What are the most promising ocean energy technologies and innovations?

Though the research in wave energy is not new as the first patent in wave energy was obtained in 1799, due to the high complexity of the ocean and its surface along with the lack of commercial interest in new renewable energy that presided over the time of the invention made this technology less matured than the other renewable energy. With the current maturity in solar and wind energy, wave energy is a costlier technology making it a less interesting solution among investors. Several studies proved that an island with decent wave potential and low energy requirements can use wave energy technology as it will be a cheaper option among all solar, wind, and diesel energy generators, provided the necessary supply chain.

One thing I found useful is that based on a report from Precedence Research, the global wave and tidal energy market size reached USD 500.2 million in 2022 and is estimated to hit around USD 1,211.56 million by 2032. This shows that the market trend is growing upwards. In my opinion, with the renewable and clean energy push from multiple countries there is no doubt that the technology will see more focus in the coming years.

Wave energy will be a promising solution in the renewable energy sector. With a global potential of 29,500 TWh/yr (theoretically), wave energy can be seen at its maximum between the latitude of 30 degrees and 60 degrees. To put it in simple terms, this energy is similar to 10 times of the whole Europe's annual electricity consumption. The western coast of the USA, Canada and the UK, Chile, the southern coast of Australia, and the coast near Japan are known for their wave energy potential. Hence, wave energy research can be seen predominantly from these countries.

Another type of wave energy convertor is Bulge Wave technology. In Bulge Wave technology, a rubber tube filled with water is anchored to the seabed and oriented towards incoming waves. Water enters through the stern, and as waves pass, pressure changes occur along the tube, forming a 'bulge.' This bulge, as it travels through the tube, accumulates energy that can be harnessed to power a conventional low-head turbine positioned at the bow. Subsequently, the water is released back into the sea, completing the energy capture cycle.

Venturing into the origins of wave energy unveils a fascinating journey that stretches back to the late 18th century. In 1799, French innovator Girard, alongside his son, secured the inaugural patent for wave energy technology, marking a pivotal moment in the exploration of harnessing the power of ocean waves. The subsequent timeline reveals significant milestones, such as the advent of the first artificial wave machine in 1910 by Busso Belasek and the development of the enduring oscillating water column by Bochaux Praceique during the same period.

Tidal energy is a form of renewable energy harnessed from the movement of tides. In India, the potential for tidal energy is significant, especially in regions like the Gulf of Kutch, the Gulf of Khambhat, and the Sundarbans. Despite this potential, tidal energy remains underdeveloped in India due to high initial costs, technological challenges, and the complex marine environment. As of now, India has no commercial tidal energy plants, though pilot projects have been proposed. The government is exploring ways to develop this resource, but progress is slow compared to other renewable energies like solar and wind. The focus remains on research and development to make tidal energy a viable part of India's energy mix.

The most promising ocean energy technologies include tidal energy, which harnesses the power of tidal currents, wave energy that captures the movement of surface waves, and ocean thermal energy conversion (OTEC), exploiting temperature differences between surface and deep water. Additionally, innovations in floating wind turbines and advancements in underwater turbines are showing potential for efficient and sustainable ocean-based energy generation.

Tidal energy, derived from the natural rise and fall of ocean tides, is a promising and predictable source of renewable energy. Two primary technologies harness this power: Tidal Stream Generators: Similar to underwater wind turbines, these devices capture energy from the flow of water caused by tidal currents. They are positioned in fast-flowing tidal areas and can generate electricity consistently due to the predictable nature of tides. Tidal Barrages: These large-scale structures are built across the entrance to a tidal basin. Water turbines within the barrage are driven by the movement of water as tides ebb and flow, generating electricity.

Tidal power represents a promising part of the renewable energy mix, offering a reliable and predictable way to generate electricity from the ocean's natural movements. There are different technologies for capturing tidal energy. The most common include: Tidal Dams: Dam-like structures built in estuaries or bays. They allow water to enter during high tide and release it back into the sea during low tide, generating electricity through turbines. Underwater Turbines: Similar to wind turbines, but submerged in areas with strong currents. They generate electricity directly from the kinetic energy of tidal currents. Tide Pressure Generators: Devices that capture energy generated by changes in water pressure caused by changing tide levels.

Ocean current energy is a renewable energy source generated by the kinetic energy of ocean currents. It offers a consistent and predictable energy supply, unlike other renewable sources. In India, ocean current energy is still in its nascent stage. The country's vast coastline, especially along the western coast, has significant potential for harnessing this energy. However, development is limited due to high costs, technological challenges, and environmental concerns. Research and pilot projects are being explored, but large-scale implementation is yet to take off. India's focus remains primarily on more established renewables like solar and wind energy.

Ocean current energy technology uses submerged turbines that work in a similar way to wind turbines, but are driven by the force of marine currents instead of wind. The energy generated by these turbines can be used to power desalination processes. One of the desalination methods that can benefit from this energy is reverse osmosis, which requires a significant amount of energy to force seawater through semipermeable membranes, removing salt and other impurities.

Harnessing ocean thermal energy to produce drinking water will be an issue at the heart of this technology. In OTECs, warm seawater from the surface is evaporated in a low-pressure chamber, creating water vapor that is then used to drive a turbine and generate electricity. After the steam passes through the turbine, it is condensed using cold water from the bottom of the ocean. This condensation process results in fresh water, which can be collected and used as drinking water - a very valuable commodity for arid coastal regions and islands that suffer from freshwater shortages.