospace applications require coating/paint if exposed moisture over time. It’s a plastic, even the best ones don’t do so well in water after a few months.
Furthermore, the damage that moisture does to the resin can be difficult to detect and even more difficult if not impossible to fix. It requires clean rooms, skilled labor and machinery that you don’t have in the middle of an ocean.
Then take iron corrosion: it is easy to spot by naked eye, it may not be easy to repair, but it is relatively simple to “halt” further damage by removing the rust and adding new paint.
Don’t get me wrong: carbon fibers are amazing, but sometimes the “boring” solution is best.
PS: steel alloys and coatings can be amazingly high tech too, it’s amazing what can be engineered.
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All industrial generators undergo regular shutdowns for maintenance and recalibration. This is costly and time consuming when they are on land.
Also, I am thinking about all the ocean factors beyond salt corrosion. There's tons of crap in the water beyond salt and minerals. Like fine grit suspended in it. Plus the tidal forces etc.
Steel has the benefit of fatigue limit. Which means as long as the cyclic stress on steel is under a certain amount it won't fail. Aluminium has a much lower fatigue strength than steel and will always fail given enough cycles.
While rust can be a problem it can be mitigated. Also steel is easier to repair than many other materials (welding).
BTW. Aluminium does suffer from corrosion as well. I used to have racing bike, the wheel nipples (these connect the spokes to the wheel rim) used to corrode to the point where they would fail, which meant I would end up with a buckle. I ended up having both wheel rebuilt with higher quality brass nipples.
Plastics under time also suffers from a different set of issues. Plastics can become brittle. Anyone working on old computers (especially macs) can attest to this.
Corrosion, the force of water (being 800 times as dense as air and effectively incompressible, water forces can be huge), objects in the water (again, water being heavy it can move heavy objects around in its flow), fouling through, for example, algae and mussels (https://en.wikipedia.org/wiki/Fouling)
Carbon fibres tend to crack under extreme torque.
AFAIK corrosion is slower underwater. It’s all the shmutz that’s underwater - logs, rocks and boulders that get moved by these huge tidal currents.
Only 1 of the four turbines has been able to operate for 6 years without pulling it out the water. The other 3 have needed costly maintenance
As opposed to other forms of energy production which have free/zero maintenance?
Well, they just need to use just the ones that don't require maintenance.
Over many years, I've yet to hear of an ocean based power generating system that comes anywhere near the $ per kWh cost produced by just covering some less-useful land in ground mount photovoltaics.
Private, entirely for profit companies, have recently answered large government tenders in the middle east to sell power at the equivalent of $0.05 USD per kWh. They are fairly confident that they can make a profit doing this, even with the cost to incur the long term debt to privately build a massive solar power plant.
The cumulative amount of solar power being produced within Germany right now is a good example of its practical use in a less sunny climate.
In terms of placing things in the ocean, hiring the sort of offshore work vessel with a built-in crane can go and place or remove multi ton apparatus is very costly. Maritime construction for things like laying coastal submarine cable, building piers and docks and marinas, setting and maintaining marker buoys isn't cheap.
Laying and maintaining HV AC or DC submarine cables in salt water is also particularly known to be expensive. Hiring a 36'-42' aluminum landing craft for coastal construction projects, with fuel and crew can be easily $500 an hour.
Labor and vehicle costs are greatly increased compared to doing things on dry land.
I used to think the same way, “just use cheaper solar” but I have come around to see the value. Doing science and engineering projects to explore new or different alternatives is valuable. We might find something surprising.
Having different types of power generation provides redundancy. The wind still blows at night, the tide still comes in and out when its cloudy, etc. Grid storage is nowhere near a solved problem, so something like tidal could prove less expensive than storage or overbuilding alternatives to overcome their variability problems. Even if it doesn’t end up being widely useful, it could still end up finding a use in more niche applications.
Finally, it can and will improve. 30 years ago, solar was not price competitive and decades of development and iterative improvements have changed that. We should keep developing alternatives to see their full potential.
I think the charm for a cloudy place like Scotland is that a system like this is unaffected by poor light supply. Your photovoltaics aren't going to fair nearly so well there hence this solution.
