Articles

Proquest provides a method to view scholarly articles and research papers. This article describes how tidal energy is more or less a constant resource, differentiating it from different sun-derived energies such as wind and solar.

As stated in Proquest, tidal energy is on the rise as a new source of energy in European waters, Many innovations are getting close to having a life-size design and being built. "Basic, shallow water tidal theory is reviewed and it is shown that carefully sized tidal stream installation in the Clyde, Tees, Humber, Severn, Menai Straits and the Mersey" could get use out of the tidal flow and give us a constant supply of electricity.

The National Science Foundation, a reputable government site, has conducted studies on designing tidal and wave systems.

In the building of the of the propeller, the researchers had to work around water resistance as opposed to wind resistance in wind energy. The researchers changed the propeller orientation from horizontal to vertical, allowing direct interaction with the cyclic, up and down motion of wave energy. They also developed individual control systems for each propeller blade, allowing sophisticated manipulations that maximize (or minimize, in the case of storms) interaction with wave energy.

The real-world application and efficiency of tidal and wave energy is adressed in this article by Science Direct.

Although it is likely that every device concept will have its own specific impacts on the flow environment, there will be generic impacts resulting from energy extraction from the water column and the resulting flow distortion. These flow distortions can affect passing sea life and disrupt coral and the sea floor, depending on the location of the device.

The problem is quite distinct from wind extraction: tidal devices will typically be extracting an appreciable proportion of the kinetic energy flux and will be located relatively close to the upper boundary of the flow environment, the free surface between the water and the air, while wind devices are located near the bottom of a very deep atmospheric layer. These distinct energy sources are both renewable, yet the differences might be part of the reason that wave and tidal energy isn't being used as much. The propellers for wind power can be weather proofed in a similar way to weatherproofing a house. On the other hand, weatherproofing an underwater propeller presents other challenges, protecting against the salt and any floating debris.

The difficulty of building devices that can weather the elements are discussed in length by the NSF here.

The engineers were presented with the challenges of salt water and the roughness of waves. The same constant motion of waves that provides the energy is also continuously battering the hardware that is capturing it. So the engineering challenge is making that hardware strong and simple.

The actual energy harnessing process as von Jouanne explains, is "a float heaving up and down with the waves. Underneath the float is a magnet assembly, and as that magnet assembly heaves up and down, it creates a changing magnetic field. The coils in the spar experience that changing magnetic field and that induces voltage, and creates electricity."

Companies

This British Nonprofit is working to create a sustainable energy future through the use of tidal and wave energy.

OpenHydro is a company that works to manufacture renewable tidal turbines. They strive to, "Extract energy from the oceans in an economically viable and environmentally sensitive manner".

The functionality and survivability of equipment in an underwater environment demands simplicity and robustness. The Open-Centre Turbine meets these demands, with its slow-moving rotor and lubricant-free operation. It has a number of design features intended to avoid any impact on marine life. The large open center provides a safe passage for marine life and the turbine's clean hydrodynamic lines ensure that fish will not become entangled. The blade tips are retained within the outer housing which clearly defines the moving component and the turbine is designed to generate energy at a slow rotational speed. The design avoids the use of oils, greases or other lubricating fluids that could present a pollution risk. Tests have also confirmed that the unit produces very low levels of mechanical noise. This technology provides a viable option as an energy source with the dangers removed using these safety techniques.

Current Events

1.6M funding provision for Wales' first full-scale tidal energy generator View Page

More wave and tidal sites available, and three more developers given green light View Page