I was hoping for some sort of diagram or animation about what this thing is set up and does underwater and how this movement gets converted to electricity. Does anybody know?
28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
51–60 of 192 posts
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#52Earlier quoted context omitted.
The good news is that we do have a bit of experience with metal machines that operate in sea water for decades. We (as in humanity, I don't) know exactly what to expect. You'd want to have a permanent service operation scaled exactly to how much overhauling capacity you need to put the tide kites in a round robin maintenance loop.
And yet, every other tidal powerplant has been rendered hopelessly useless by barnacles.
Have they? And how many of them can be ordered to surface under tide power, for easy maintenance access and towing into a maintenance dock without involving expensive divers?
I presume the tether on this would be built long enough for controlled surfacing, a longer tether means larger deadzone between inbound and outbound tide, but there won't be much energy in the flow close to the turning point anyways.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#53I was hoping for some sort of diagram or animation about what this thing is set up and does underwater and how this movement gets converted to electricity. Does anybody know?
Check out the embedded video in the story (link: https://www.youtube.com/watch?v=dkXinDn67Kw )
The turbine (propeller) at the back of the kite rotates and generates electricity.
Since this can 'fly' at an angle to the current, the speed of the 'kite' moving through the water, will be faster than the movement of the water - therefore the turbine can be spun faster than if it were just anchored in one spot.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#54Too good to be true? I assume this does no harm to fish. And electricity can be easily transported back to land ( there was no mention of how this was done in the video ). Since it is portable, small, fits into a 40ft Container. And you could mass manufacture these, ship it with container. There isn't another manufacturing problem and transportation problem like wind turbine. If Yes. You could have tens of thousands…
> Surely there has to be a catch somewhere. Right?
Underwater things are expensive to maintain, nothing is 100% waterproof, so rust rust rust.
Underwater cables are no joke either, especially if you're building a network of sea cables. Making watertight is not cheap.
And there is the question of doing high power electricity under seawater. I'm not an engineer in that field, that I think it is going to being a whole lot of new headaches.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#55Since the number 1.2MW didn't mean much to me, modern on-shore wind turbines seem to supply 3-4MW and offshore ones 8 - 12MW. But this seems a lot easier to transport and install compared to cranes and the nightmare of navigating turbine blades on trucks through places. And if these hold up to water and don't cause too many problems for wildlife, there would be a lot less discussions about these "messing up my skylin…
A kettle uses ~1.5KW, a geyser ~2KW, an oven ~5KW, a stove about ~3KW. These are fairly high estimates I got from some quick googling. If you add these all up, and account for some more appliances (HVAC, fridge/freezer etc.), I think it is safe to estimate that a household less than 20KW at peak, even though it is a fairly high estimate.
So going backwards from there, 1.2MW = 1200KW and 1200KW / 20KW = 60 households at peak usage. Which is a very conservative estimate.
For future reference I will use 1MW = 50 households as a conservative rule of thumb. Maybe 100 households per MW is closer to reality, but that feels fairly lenient to me.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#56More renewable is good.. but there is always one fear in my crazy mind about these: This isn't actually renewable but taking energy out of a huge reservoir (Same for solar if pea counting, but solar is really endless until the end of the solar system).. and if we'd scale it massively the result could be another catastrophe. (Same btw. with geothermal?). (Btw.. I maybe got tidal wrong, so if it is just taking energy f…
> Same for solar if pea counting, but solar is really endless until the end of the solar system Imagine you wrap the Earth inside a sphere of perfectly efficient solar panels, that would be energetically troublesome! Every bit of solar panel we lay removes a bit of that overall energy flux; the question is then how much can we afford without detrimental impact. Essentially we dampen tides with these devices. Windmill…
I think you're assuming renewable means infinite.
> - nuclear
Nuclear isn't renewable, but there's a huge amount of it and it doens't have the same problems.