> covering some less-useful land in ground mount photovoltaics.
Doesn't even need to be less-useful land (especially in western Europe, ground is becoming a scarce resource), put PV on flat rooves or add them over open car parks. Also helps alleviate pressure on the overstressed energy grid by generating and using power more locally.
But, local power is (overall) a lot more costly than major centralized power generation projects, like a wind farm or what have you.
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Imagine if we gave up making cars because we had some failures initially. Everything is costly in the beginning.
I did some reading about this yesterday:
* this is a record for the time a turbine has been under the sea without any maintenance, which proves its commercial viability
* because it generates powers during high/low tide, and because the lunar cycle is different to the solar cycle, it could help fill in the parts where solar falls off in a predictable way
BUT:
* Tidal energy is valuable but geographically constrained
* Only a few countries have suitable locations for it (UK, Canada, France, South Korea)
* The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
> Canada
The Annapolis Royal Tidal Station shut down 5 years ago, because it had a strong tendency to chop up all and any fish that went through the intake.
The Annapolis looks like a fundamentally different design: direct turbine driving instead of low-speed / high-torque windmill design.
https://www.youtube.com/watch?v=pxCPXLv--U4&t=71s
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Plus a newer one off Vancouver island BC shut down after a couple years because its operating costs made it economically infeasible. Had to get fixed and upgraded a few times. Which I why the maintenance thing in the headline is probably relevant.
>* The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
I assume the value is still massive? The UK is still aiming to 4x its Off Shore wind by 2030. That would be 60% of UK electricity. If the new Nuclear Power plant actually deliver double its current 15%, that would be total 90%. The rest could just be solar and underwater turbine.
I am just wondering if underwater turbine causes any issues with marine life. If not we could absolutely deploy them on massive scale and avoid the eye sore of Wind Turbine.
South Korea was going to build a large one but canceled it due to the marine life threat. One way they try to fix it is by having a safety mechanism that turns the blades off when marine life passes through but this increases operating costs on something that is already high maintenance.
"Tidal energy is valuable but geographically constrained" Is this really a negative? Can it not be simply viewed as a boon for places where geographically reasonable? I live in Arizona, I'll not be upset when left out of tidal energy - I've got solar and a sunshine surplus.
the hard part with geographically constrained sources is that they have a harder time getting economies of scale. solar works everywhere and is really easy to install, so the market cap is massive, leading to corresponding increases in production efficiency.
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> because it generates powers during high/low tide,
At high and low tide the water isn’t moving much. Surely it generates most at mid tide, with the flow reversing direction causing a lull?
This makes the useful portion of the cycle far far larger.
> * Tidal energy is valuable but geographically constrained
Yes, of course. I do not get the point, this is not a solution to every electricity generation problem
> * Only a few countries have suitable locations for it (UK, Canada, France, South Korea)
There are more than that. I have a seven knot tidle current 5km from my house, not mentioned in your list. I know of others. The costal conditions are quite common for this. The same technology will be useful in rivers too
It will be a far higher proportion in the countries where there are suitable locations.
it is predictable and reliable, so has significant advantages over wind.
Quite possibly, with a suitable distribution of sites around the UK coast, the total power generation might be nearly constant over time.
A guaranteed minimum power generation would presumably be very useful.
> Tidal energy is valuable but geographically constrained
Don't tides happen everywhere there is a coast (which is a lot of places)? Or is this only effective in certain tidal conditions?
Tides happen everywhere, but not to the same extent and not always at useful times. If your peak production times don't line up with peak demand times, then you need expensive energy storage. (This would change with the phase of the moon, so sometimes you'll get lucky and sometimes you won't.)
One thing that's relatively unique about the UK is that different parts of their coastline experience tides at different phases -- meaning with carefully chosen placement of different tidal energy plants, you can always have some of them operating near peak production. Click around https://www.tidetimes.org.uk and you can find places with high tide times happening at just about any time of day.
