Renewable Energy

Overview of Renewable Energy Sources in the Ocean

The oceans offer resources for many kinds of renewable energy, with its waves, tides, and currents being able to produce energy. It is currently an untapped, underdeveloped industry, but with further research and investment, the ocean has the potential to supply 350 Gigawatts of energy by 2050, enough to provide clean energy to coastal nations and islands around the world. 

Wave Energy

One energy resource is wave energy which harnesses the energy of waves and transforms it into electricity. The structure of this energy consists of a point absorber in the form of a floating buoy that absorbs energy through the water’s movement. This then propels the electric generator underwater, thus outputting electricity by continuously moving up and down. Another form of this structure is the linear absorber which works in a similar way, absorbing the waves energy and converting this into electricity.

Tidal Energy

Tidal energy is another form of ocean renewable energy that harnesses the energy of the rise and fall of tides. This sustainable approach involves strategically situating turbines within tidal streams, which are then coupled with specialized generators to seamlessly transform tidal power into electricity. Leveraging the inherent density of water, tidal energy surpasses wind energy in potency, offering a robust and reliably predictable source of power. Alternative methods such as barrages, intricate systems involving large dams equipped with turbines, also contribute to energy generation; however, they often carry substantial environmental implications. Similarly, tidal lagoons operate on a comparable principle, employing turbines within artificially constructed lagoons to harness the cyclic inflow and outflow of water.

Wind Energy

Offshore wind farms also have the potential to provide significant amounts of energy, with stronger and more consistent wind at sea rather than on land. The wind moves the blades around the rotors of the turbines, and the energy generated from this transfers through power cables to substations where it is converted to electricity, and eventually enters the power grid.

Ocean Thermal Energy

Ocean thermal energy conversion is the process of harnessing the thermal gradients between ocean waters, with a temperature difference of more than 20 degrees celsius or 36 degrees fahrenheit being able to spin the turbine, thus producing electricity. Ocean thermal energy works by utilizing the temperature difference between warm surface water and cold deep ocean water. Firstly, warm surface water is pumped through a device called an evaporator, where it heats up a working fluid until it turns into vapor. This vapor then drives a turbine connected to a generator, producing electricity. Afterward, the vaporized fluid is cooled down and condensed back into a liquid state in a condenser, which is cooled by the cold ocean water pumped from deeper in the ocean. This cycle can be repeated continuously to generate electricity. Additionally, in systems that use seawater as the working fluid, the condensed water can also be used to produce fresh water through desalination.

Potential for Energy Generation

Ocean renewables have the potential to revolutionize the energy industry, offering an opportunity to eliminate the need for greenhouse gasses. Once developed, it will enhance the predictability of energy, create new employment opportunities, contribute to the decarbonisation of the blue economy, and offer an endless supply of energy at a low cost for generations to come. The sector can create 680,000 new jobs and support coastal communities.

Advantages and Challenges

The ocean covers 70% of Earth’s surface, nearly 1.5 billion cubic kilometers of water. This enormous area has great potential for energy generation. Currently, only 0.3% of electricity is generated by oceanic energy, but by utilizing a combination of ocean renewable energies, a more sustainable sector can arise within the blue economy, providing clean energy to coastal regions and creating new employment opportunities.