The world is facing a climate crisis, and we need to find ways to reduce our dependence on fossil fuels and greenhouse gas emissions. Renewable energy sources, such as solar and wind, are becoming more popular and accessible, but they have some limitations. They depend on the weather conditions, and they are not always available when we need them. Is there another option that can provide clean, reliable, and sustainable energy?
One possible solution is tidal power. Tidal power is the energy generated by the movement of water caused by the gravitational pull of the moon and the sun. Unlike solar and wind, tidal power is predictable and constant. Every day, there are two high tides and two low tides that can be used to generate electricity. Tidal power has the potential to meet a significant portion of our energy demand, especially in coastal areas.
How Tidal Power Works
There are different technologies that can harness tidal power, but they all work on the same principle: using turbines to convert the kinetic energy of water into electrical energy. The turbines can be placed on the seabed, in estuaries, or in artificial structures, such as barrages or lagoons.
The most common type of tidal power plant is the tidal stream plant. This involves installing underwater turbines in areas where there is a strong flow of water, such as narrow channels or straits. The turbines rotate as the water passes through them, generating electricity that can be transmitted to the shore through cables.
Another type of tidal power plant is the tidal barrage plant. This involves building a dam across an estuary or a bay, creating a reservoir of water. The dam has sluice gates that allow water to flow in and out during the tide cycle. The water passes through turbines that are located in the dam, generating electricity.
A third type of tidal power plant is the tidal lagoon plant. This involves creating a circular wall around a coastal area, enclosing a body of water. The wall has turbines that allow water to flow in and out during the tide cycle, generating electricity.
The Benefits of Tidal Power
Tidal power has many advantages over other renewable energy sources. Some of the benefits are:
- Tidal power is renewable and sustainable. It does not use any fuel, and it does not produce any pollution or greenhouse gas emissions.
- Tidal power is reliable and predictable. It is not affected by weather conditions, and it can provide a steady supply of electricity throughout the day.
- Tidal power is efficient and scalable. It has a high energy density, meaning that it can generate more power per unit area than other renewable energy sources. It can also be scaled up or down according to the demand and availability of suitable sites.
- Tidal power is compatible and complementary. It can be integrated with other renewable energy sources, such as solar and wind, to create a balanced and diversified energy mix. It can also be used for other purposes, such as desalination, irrigation, or recreation.
The Challenges of Tidal Power
Tidal power also has some challenges and drawbacks that need to be addressed before it can become a mainstream energy source. Some of the challenges are:
- Tidal power is expensive and complex. It requires high initial investment and maintenance costs, as well as advanced engineering and technology. It also faces regulatory and legal hurdles, such as environmental impact assessments and permits.
- Tidal power is limited and variable. It depends on the geographical features and tidal patterns of each location, which may not match the demand and supply of electricity. It also varies according to the lunar cycle and seasonal changes.
- Tidal power is disruptive and risky. It may have negative effects on the marine ecosystem and biodiversity, such as altering the natural flow of water, sedimentation, noise pollution, collision with marine animals, or habitat loss. It may also pose hazards to navigation, fishing, tourism, or coastal protection.
The Impact of Tidal Power on Marine Life
One of the main concerns about tidal power is its impact on marine life¹²³⁴⁵. Tidal power plants may affect the marine environment in different ways depending on their design, location, size, operation, and monitoring.
Some of the possible impacts are:
- Physical injury or mortality: Tidal turbines with their rotating blades may cause injury or death to marine animals that come into contact with them²³. This may affect fish populations, marine mammals (such as seals or dolphins), seabirds (such as gulls or terns), or endangered species (such as sea turtles or sharks).
- Behavioural changes: Tidal turbines may also affect marine animals indirectly by altering their behaviour²⁴. For example, noise from the rotation of the turbines may disturb or deter fish or marine mammals from their natural habitats, migration routes, feeding grounds, or breeding sites. This may reduce their survival, reproduction, or diversity.
- Habitat modification: Tidal turbines may also affect the physical and chemical properties of the water and the seabed²⁵. For example, they may change the flow of water, the distribution of sediment, the temperature, salinity, or oxygen levels of the water, or the availability of nutrients or light. This may affect the growth, diversity, or distribution of marine plants (such as seaweed or seagrass) or animals (such as crabs, worms, or mussels) that live on or near the seabed.
The impact of tidal power on marine life is not fully understood and may vary depending on the local conditions and species involved. Therefore, it is important to conduct thorough environmental assessments and monitoring before, during, and after the installation and operation of tidal power plants. It is also important to apply mitigation measures, such as selecting suitable sites, designing turbines to minimize harm, using acoustic deterrents or screens to prevent collisions, or restoring habitats after decommissioning.
The Future of Tidal Power
Tidal power is still in its early stages of development, but it has shown promising results in some countries, such as France, Canada, China, South Korea, UK etc¹²³. There are many ongoing research projects and pilot plants that aim to improve the efficiency, affordability, safety, and sustainability of tidal power⁴⁵. Some examples are:
- TPGen24: A project that aims to create a 24/7 base load electricity generation system using tidal power.
- ScotRenewables Tidal Turbine: A project that aims to develop and test a floating tidal turbine that can be easily deployed and retrieved.
- Tidal Lagoon Swansea Bay: A project that aims to build the world’s first tidal lagoon power plant in Wales.
Tidal power has the potential to become a realistic alternative energy source, but it needs more research, innovation, and support to overcome its challenges and reach its full potential. Tidal power can be a valuable addition to our renewable energy portfolio, and help us achieve a low-carbon and green future.
(1) Tidal energy – BBC Bitesize. https://www.bbc.co.uk/bitesize/topics/znrwdp3/articles/z3hwkty.
(2) Waves and tides have bigger impact on marine life than human activity. https://phys.org/news/2020-03-tides-bigger-impact-marine-life.html.
(3) Profiling the top tidal power pros and cons – NS Energy. https://www.nsenergybusiness.com/features/newsmajor-tidal-power-pros-and-cons-5766117/.
(4) Tidal Power – Renewable Energy from the Ocean’s Movement. http://large.stanford.edu/courses/2021/ph240/wilson2/.
(5) How do tides and turbines affect sealife? Fundy study hopes to find out. https://www.cbc.ca/news/canada/nova-scotia/bay-of-fundy-tidal-power-development-force-1.6412184.
(6) Getty Images. https://www.gettyimages.com/detail/photo/tide-power-station-royalty-free-image/881824352.