Blue energy: The renewables underdog
The sea offers many options for energy generation, explains Gesine Meissner.
Unlike wind and solar power, generating energy from the ocean is reliable and predictable. Waves are available all year round, the tides are fixed and the salt content of the sea is constant. From a technical perspective, blue energy can be broken down into various areas depending on the method and the precise source of energy generation: wave, tide, thermal and osmotic energy.
The EU has set a goal of covering 27 per cent of its total energy requirement with renewable energies by 2030. Energy from the sea can also be supplemented by, for example, wind and solar power; with less sun, the wind and the waves are stronger.
In a communication published in 2014, the Commission highlighted the significant potential of energy from the sea not only in terms of achieving climate objectives but also in terms of jobs and exporting energy.
Almost all major technology developers have their headquarters in Europe, while the Commission is actively promoting this approach, including through the FORESEA project, which is being funded to the tune of €11m.
Those being supported include Corpower Ocean, a company in Stockholm. This uses wave energy based on the pump principles of the human heart and implements this with mini power stations in the form of buoys.
The use and development of wave energy through pumps can also be found in Scotland. There, Aquamarine Power is building systems based on the current model, ‘Oyster’, around 500 metres off the Scottish coast.
These systems are placed in water that is 10 metres deep and catch the waves using a vertical surface, then guide the energy from these waves to land to generate electricity through a converter and a seawater pipeline.
Tidal power stations also use the flow of the water. By setting up dams along coastlines and equipping them with underwater turbines, the tidal flow of water in and out can be used to generate energy. Another model is turbines on the seabed, like on the coast of Cornwall, or cables fixed to these.
Turbines can also be used to exploiting temperature differences of 20 degrees or more in the sea, such as are found between the surface of the water and deeper layers of the ocean.
By evaporating warm water on the surface of the ocean and channelling the gases into colder layers under pressure using a turbine, the gas can be cooled, turned back to a liquid and pumped back to the surface. This results in a cycle that generates energy.
Blue energy still faces challenges. The technology is currently expensive, as most of it is still in the test phase and funding is difficult to obtain.
Transmission networks have not been sufficiently expanded, while the environmental impacts have yet to be fully researched. Both are factors preventing the sector from developing profitable models.
Further investment is needed for researching, developing and testing blue energy and its effects. Otherwise, the sector’s potential will remain unfulfilled. The European Union cannot afford this if it wants to take the achievement of the climate objectives seriously.
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