Pelamis Wave Energy Converter

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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.

Operation

The Pelamis machine consists of a series of semi-submerged cylindrical sections linked by hinged joints. As waves pass along the length of the machine, the sections move relative to one another. The wave-induced motion of the sections is resisted by hydraulic cylinders which pump high pressure oil through hydraulic motors via smoothing hydraulic 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 and linked to shore through a single seabed cable.

Principles

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.

Projects

Scotland

Pelamis Wave Power tested their first full-scale prototype at the European Marine Energy Centre in Orkney, Scotland between 2004 and 2007. The machine, which was rated at 750 kW, was the world's first offshore wave power machine to generate electricity into the grid system. In 2010, Pelamis Wave Power returned to EMEC to test the second generation Pelamis machine, the 'P2'. The machine is owned by the German utility company, E.ON, and was the UK's first commercial supply contract in the marine energy sector. In March 2010 Pelamis Wave Power announced a second order for a P2 machine, from ScottishPower Renewables, part of Iberdrola Renovables. This machine is due to be installed at EMEC, in summer 2011. The two utility companies have announced that they will work together to share and collaborate in testing of the P2 Pelamis technology.

Both E.ON and ScottishPower Renewables have announced plans to build larger projects using Pelamis machines in the waters off Orkney's west coast. Both companies won leases in 2010 from The Crown Estate, who own the seabed around the UK, for projects of up to 50MW. The 'Pentland Firth and Orkney Waters Leasing Round' was the world's first commercial scale wave and tidal energy leasing opportunity. Pelamis Wave Power were also awarded a lease in this round to independently develop a project of up to 50MW on the north coast of Scotland at Farr Point, Sutherland.

In December 2009, Pelamis Wave Power announced a joint venture with Swedish utility Vattenfall to develop a wave farm off the southwest coast of Shetland. The joint venture company, named Aegir Wave Power, is planning to install a 10MW farm using around 13 Pelamis machines and were awarded an Agreement for Lease from The Crown Estate in May 2011.

Portugal

Main article: Aguçadoura Wave Farm

1 of 3 Pelamis machines at the Aguçadoura Wave Farm

The Aguçadoura Wave Farm was the world's first wave farm. Located off the northwest coast of Portugal near Póvoa de Varzim the farm had an installed capacity of 2.25MW and used three Pelamis P1, first generation, machines. The project was funded by Portuguese utility Enersis, at the time were owned by Australian global investment company Babcock & Brown. The farm first generated electricity in July 2008 but was taken offline in November 2008 at the same time as Babcock & Brown encountered financial difficulties.

Worldwide

Pelamis Wave Power has also expressed an interest in installing Pelamis devices at the Wave hub development off the north coast of Cornwall, in England, and in the Pacific ocean off the coast of Tillamook, Oregon.

Etymology

Pelamis platurus is a yellow-bellied sea snake that lives in tropical and subtropical waters. It prefers shallow inshore waters.

In the media

The Aguçadoura Wave Farm was featured in the Yann Arthus-Bertrand documentary "Home".

Pelamis was featured in the 2008 television documentary "Man-Made: Aqua Power".

BBC's Bang Goes the Theory explored inside the Pelamis P2 in Episode 4 of Series 3.

It was featured on James May's Big Ideas.

Images

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  2 of 3 Pelamis machines in the harbour of Peniche, Portugal.

• 

  Pelamis prototype machine at EMEC.

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  The front of the Pelamis machine bursting through a wave at the Aguçadoura Wave Park

See also

• E.ON
• Siadar Wave Energy Project
• Ocean energy
• Wave farm
• Wave power

External links

• Pelamis Wave Power Ltd.
• Aegir Wave Power
• The European Marine Energy Test Centre
• The Power Technology website
• Pelamis Secures Wave Energy Order from E.on
• Pelamis at Aguçadoura video