Portugal has became the first nation to
fully tap into the power of the sea with construction of the first ever
commercial wave farm.
Located off the coast of Northern
Portugal at Aguçadoura, the wave farm is
estimated to generate enough electricity for up to 2,000 homes.
The wave farm is due to open for production of electricity by the end of
2007 and has been designed by Scottish company Ocean Power Delivery Ltd.
The 'Pelamis' (the Latin term for Sea Snake) is a semi-submerged,
articulated structure composed of four cylindrical sections linked by
hinged joints. They are then moored to the Ocean bed eight kilometres
off shore, pointing into the direction of the waves.
The wave-induced motion of these joints is resisted by hydraulic
rams, which pump high-pressure oil through hydraulic motors via
smoothing accumulators. The hydraulic motors drive electrical generators
to produce electricity.
Power from all the joints is fed down a single umbilical cable to a
junction on the seabed. Several devices can be connected together and
linked to shore through single seabed cable. A novel joint configuration
is used to induce a tuneable, cross-coupled resonant response, which
greatly increases power capture in small seas.
Tidal energy is a form of hydro power, which exploits the natural sea
currents to generate electricity. There are several different methods of
collecting energy from the Earth's oceans and seas.
One involves submerging turbines which with the natural tide slowly
rotate, this energy is converted in the turbine generator into
The second utilises semi-submerged cylindrical
structures, named Pelamis fixed together by hinged joints. These joints
which act as a pumping system, by pushing high pressure oil
through a series of hydraulic motors, which in turn drive the electrical
generators to produce electricity.