41–50 of 192 posts
How on earth can such a small device generate so much energy? Wouldn't 1.2 MW of power make it very brittle just like a real kite? Or else why not scale it up and make one 100 times larger that generates 120 MW of power? Since tidal currents are much more reliable (I think) than offshore wind it almost seem to good to be true. There has to be a catch.
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 of these in north of Scotland of or seas around England.
Surely there has to be a catch somewhere. Right?
More 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…
Some numbers here: https://en.wikipedia.org/wiki/Tidal_power#Principle (last paragraph). Tidal energy is wasted by natural coastlines all the time, being converted into heat and erosion. If this effect is constant, it looks like the day gets longer by 7 minutes 12 seconds every 36.5 million years. (I calculated that because it's a 1% reduction in rotational energy.) Human extraction of tidal energy is much smaller th…
Earlier quoted context omitted.
> Probably the biggest issues I could imagine are maintenance and wildlife. They might be minor issues though. Might, yes, but I think it’s unlikely all problems will be minor. Salt water isn’t kind to metal, no matter how well painted. Also, I expect barnacles will start growing on it. If you’re a filter feeder, this may be even better than sitting on the sea bed or on a whale. Question will be how much that effects…
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.
Earlier quoted context omitted.
It's good that you are aware it's a crazy thought :) Nothing wrong with looking into it though. Wikipedia offers: > Movement of tides causes a loss of mechanical energy in the Earth-Moon system: this results from pumping of water through natural restrictions around coastlines and consequent viscous dissipation at the seabed and in turbulence. This loss of energy has caused the rotation of the Earth to slow in the 4.5…
> 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…
As for the addition of energy (heat) to the planet, sure, but there's nothing specific about tidal energy here. All energy sources except solar (and wind/hydro which are direct solar derivatives) add heat to the planet that would otherwise have stayed sequestered. But it's many orders of magnitude less than the heating from solar energy, which is why increasing Earth's absorption factor by a few points is an infinitely bigger problem than all the energy we are directly producing or can hope to directly produce in the next few centuries.
More 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…
Tidal energy comes from the moon (and the sun) pulling the oceans as the Earth spins. Extracting energy from this effectively increases the drag between the ocean and the land, which slows down the rotation of the Earth. This effect even occurs without extracting tidal energy, and some of the dinosaurs (IIRC) had 19 hour days. The amount of energy in the rotation of the Earth is so huge that this basically doesn't ma…
A. Build some huge-ass rockets on the moon to accelerate it to offset any slowdown from changes in tidal energy.
B. Divert a few billion tonnes of asteroids to crash into the moon's aft, adding both to the moon's velocity and mass.
I believe that if we begin working on any of these solutions within a hundred thousand years or so from now we should be able to offset most of the projected long-term lengthening of the day.
Definitely seems more feasible than a lot of crazy energy ideas! E.g. I think this makes more sense than the air versions because you don't have problems launching/landing or when the wind stops. Probably the biggest issues I could imagine are maintenance and wildlife. They might be minor issues though. Also in most of the world (maybe not the Faroe Islands) this has to compete with solar & batteries which are gettin…
Solar will probably be far cheaper per installed MW (although capacity factor will be much lower), but batteries are still a long way from being cost effective. The cheapest batteries right now cost $100/kWh or $100k/MWh. Battery costs are still falling, but the curve is levelling off.
That price means that time-shifting 1 MWh of energy a day for 10 years would add $27 per MWh to the cost of electricity (ignoring ongoing maintenance costs, and assuming a 1MWh battery can do 4k cycles). The company behind this is forecasting $50/MWh of generation. Solar on its own right now sits at $30/MWh, although presumably that's for places with relatively high capacity factors.
The limitations are obvious - this is very geographically constrained. I suspect there will be a small place for this type of technology in the renewable mix - especially in remote and northern places. Then again, offshore wind is already sitting at below $50/MWh and doesn't have the same geographic constraints - so maybe it's a better bet.
Earlier quoted context omitted.
Some numbers here: https://en.wikipedia.org/wiki/Tidal_power#Principle (last paragraph). Tidal energy is wasted by natural coastlines all the time, being converted into heat and erosion. If this effect is constant, it looks like the day gets longer by 7 minutes 12 seconds every 36.5 million years. (I calculated that because it's a 1% reduction in rotational energy.) Human extraction of tidal energy is much smaller th…
Erosion is not always wastage.
Too 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…
Never mind that if CO2 in the atmosphere continues to climb, all those birds will die anyway, the global food ecosystem will go crazy, hundreds of millions of people will die and so on: that picturesque estuary has to remain unencumbered with man-made engineering, or else!