If you look at a map like http://www.bidstonobservatory.org.uk/wp-content/uploads/2016..., the best places to use tidal energy would be red areas with lots of white lines hitting the coast -- these would give you the highest-amplitude tides with the most opportunity for phasing. The UK has both.
The issue is clarified with a map like this: https://i.redd.it/rontertecjqd1.jpeg
Most regions have very small tidal ranges. That doesn't mean they have small tidal currents (think of fjords or straights for example), but it does make it more likely.
And in those fjords and straights, I reckon yhese solutions will compete with boat traffic.
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> * The Global Technical Potential (in TWh/year) is 1/10th of offshore wind
To put this in perspective, less than 1% of the world's land area would be needed for wind turbines to power the current energy needs of the globe (according to NREL). So this is not a limiting factor.
1% of the world's land surface is massive! That's about 1.5 million square kilometers. That's more than 4 times the land area of Germany or apparently about as much as the entirety of the built up area on Earth.
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So we would need to cover 4% (1% * 10 GTP * 30% land / 70% water) of the ocean to power the world? Seems like a lot
Not to sound like a crazy person, but, does taking energy from tidal waves mean taking energy from the momentum of the earth itself? I read a long time ago somewhere that if we extract enough tidal energy, the earth's rotation could slow down somehow. Obviously as a layperson on this matter I'm not that well-informed but just curious of the possibilities if anyone knows.
The momentum of the Earth-moon system is 3.61x10^34 kg.m^2/s, of which 80% is the moon orbiting and 20% is the Earth (https://space.stackexchange.com/questions/50502/how-much-of-...).
KE = p^2 / 2m
Energy in the Moon's orbit: 5.7*10^45J
Energy in the Earth's orbit: 4.4*10^42J
So the lower momentum of the Earth (with a square term) and its (much) higher mass (Moon is 1.2% the mass of Earth) make Earth over 1000 times less energetic. So it's just the Moon that matters here.
Assume every joule extracted is coming directly from that budget and the moving water wasn't going to hit Scotland and turn some into heat anyway. 15.9 TW is average human energy usage.
5.7*10^45J / (15.9 TW * 1 year) = 1.14 * 10^25
So if we generated ALL human power from this method and every joule was taken from the Moon's orbital energy that would otherwise not be taken, we can spin the system down in just over a ten million billion billion years.
This is actually a bit more than I expected, though I knew it would be a lot from basic common sense of 80 billion billion tons moving at 1km/s. So maybe I've flubbed a few (tens of) orders of magnitude? In particular, the 1000:1 Moon:Earth energy ratio sounds plausible when I think about it, but it still was a bit of a surprise.
In any case, I think it's OK.
Edit, OK, so that was bunk, the orbital energy is 3.8×10^28J, so we can unbind the moon and donate it to Jupiter in only 65 million years.
The real question is much energy do we need to harvest to slow down the moon's orbit enough to get exactly 12 lunar months per year?
EDIT: and can we also simultaneously slow down the Earth's rotation to have exactly 360 days per year? Fix the calendar once and for all.
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> "So maybe I've flubbed a few (tens of) orders of magnitude?"
Yeah, a few tens! Part of it is that you seem to have reinterpreted angular momentum as linear momentum. That's not dimensionally cromulent.
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Technically it's the momentum of the earth-moon system; tides are a continuous input of energy into the oceans taken from the rotation of the earth relative to the moon. Tides lose energy to friction. I don't think that increasing tidal friction would have effects back on the planetary system, but it might reduce overall tidal amplitude. Very slightly.
Friction makes the tidal bulges lag slightly, which means they're a little bit ahead of where the moon is. That produces a net acceleration on the moon that raises its orbit. Increasing tidal friction should increase the lag which should increase the speed at which the moon's orbit raises. Completely insignificant at human scale, of course, but technically it should be doing something.
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We have reduced tidal friction much more significantly by removing mangroves and killing coral reefs, general coastal buildup.
