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Abstract
A variety of technologies have already been proposed to capture energy from ocean waves, but this one requires a minimum of
material, is cheap and robust. Rather than looking at the up and down movements of waves, the proposed method lets the
circular water currents beneath the waves directly drive rotors..
Due to economic social cohesion, the European Union is promoting to improve the production of electrical energy from
renewable energy sources. Sea waves have associated a form of renewable energy which can be captured by using a hydro
mechanical device that in turn drives an electrical generator to produce electrical energy. After a brief description of wave
formation and quantifying the power across each meter of wave front associated to the wave, the paper describes several
devices used presently to extract mechanical energy from the waves and their advantages and disadvantages are presented as
conclusions. In particular, the modern Pelamis system is described in some detail. Wave energy market is also discussed.

Introduction
To protect the environment for future generations it is vital
that we move rapidly to a more sustainable lifestyle,
reducing carbon emissions of greenhouse gases and
consumption of limited resources. Offshore wave energy
has the potential to be one of the most environmentally
benign forms of electricity generation with a minimal
visual impact from the shore.
Wave energy is essentially stored, concentrated wind
energy, the waves being created by the progressive
transfer of energy from the wind as it blows over the
surface of the water. Wave energy could play a major part
in the world’s efforts to combat climate change,
potentially displacing 1 – 2 billion tonnes of CO2 per
annum from conventional fossil fuel generating sources.
Such installations would also provide many employment
opportunities in construction, operations and
maintenance.The Pelamis Wave Energy Converter is a
technology that uses the motion of ocean surface waves to
create electricity. The machine is made up of connected
sections which flex and bend as waves pass; it is this
motion which is used to generate electricity. Developed by
the Scottish company Pelamis Wave Power (formerly
Ocean Power Delivery), the Pelamis became the world’s
first wave machine to generate electricity into the grid
from offshore wave energy, when it was connected to the
UK grid in 2004. Pelamis Wave Power have since gone to
build and test four additional Pelamis machines. Three,
first generation P1 machines which were tested in a farm
off the coast of Portugal in 2009 and the first of a second
generation of machines, the P2 started tests off Orkney in
2010 .
The Pelamis is an attenuating wave energy converter
designed with survivability at the fore. The Pelamis's long
thin shape means it is almost invisible to hydrodynamic
forces, namely inertia, drag, and slamming, which in large
waves give rise to large loads. Its novel joint configuration
is used to induce a tunable cross-coupled resonant
response. Control of the restraint applied to the joints
allows this resonant response to be ‘turned-up’ in small
seas where capture efficiency must be maximised or
‘turned-down’ to limit loads and motions in survival
conditions.
It is named for a shallow dwelling sea snake and appears
just as serpentine at a length of 140 meters. It is the latest
innovation to tap nature’s power for our own. Pelamis is
the world’s first commercial wave power project set up off
the Portuguese coast. The Scottish engineering company,
Pelamis Wave Power Limited is the brains behind the
devices, technically called the Pelamis Wave Energy
Converters (PWEC).
The idea is simple in itself…the machine uses the motion
of the waves on the ocean surface to create power. It is a
series of semi submerged cylindrical sections linked by
hinged joints. The motion of these sections due to the
waves in turn churns the hydraulic rams which pump high
pressure oil through hydraulic motors. 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 sea bed. Several devices can be
connected together and linked to shore through a single
seabed cable.

Each Pelamis machine measures 120m long by 3.5m wide
(about the size of four train carriages) and weighs 750 tons
fully ballasted. The Pelamis Wave Energy Converter is a
semi-submerged, articulated structure composed of cylindrical
sections linked by hinged joints. The wave-induced motion of
these joints is resisted by hydraulic rams, which pump high-
pressure fluid 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 sea bed. Several
devices can be connected together and linked to shore through
a single seabed cab

Advantages
Pelamis offers technological, economic and environmental
advantages including: Current production machines are 180m
long and 4m in diameter with 4 power conversion modules per
machine. Each machine is rated at 750kW. The energy
produced by Pelamis is dependent upon the conditions of the
installation site. Depending on the wave resource, machines
will on average produce 25-40% of the full rated output over
the course of a year. Each machine can provide sufficient
power to meet the annual electricity demand of approximately
500 homes.

Electrical Power Research Institute-Public/private project
part funded by DOE, NREL and individual states-Project:
five state wave energy sites in Maine, Oregon,
Washington, Hawaii, Massachusetts + city of San
Francisco-Pelamis selected by EPRI as system currently
recommended for deployment.-Target installation 2007-
Funding for ocean energy approved in recent Energy bill
Pelamis
Conclusion
This technology might create additional markets for rubber,
plastic, aluminium, metal frames, cables, subsea connectors,
electromagnetic equipment, power inverters.
Let’s stop global warming!
References
1.http://en.wikipediawiki/Pelamis_Wave_Energy_Conver
ter
2. http://pelamiswave
3.http://renewableenergyworldrea/news/article/200
4/03/p
elamis-wave-energy-converter-is-launched-10639
4.http://changingideasPelamis-Wave-Energy-
Converter/Electricity.html
5.http://theirearthindex.php/news/pelamis-wave-power-
pelamis-wave-energy-converter
6.http://bionomicfuelis-the-pelamis-wave-energy-
converter-at-the-forefront-of-wave-energy/