A significant portion of the Earth’s surface, about 70%, is covered by water, with 97.6% of it belonging to the seas and oceans. This vast expanse of water has played a crucial role throughout human history, shaping the way societies have developed. Our reliance on the sea for various resources and its role in transportation and energy production has only grown over time. In recent years, the potential of the ocean as a source of renewable energy has become a focal point, particularly with the development of tidal energy.
Tidal energy is a form of renewable energy that harnesses the natural movement of tides, driven by the gravitational pull of the sun and the moon. It generates clean electricity through the use of advanced technology. One of its key advantages is its predictability, as tidal cycles are well understood, unlike other renewable sources such as wind or solar power, which are influenced by unpredictable weather patterns. The ability to accurately forecast tidal cycles makes it easier to integrate tidal energy into the energy grid.
Tidal energy works by taking advantage of the movement of water due to gravitational forces. High and low tides, familiar to anyone with basic knowledge of marine environments, create a natural fluctuation in water levels. Tidal energy facilities harness this movement to generate electricity.
One type of tidal facility is the tidal range installation, which operates similarly to hydroelectric plants. These facilities use retaining walls or dams to trap water when the tide is high. As the tide recedes, the stored water flows through turbines, generating electricity. However, these installations require specific geographical conditions and can have a significant environmental impact, particularly when built in estuaries or bays.
Another approach involves tidal stream generators, which are turbines anchored to the seabed. These turbines resemble wind turbines but are designed to harness the energy of water currents instead of wind. This method is less invasive to the environment and has lower costs, making it an increasingly popular choice. As the currents move through the turbines, they generate the mechanical energy needed to produce electricity, which is then transported to consumers through the electrical grid.
There is also a theoretical technology known as dynamic tidal power (DTP), which seeks to capture both the kinetic and potential energy generated by tidal currents. This method involves constructing large dams that extend far into the sea, creating a difference in sea level on either side. Turbines are then used to capture the water flow from one side to the other, generating energy. While still in the experimental stage, this concept holds promise for future developments in tidal energy.
Tidal energy offers several benefits. It is a renewable and reliable source of power, as tidal cycles are consistent and predictable. The energy generated is dense, meaning that a single installation can produce significant amounts of electricity compared to other renewable sources. Maintenance costs are relatively low, and the lifespan of these facilities is long, with estimates ranging from 75 to 100 years. Additionally, tidal range facilities can also serve as flood defences, providing dual benefits.
Various renewable energy technologies are being explored to harness the power of the sea. These include tidal current energy, which captures the kinetic energy of ocean currents, wave energy, which utilises the movement of waves to generate electricity, and ocean thermal energy, which extracts power from the temperature difference between surface waters and the seabed. Tidal energy, in particular, stands out for its predictability and potential for long-term sustainable energy production.
The seas have always influenced our environment, and tidal energy presents a valuable opportunity to tap into their power sustainably. As research and technology continue to evolve, the ocean could become an even more essential source of clean, renewable energy for the future.