Earth's rotation is already slowing down because of 'tidal drag' by about 1..2ms per century (but surprisingly, also speeding up since recently):
https://en.wikipedia.org/wiki/Earth%27s_rotation
Not in a way that matters (is at all noticeable) until long after the sun expands and wipes out all life on earth in a few billion years. Of course by then, the moon will be quite a bit further from earth than it is today and might become tidally locked with the earth as the earth rotation slows down and eventually matches the speed at which the moon rotates. So there is that.
In the same way, we're not running out of geothermal energy (a tiny part of the heat actually comes from the moon pulling magma around, the rest from radioactive decay and residual hit from when our planet was created). Technically more heat radiates out via our crust naturally than we'll ever need.
So, technically yes but not in a way that actually matters on the time scales we have left on earth, which technically will become a lot more hostile over time anyway. A billion years from now, things will be very much changed here. Minuscule loss of momentum in the moon's orbital movement will be the least of our concerns there.
Given the current rate of development, it probably won't be an issue for a while.
Why the downvotes?
The 2004 Indian Ocean earthquake and following tsunami shortened Earth's day by 2.68 microseconds. The energy of the tsunami alone was around 4.2E15 joules. Considering Earth's mass, radius and moment of inertia it would take ~2.9E26 joules to shorten the day by 1 minute.
It seems it really won't be an issue for a while.
Conservation of angular momentum says no. Energy, momentum and angular momentum each have their own conservation laws.
Edit: although maybe it could facilitate transfer of angular momentum between Earth rotation and the moon's orbital motion.
There are conversions between each.
Yes, but tides are already sucking a huge amount of rotational inertia out of the Earth all the time even if we aren't actually using it for any practical purpose. The only reason its not a problem is that the Earth has so much rotational inertia to begin with that it will take a very long time to run out.
https://cs.stanford.edu/people/zjl/pdf/tide.pdf
I have always had this concern about wind and solar. Removing energy from one part of the earth always sounded very haphazard and untestable.
It's very unclear to me that removing heat from the ground, reducing wind speed/pressure, and lowering tidal forces is guaranteed to never have catastrophic impact.
Do you have this same concern about literally every structure man has ever constructed?
They do the same exact thing in terms of 'slowing wind down' and 'preventing the sun's energy from reaching the ground'.
This idea is understandable, but it falls apart for the same reason the wind turbine bird death concern does (the number of birds that have died due to humans liking windows is 1,000,000x the number that have died in turbines).
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Wind turbines can have local effects, meaning less wind in areas behind the turbines, which can mean smog stays longer in a city.
But like the other comment said, with solar you are not taking anything.
But solar panels do heat up the air around them more than vegetation would do.
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With solar humanity's total power consumption is just a fraction of a percent of the Sun's luminance. With wind in some areas you get towards a larger percentage. But either one pales in comparison to the impact of hydropower which has dammed some of the largest rivers and waterfalls in the world to offer only a small fraction of our existing electricity supply.
Its all a question of scale. All these systems can afford some extra energy loss just like the planet could cope with a certain amount of CO2 production because the plants and oceans would grab it and store it. Once we exceed those (currently unknown) limits however it can become a problem and the biggest solar farms are impacting the area around them as they change that energy balance.
At this point i think removing any heat from ground is a net win.
Solar is just transforming light into electricity, i don’t think it’s removing any heat from the system unfortunately, unlike radiative cooling paint.
Now that we should be painting any tropical building we can with.
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>removing heat from the ground
You're not removing anything, you're just transforming kinetic energy into electrical energy. Energy transforms, everything transforms on earth, as per the laws of physics. When you die, your body doesn't get "removed", it gets transformed into worm food. It's the cycle of matter and energy. "Yeah science Mr. White!"
I doubt human devices that capture wind and water wave energy are enough to negatively impact the climate in a meaningful way, considering how powerful nature is.
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Strictly speaking nothing, including posting HN comments, is guaranteed to never have catastrophic impact.
We all need to live with some calculated risks.
> Removing energy from one part of the earth always sounded very haphazard and untestable.
.. compared to taking energy and carbon from the ground, and changing the atmospheric composition enough to significantly change the temperature? Because that's the alternative to not-renewables.
