Obtaining sustainable electrical energy from marine currents
Just as there are air currents that move wind turbines and produce electrical energy, there are underwater currents that until now have been unused. One of the strongest sea currents passes near the coast of Japan, and they call it the Kuroshio Current, and there they intend to take advantage of it.
Ocean currents are caused by differences in salinity, terrestrial rotation, temperature differences, etc…
At the poles, part of the water freezes, but the ice that forms has no salt, and the remaining water is saltier and denser, so it sinks to the bottom and then flows to other areas near the equator.
And something important is that these ocean currents are quite stable, apart from being with us for many thousands of years.
It should also be noted that these underwater currents are each larger than thousands of rivers together, and that underwater movement, which is quite constant, can be used to move turbines placed at a certain depth (about 100 meters below the surface.) and produce electrical energy.
In Japan they have made a double turbine at the prototype level that was capable of generating 100 Kwh. They have had it operating under water for three and a half years and the results have been more than positive. Below you can see a schematic photo.
The turbines are anchored to the bottom of the sea and are placed at a depth of about 100 m, so they do not affect maritime traffic, nor are they visible to the eye, as indicated in the following photo.
The generated energy is carried by cables to the ground, and in case of need to do maintenance, the turbines can be placed on the surface to work better on them.
The next phase (phase 2) will be to build a first operating system with 40-meter turbines, which will generate 2 MWh of energy, and later, in phase three, place 100 double turbines that are capable of generating 200 MWh., that can feed more than 3,000 homes.
These turbines are slower than wind turbines so that they affect marine species less, and they have to check that the little noise they generate does not affect the cetaceans that pass through the area.
There is still a lot of work to be done before we can say that it is a viable system for sustainable electricity generation, but the idea seems very good, and fully compatible with solar and wind generation.
From the studies done on the Kuroshio Current that passes through Japan, they believe that they can get more than 200 GWh from it, which is more than half of all the energy that Japan needs.
There are other marine currents in other parts of the world, and it is more than likely that this type of energy can be obtained in other places, but good international cooperation would be necessary for that.
The energy challenge, like global warming, is a global phenomenon. And so it should be focused so that it is resolved in the shortest possible time. Because, precisely what we do not have is a lot of time to lose.
We will do it ? I doubt it. We are too selfish.