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Cost of Using Tides for Energy: What Are The Pros and Cons?

The tides have been a source of fascination and wonder for humanity since we first laid eyes upon the ocean. And of course, nowadays they are also fantastic sources of power! Although tidal power generation is, relatively speaking, still in its infancy. It’s quite likely that it will play a more and more important role in the generation of our electricity for years and decades to come.

What is Tidal Energy?

What is Tidal Energy?

Put very simply, tidal power refers to the way that we use the ocean in order to generate electrical energy. It’s a green source of energy, which can be used in many places around the world that have a coastline. Unlike fossil fuel technology, tidal power doesn’t require us to burn anything – which of course means that deadly gasses don’t enter the atmosphere as a result of tidal power.

There are already quite a few tidal power stations in use around the world. The absolute largest tidal power plant on earth is in South Korea – the Sihwa Lake tidal power plant, which can generate up to 254 megawatts of electricity! So as you can see, tidal power can actually provide a colossal amount of energy – which of course is no surprise when you consider how much energy there must be in the movement of water on the ocean!

The sheer amount of energy available in the ocean combined with the fact that nothing needs to be burnt to generate electricity from tidal power of course means that, compared to fossil fuels, tidal power is a far cleaner and more sustainable way of generating electricity.

How Can We Use Tidal Energy?

How Can We Use Tidal Energy?

Of course nothing comes for free, and while tidal power may be an absolutely fantastic source of energy, it’s useless to us unless we find a way to harness it. Of course, there are a few different technologies that humanity has been working on over the past century that enable us to use the enormous power of the tides to generate electricity.

The most well-known ways of generating electricity using tidal power are tidal stream generators and tidal barrages. There are actually some other technologies that could be used to generate electricity using the tides – however, at the moment these are more theoretical propositions than practical solutions. This isn’t to say that these technologies have no merit – but to simply state that they’re not actually in use yet.

A tidal stream generator essentially works very much like a wind turbine, except that instead of using wind to move the turbine it instead uses moving currents of water. This gives tidal stream generators their other name, tidal turbines.

Tidal energy

However compared to a wind turbine, a tidal stream generator is generally far more efficient, being in the region of 10 times more efficient at converting water flow into electrical energy than a wind turbine is when using air to move the turbine. Tidal stream generators are great ways of harvesting energy from the ocean.

A tidal barrage is much the same as a tidal stream generator in many ways. Just like a tidal stream generator, a tidal barrage uses the motion of flowing water in order to move a turbine to generate electricity. The main difference between a tidal barrage and a tidal stream generator is really in terms of scale. Whereas a tidal stream generator could just be a single unit that stands in a body of water, a tidal barrage is instead much larger.

In fact, they can be similar in scale to dams – of course with the one key difference being that a tidal barrage is intended to allow water to flow through. The intent of the barrage isn’t to stop the water, but to harness the colossal amount of energy contained within it in order to move an electricity-generating turbine.

Are There Any Environmental Concerns?

Are There Any Environmental Concerns?

Although tidal power is, compared to fossil fuels, a much cleaner form of energy generation, that doesn’t mean that there are absolutely zero environmental concerns.

One of the main things that worry scientists is whether tidal power has too much of a negative effect on marine life. This essentially is because it’s extremely easy for sea life to be killed by the rotating turbine blades. It’s possible of course to switch off some tidal power turbines when marine animals approach – however, due to the sheer amount of living creatures in open water bodies, this can often have the effect of a colossal loss of energy output, as the turbine must be disabled extremely often in these circumstances.

It’s estimated that even with a turbine that’s designed to minimize casualties of marine life, fish mortality per pass approaches 15%. This of course is far from Ideal and can really reduce the places where it’s viable to use tidal power. After all, fish can be a vital part of both the economy and the ecosystem of many places – therefore, it’s imperative that we take as many measures as we possibly can in order to protect them!

Another concern regarding tidal energy is acoustics. Marine life can be extremely sensitive to sound, and in fact, many aquatic animals rely on sound for communication and navigation. It is thought that the sound of tidal turbines can have a negative effect on local marine life. Certain animals in the ocean absolutely rely on sound to survive, for example in the use of echolocation. There are also potential concerns that active turbines can also generate electromagnetic fields which could also be harmful to marine life.

A tidal barrage by its very nature will inhibit and restrict the flow of water somewhat. Although they are of course designed to allow water to pass through, it’s inevitable that much of the energy that the water had will be sapped to generate electricity, meaning reduced flow. And of course, tidal barrages can be disruptive to humans too – for example, they can make it difficult for shipping!

Corrosion is always going to be an issue when it comes to tidal power generation. This is because the energy generating components will inevitably be immersed entirely in saltwater, which is extremely corrosive to many metals. Also, these moving parts have to be lubricated – and this lubrication can leak and be a danger to marine life.

And of course, it’s important not to forget that at the moment tidal power is extremely expensive to harness. No matter which method of harnessing tidal power we currently use, the fact remains that it is inescapably expensive to set up one of these power stations. This of course doesn’t mean the tidal power isn’t viable – however, it does mean that the sheer cost may make it at present unworkable in certain parts of the world.

Now, of course, none of this means that tidal power is useless to us, or that it’s not worth developing. However, it is important to have a realistic understanding of not just the strengths, but the weaknesses of any new green energy technology! Compared to many other ways of generating electricity, tidal power is still relatively young. It’s therefore extremely likely that not only will methods of using tidal power improve, but also that we will be able to use tidal power at reduced cost in the future.


Hopefully, this article has helped you learn a little more about the uses and potential challenges of tidal energy!

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