Yeah everything has an effect. I have been quietly strangling infants in their cots to prevent CO2 increase from their breathing resulting in runaway climate change. We need to take action and stop disrupting a system in homeostasis. We need to go back to the era of 10,000 humans and I volunteer everyone else to sacrifice themselves for my future.
That's correct, while clean it'd be a mistake to classify it as "renewable".
https://cs.stanford.edu/people/zjl/pdf/tide.pdf is a pretty accessible entry.
I am extremely skeptical of that 1000 year estimate. It is almost entirely depending on the assumption of the continuous energy increase of 2% per year every year, for the next 1000 years, and that tidal energy remains 1% of that total the entire time.
I think that those assumptions are wrong in multiple ways and that reasonable estimates of the amount of tidal energy that could be extracted would lead to time scales where the risk no longer becomes relevant.
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It isn't a mistake to classify it as "renewable" because "renewable" doesn't literally mean until the end of time. Is solar not renewable because the sun will eventually explode? Ridiculous.
And as others have said, 1000 years is a hilariously wrong estimate.
I think if we're positing a world where our energy use increases 2% annually for a thousand years and that tidal power will remain a fixed fraction of that we're not dealing with a reasonable projection. In any event, at the end of those thousand years humanity won't be very far from Dyson Sphere territory and the tidal locking of Earth wouldn't be much of a problem for the civilization implied, but I don't think it's possible to extract tidal energy that fast.
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On the timescales involved here, there is no such thing as renewable energy.
The ocean is brutally unforgiving, and until now the skepticism around durability has been justified. But if projects like MeyGen can show that tidal infrastructure can go the distance, it could unlock a huge untapped energy source
As cool as this sounds, I'm not sure I'm as enthused with stuff our oceans full of more tech, which inevitably will wear down, break, and pollute.
It's better than oil (duh), and something that provides power when solar/wind can't is great (duh). I just wish we would give up on approaches that are basically "If we had a few million of these giga-ton structures all over the ocean, they would provide power equivalent to a few dozen nuclear plants"
Lifecycle analysis is a common and increasingly detailed field which includes impacts to manufacture, transport, install, run, and clean-up installations, either cradle-to-grave, or cradle-to-cradle (includes the cost of recycling). I assume for installations like this, those studies have been done.
There's a whole tirade in "Landman" about wind turbines not being green because of this or that thing[0], ending with the statement: "in its 20-year lifespan, it won't offset the carbon footprint of making it". These are just feelings (of the fictional character, but unfortunately ones adopted by real people) that are unconcerned with the facts that, no, the lifecycle analysis shows that wind turbines break even in 1.8 to 22.5 months, with an average of 5.3 months[1].
[0]: https://www.youtube.com/watch?v=wBC_bug5DIQ
[1]: https://pubs.acs.org/doi/full/10.1021/acs.est.9b01030
Yes, lifecycle analysis is the holy grail.
And I'm not qualified to say the tidal based solutions will never beat out Geo/Solar/Win + Batteries. In my informed but non-professional opinion, it seems like this avenue will never ever work at scale.
From everything I've seen, we have the answer, we're just stuck under the boot of old money oil barons. Solar + wind + geo (depending on the geographic area) for the majority of our power generation. Nuclear + batteries to smooth out the duck curve form the bottom, paired with more aggressive demand pricing & thermal regulations to smooth it out from the top. That's the answer. But lobbyist's going to lobby.
Yep, lifecycle analysis is the key lens we should be using when evaluating any energy technology, especially in emotionally charged debates about what’s "green" or not
People aren't terribly keen on what happens when nuclear plants inevitably wear down, break or pollute either.
Mind you the market has tended to give up on tidal power too. The sea is a harsh environment, working there is expensive, and solar cost reductions have simply run over most of the competition. Scotland has seen quite a few innovative ocean energy companies launch a pilot, run it for a few years, then go bankrupt.
People are broadly misinformed. Nuclear plants release significantly less radiation than coal based plants, as an example. They do create a lot of waste that we currently don't know how to process, but the quantity is actually shockingly small in the context of a global issue. We're talking several warehouses. Not millions, not all of California. We can just pick some cave in northern Canada or central sahara and bury it there, it seriously isn't that much. It's better than where we currently store the waste which is basically the ocean & clouds.
