Tidal current electricity is clean, renewable, reliable and predictable.

Tidal Energy and Wave Energy

There is often confusion regarding the different types of tidal power, and indeed between tidal current power and wave power.  To summarise:

• Wave Energy Converters harness the vertical motion of waves
• Tidal Lagoons and Tidal Barrages block-in the potential energy of water at high tide, before releasing it through flood gates at low tide to harvest the energy.  Tidal Barrages, such as the proposed Severn Barrage in particular, are known to have adverse environmental effects.
• Tidal Current technology extracts energy from the high tide bulge created by the gravitational pull of the Moon and Sun moving horizontally around the Earth’s surface.  Unless taken to extremes, it does not require blocking of any waterways, and hence does not have the adverse environmental effects associated with Tidal Barrages.

Sea water, which is 832 times denser than air, gives a 5 knot ocean current more kinetic energy than a 350 km/h wind; therefore ocean currents have a very high energy density. Hence a smaller device is required to harness tidal current energy than to harness wind energy.

Tidal current energy takes the kinetic energy available in currents and converts it into renewable electricity. As oceans cover over 70% of Earth’s surface, ocean energy (including wave power, tidal current power and ocean thermal energy conversion) represents a vast source of energy, estimated at between 2,000 and 4,000 TWh per year, enough energy to continuously light between 2 and 4 billion 11W low-energy light bulbs.

Both the U.S. and the U.K., for example, have enough ocean power potential to meet around 15% of their total power needs.

For tidal current energy, there is an estimated 50,000MW or approximately 180TWh per year of economically exploitable resource available worldwide.

Governments have recognized the immense potential of ocean energy and
 have begun significant incentive programmes to harness it. Marine energy is
 currently the technology receiving the highest number of renewable obligation
 certificates (ROC) per MWh in the UK market, with 3 ROCs confirmed for tidal current energy.