Should tidal energy be a part of our green future?

Group 8


Tidal energy is an increasingly employed means of harvesting renewable energy, forecasted to grow ​15.8% annually between 2022 to 2027.  A popular form of tidal energy generation are tidal barrages.These are dam-like structures installed across a bay or estuary to form a tidal reservoir. The barrages have sluices that control the tidal flow to drive its two-way tidal power system and generate electricity.Although barrages are a predictable, reliable, and clean form of energy production, they pose a threat to aquatic ecosystems and local fishing communities. This begs the question: Should tidal barrages be a part of our green future?


On one hand, tidal barrages can produce clean and renewable energy. We hear about the climate changes daily. We all know that transitioning away from fossil fuels and non-renewable energy sources is needed to reach climate goals, such as the Paris agreement. Building more tidal barrages is a step in the right direction. Unlike wind, tidal waves are very foreseeable, as the differences in sea level happen twice a day, making tidal energy very predictable. It also has the potential to harvest more energy than wind because of the water’s greater density. A survey conducted by the UK Department for Business, Energy and Industrial Strategy in March 2021 showed that 74% of people support or strongly support the development of tidal energy. The theory of utilitarianism states that what brings more happiness to a greater number of people is the right decision to make. According to the survey and utilitarianism, building tidal barrages in the UK would be morally right. Building these barrages will give a lot of people access to renewable energy. Taking this into consideration it will bring a greater number of people clean and renewable energy than the number of people affected by the construction of the barrages. This gives us two good reasons for building the tidal barrages, supported by the theory of utilitarianism.

Furthermore, tidal barrages can help to mitigate the impact of storm surges on coastal flooding. Storm surge barriers such as tidal barrage can effectively protect harbours, minimise flooding, property damage, and prevent the loss of life in coastal areas during large storms. According to Kant’s deontological ethics, we have the capacity for rationality. Hence, employing tidal barrages as a storm surge barrier to protect the life of humans living on the coast is a universal law without contradiction. It is our moral duty to seek an outcome that is equal for everyone.

We can further validate businesses implementing such barrages using virtue ethics. Sustainable development is a priority in the political and social arenas, as well as in business. So, due to social and political pressure, businesses are motivated to find innovative ways to pursue environmental quality and social equity. Both innovation and humanitarianism are seen as virtuous and admired traits. Moreover, such businesses are also demanded to display honesty, competency, fairness, and transparency – all of which are also seen as virtuous. Hence, businesses that implement tidal barrages can be seen as virtuous agents due to their moral foundation and admirable actions.


On the other hand, there are several disadvantages to tidal barrages preventing them from increasing in popularity.

Firstly, it disrupts marine ecosystems. Tidal barrages are most efficient when the variation in tides is greatest, so they are usually constructed at bays and river mouths, where ecosystems flourish. Building these barrages alters the natural flow of the water, which causes sediment damming and changes the water’s turbidity and salinity. Turbidity determines how much sunlight is scattered by the particulate matter in the water. If bays are blocked off by barrages, sediment have nowhere to flow, increasing turbidity which in turn reduces the light reaching kelp forests and other algae. This process leads to a vicious cycle, as kelp forests and algae are vital members in oxygenating the water and keeping marine life healthy. Secondly, estuaries are often the gateway for migratory fish such as salmon, whose spawning grounds lie upstream. The construction of a barrage not only disrupts their migration patterns but also causes fatal injuries when fish and other aquatic animals pass through the turbine blades. Hence, the environmental harm caused by constructing tidal barrages conflicts with the green ethics theory.

Having this environmental awareness poses a virtue ethics argument as both flora and fauna in these ecosystems are catastrophically affected. This may lead to the loss of habitat and species as well as the degradation of the environment, both of which are not virtuous.

Another stakeholder that must be considered is the fishing communities that dwell along these river banks, which are directly affected by the lack of inbound fish. In addition to this, these communities often use estuaries as their only gateway to the ocean to carry out their work. A Kantian argument can be made here as the construction of a barrage takes away the livelihoods of usually low-income communities, such as developing nations like Sri Lanka and India, that show increasing interest in projects like this.