Meltdowns are tragic when they occur - but rare. It just gets a lot of press when a city of 50k gets deleted than when global ecosystems fail or a billion people die a decade earlier than they otherwise would due to pollution related helath issues.
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How much will it pollute compared to other technologies? That’s the question to ask.
Thermal plants like coal and nuclear need cooling water, the output of which ends up in the sea too
Anything that stops people fishing a part of the sea is probably a good thing for the environment.
But I don't think the vision here is to fill the seas with millions of machines.
I like the idea of solar and support it in general, but the implementation is some places is bizarre. Instead of building solar panels over parking lots, putting them on top of buildings, or using them as covers over fields of crops sensitive to sunlight, lots of places have clear cut forests and absolutely covered mountainsides with them. The reason being that it's cheap and out of sight for most people.
The vision now might not be to fill the sea with these turbines. But if it turns out they can be made cheaply and deployed cheaply, easily broken machines that nobody will take responsibility for will definitely be littering the oceans by the millions.
This is such a misguided concern I'm wondering if you are concern trolling...
How are concerns about ecological impact misplaced when discussing solutions to ecological problems. It feels pretty relevant to me.
And from everything I've seen/heard, tidal based solutions are just fundamentally incompatible with their product. Keeping sensitive metalic moving parts in saline solution exposed to the sun for years on end - paired with other random things like boating accidents or marine life - it's a non-starter. Constructing these things creates pollution. If it's lifecycle impact is less than oil's, great, I just don't believe we'll ever get to a state where it's better than oil AND (solar/geo/wind) + Batteries.
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They're not exactly the same thing but for comparison, France has the Rance Tidal Power Station that has been producing 250MW for 45 years. South Korean made a more powerful one at 254MW. This pilot produced 4.5MW when all 3 turbines were operating normally.
This project is interesting but all comparisons are fair with the end in mind, which is the cost per MWh or per "home" over its life. If you need 55 of those to produce 250MW you'll have to multiply the costs by 55 as well. Power also has to be available all the time, when there is no sun, no wind, no waves, etc. Nuclear and gasoline are sadly the top picks because of energy density (and in the case of gasoline also portability).
Rance and Sihwa Lake are different beasts as they require sea walls or dams, which are immensely more expensive and environmentally damaging, and have extremely limited suitable sites worldwide. They would never be built now (Sihwa is only 15 years old, but the seawall was built in 1994). They are essentially low head hydro installations fed by the tidal range.
The installation in the Pentland Firth is a fundamentally different category as it is installed in open water (albeit in a firth or channel) which is much less environmentally impactful and has 2-4 orders of magnitude more suitable sites globally.
We have debate around this in New Zealand
The problem here is you have a large body of water that is a huge and significant nursery for fish, and the best place for the turbine is where the water narrows.
If the turbine is a barrier to the fish, (and who knows?), then important fisheries may well collapse
This is an objection that needs to be taken seriously and investigated, so I was disappointed that the article did not address effects on marine life.
Personally I think that the turbines and marine life can co-exist, but we need facts, not reckons
One thing is not immediately obvious is just how hostile that area is.
Firstly sea water is corrosive, plus if you add all the sand and other particles that are in there it becomes abrasive as well.
BUT
the tide also reaches speeds of 30kmh (18mph) twice a day.
Where I live there's a tidemill that's been running for 850 years.
Still provides power today.
Recently saw this design where it's a ball going up and down with a chamber inside, wonder how that will fair out
https://www.youtube.com/watch?v=Q7Pmgq2JKbI
Current energy sources are ~all either from solar radiation (indirectly for fossil fuels) or nuclear fission. Tidal energy is cool because it is to a rough approximation from neither of them!
The real problem: if this technology is viable, it will immediately be attacked with disinformation campaigns (“but it kills dolphins!”), lobbying against it, government red tape, and tariffs.
Solar, wind, and storage can solve most of our energy needs, TODAY, but look at how it’s being treated.