> (and so the sun) is not renewable:
The energy we get from it is. It's not a fixed resource that we're depleting. When we burn all the coal, it's gone. Tomorrow there will be more sunlight. We're not cutting chunks off of the sun to get energy for solar.
> - fossil fuel is renewable... on a geological timescale,
Only some of them, and only if we change the definition of renewable. Coal is there because there weren't fungi that could break down lignin at the time.
> Imagine you wrap the Earth inside a sphere of perfectly efficient solar panels, that would be energetically troublesome! Every bit of solar panel we lay removes a bit of that overall energy flux; the question is then how much can we afford without detrimental impact.
We could probably benefit significantly with reducing the energy flux right now.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#57Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#58More renewable is good.. but there is always one fear in my crazy mind about these: This isn't actually renewable but taking energy out of a huge reservoir (Same for solar if pea counting, but solar is really endless until the end of the solar system).. and if we'd scale it massively the result could be another catastrophe. (Same btw. with geothermal?). (Btw.. I maybe got tidal wrong, so if it is just taking energy f…
Alien archeologists from the future: "Earthlings caused a catastrophe by trying to suck every bit of tidal energy. Via tidal acceleration[^1], they made their natural satellite fall into their planet. The curious thing is that the kind of planetary technology level they deployed to extract energy from the tides was more than enough to build huge rotating habitats, which they even knew of and called O'Neill cylinders[^2]. But Earthlings called names anybody proposing the idea, and it never really took off before their moon fell on their heads. This is a textbook case of how a civilization's culture affects their development."
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#59More renewable is good.. but there is always one fear in my crazy mind about these: This isn't actually renewable but taking energy out of a huge reservoir (Same for solar if pea counting, but solar is really endless until the end of the solar system).. and if we'd scale it massively the result could be another catastrophe. (Same btw. with geothermal?). (Btw.. I maybe got tidal wrong, so if it is just taking energy f…
How would solar be the same? That "reservoir" is emptying wether we hold silicon into the photon flow or not. Tides and wind aren't quite as far from just taking what is already disappearing, but even there: the natural drag of land and sea floor shapes is not only so many more orders of magnitude larger than anything we could ever build, there's also the nonlinearity of drag, if we slow down the natural flow a tiny little but the effect of natural drag will decrease accordingly and the total difference to natural flow will be much smaller than it would be if drag was linear to speed.
Re: 28-ton, 1.2-megawatt tidal kite is now exporting power to the grid
#60Earlier quoted context omitted.
> If we are being reckless and just want to use power until we figure out nuclear fusion or something better, let's say a million years or so, we can make some 180 PW from tides. But since it would almost all turn to heat, and since that is more energy than the Earth gets from the Sun, that would probably be unwise unless we find a way to get it off-planet with very high efficiency. I think you're touching on the pro…
I'm not sure those considerations are applicable. There is no "ecosystem" that depends on the rate of slowdown of Earth's rotation - we do need to leave some rotation to keep flora and fauna alive, but that's a "reservoir" problem, to use the OP's formulation, not an intensity one. As for the addition of energy (heat) to the planet, sure, but there's nothing specific about tidal energy here. All energy sources except…
Also worth noting that trying to extrapolate the effects of current technology at this timescale is pointless.
There will be tide changes in human’s technological capabilities long before there could be any reckoning for over-extraction of the Earth’s rotational energy.
For example, in our ability to bring mass into orbit. Add a couple orders of magnitude in that capability, and humans can start directly tuning the Earth’s total solar irradiance by shooting lunar dust into a Lagrange point, reducing the amount of sunlight hitting the Earth by fractions of a percentage.
The Lagrange point is not perfectly stable, so the dust naturally dissipates over a 10-20 year timescale. If you don’t keep sending more dust, the “planetary sun-shade” naturally dissipates, so there’s zero risk of overdoing it.
Basically, within the next ~50 years, I predict we will gain the ability to turn down the planet’s thermostat in a very safe and predictable fashion, without having to pollute our own stratosphere. Overheating the planet becomes a total non-issue.