Furthermore, the majority of the population takes pleasure in unspoilt scenery, and the implementation of such intrusive barrages opposes the theory of utilitarianism.

The Rance Tidal Power Station. World’s largest tidal barrage, located in North-West of France.

In consideration of the economic impact, the cost per kilowatt of energy generated by this method is substantially higher than most other forms of energy generation. Prices of fossil fuels are generally increasing, even more significantly in 2022 with the Russia-Ukraine conflict. This means that the construction cost of tidal barrages is becoming more financially viable.

Initial Decision:

We are against tidal barrages.

8 thoughts on “Should tidal energy be a part of our green future?

  1. Good arguments for and against introducing tidal power stations. To expand on Olamides’s point, the Utilitarianism argument Against tidal power should be developed by being backed up by evidence or further explanation.
    Fossil fuels are harming the environment, and introducing tidal power stations helps mitigate this but with further consequences as you mention. That being said, I think its worth directly comparing the environmental damage the solution creates to the damage the problem causes.
    Overall, great read, and definitely eye opening points made.

  2. This is a topic I had never thought of before, the original intention of using tidal energy was to generate clean and renewable energy to reduce the environmental harm caused by human activity. However, as the article states, there is a significant risk that the process of harnessing tidal energy could be harmful to the environment, which conflicts with the original purpose of harnessing tidal energy and defeats some of its purpose. Therefore I do support the arguments against the use of tidal energy in the article and I think that there is a better future for the use of wind energy.

  3. Very nice topic and an eye-opener. Previously I had considered the pros of tidal energy to greatly overshadow the cons. It turns out the technology that is meant to protect the environment could potentially harm it in other ways. In order to implement tidal power generation without damaging the ecosystem, some form of preventative measures have to be taken.

  4. A very enjoyable read, it definitely highlighted a lot of aspects to tidal energy that i was not previously aware of. The arguments on both sides have been very well stated, with good reasoning being offered for both. When looking at Kant’s deontological ethics for tidal barrages, was there any quantitively data on the amount of human life lost in coastal areas, to give an idea of the potential life saving benefit that would be seen post installation of these barrages, and whether or not bays and estuaries are the coastal areas that are most affected by storm damage? Another aspect i feel has been over looked is in the Kantian paragraph against the barrages is that the construction of the barrages could bring more income to these areas through the labour required to build, maintain and run the barrages. On the whole though, it this raises some really interesting points, and i am in agreement with your position of against the construction of these.

  5. This is a very well balanced argument and if I had to choose, I would be against too but that is mainly because the technology for it isn’t mature enough. Also, I wonder if the turbines can be manufactured in a way that allows fish to cross the barrages injury free.

  6. Feedback
    1. Clarity of problem/dilemma
    Good opening paragraph that clearly stated the issue.

    2. Use of ethical theories in the For Case
    Good, strong reasoning. Not much more I can say to improve it really. Have a look to see if Green Ethics provides support.

    3. Use of Ethical theories in the Against case
    Again, not too much for me to say. A good use of theories to support the opposing argument.

    4. Advice on Assignment Two
    a. Identifying stakeholders
    b. Courses of action
    There’s probably a win-win course of action here, some way to mitigate the environmental impact but still harvest the reliable tidal energy.
    With stakeholders, you’ve identified the environment, which is a nice example of a passive stakeholder.

    5. Personal remarks
    Overall, a very interesting topic, with a good balance of viewpoints. I wonder if the cost of tidal power is a consequence of it being at a less mature stage than wind or solar?

  7. – This article has been very eye opening. The range of facts that are included gives the reader context that is related to the dilema. There are very good points that were relevant for both sides of the argument, making good use of of the ethical theories such as Virtue Ethics and Utilitarianism. By considering the many factors that influence both the ‘For’ and ‘Against’ sides of the argument, you’ve created a well written argument thats interesting

  8. This was a great read and great arguments were made after reading both arguments I am still undecided. I am slightly confused concerning a few things; first, the last paragraph seems like an argument for tidal energy but it is in the against section. the second is there are no quantitative data to say that the majority of the population prefers unspoilt scenery. Also, does the population refer solely to the indigenes? if so the argument neglects the fact that tidal barrages like dams could become a tourist attraction.

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