What do these turbines do to Marine life? Fish, dolphins swimming next to the spinning blades. Krill, other micro marine life in the water, disrupted water currents affecting every forms of life?
Because we are not "allowed" to ask these questions, I suspect these environmental efforts are just the vehicles to make money for certain political groups. Just as "freedom on the march" is a vehicle to make money for other groups.
Who said you were not allowed to ask these questions?
Downvoting that you can observe in real-time.
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> It’s very hard to take what is essentially a wind turbine normally found on land
To be pedantic, a lot of wind turbines are placed out at sea.
The full quote is:
> It’s very hard to take what is essentially a wind turbine normally found on land and put it under water
With that context your comment looks pretty silly, no?
They are still often found at sea. It might have been better to write it's very hard to take what is a wind turbine normally found above water and put it under water.
Nice.
Tidal power only works where the geography is right. A bay with a choke point to the ocean, like this one, is needed.
Or the mouth of an estuary, or an underwater shelf where currents are forced up or down, or any stretch of water with sufficiently high tidal ranges etc.
There are plenty of places where water is naturally under pressure, tidal power is definitely something we should be pushing for more as a species.
Aren’t we just picking up Pennys when solar and wind are available?
Because water is pretty dense, you could in theory get a lot of energy from a relatively small tidal power installation which could be an advantage in some circumstances.
I wish they provided pics of one underwater. I love stuff that invokes a feeling of submechanophobia
Yeah, there's something weirdly mesmerizing and terrifying about giant machines lurking underwater
It will be interesting to see how the right disparages this form of non-fossil fuel based electricity generation.
its a visual blight for scuba divers everywhere. it kills millions of fish. the wave patterns caused by the turbine cause chronic headaches for miles. the production process for the turbine actually creates more carbon emissions than just burning the equivalent of coal for 20 years
Sounds like they need to get the quality control down pat if only 1 out of 4 of the turbines achieved this goal - still a promising milestone, though.
Engineering for machines underwater is tough because the environment is extremely hostile. For a test bed device, 25% success is very good.
Upgrades and changes are mentioned, so it’s not clear that reliability is the only cause of downtime.
See also the Scottish company Orbital Marine Energy with their really cool floating design: https://o2-x.orbitalmarine.com/
I believe they specifically designed it to simplify maintenance
Maybe these are the windmills that drive the whales crazy? To paraphrase wind-watch.org (sounds non-partisan)
> The obvious concern that most people might guess will be dangerous and damaging to [swimming] wildlife are the spinning blades themselves. While large white spinning [turbine] blades rotating [below] the horizon or in an advertisement seem bucolic, restive, and like the perfect green energy source, the fact is that the tips of the blades can be spinning at up to 200 miles per hour. Those speeding blades can act like a giant blender for large [fish] such as [tuna] and [whales] which fly around the commercial [water] turbines and chop those [fish] up. Biologists have found that even small species of American [fish] regularly get killed from the spinning turbines of commercial [water] turbines.
/s
My intuition is that these will be moving much more slowly than that. The turbines that they refer too are usually high pressure ones designed for generating energy downstream of a huge body of water like a resovoir.
Did you just post a wind-turbine criticism?
These turbines have a diameter of 18m and a speed of 8 to 20 rpm. So a tip speed of 7.5 to 19 m/s - about 27 kph to 68 kph. I guess that's enough to hurt a whale. Although interestingly the water speed due to the tide in this channel is up to 5 m/s - so maybe it's too turbulent for whales anyway. Do whales like fast flowing water?
this feels solvable with a cage around like you have on every pedestal fan?
that reads as nonsense. it's mixing wind and water, and all those missing words indicate that it's the product of a broken mind.
also, you, the MAGA-hallucinations against windpower are contemptible lies AND they have nothing to do with this single underwater turbine.
[dead]
Out of sight, out of mind...
Caution, by harvesting tidal energy you're tapping into the potential energy of the Moon, making it move closer to us at an increased speed.
Doesn’t the moon move away from us?
https://public.nrao.edu/ask/what-happens-as-the-moon-moves-a...
Surely taking energy from it would make it move further away?