Pelamis

It's almost compulsory to begin with the probably most known solution: the Pelamis "worm"

Technology:

• Wave damper
• 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. (100-350bar)
• 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.
• Current production machines are 180m long and 3.5m in diameter with 4 power conversion modules per machine. 700Tm
• Each machine is rated at 3x2x125= 750kW.
• Depending on the wave resource, machines will on average produce 25-40% of the full rated output over the course of a year.=> 2,7GWh
• The machine is held in position by a mooring system, comprising of a combination of floats and weights which prevent the mooring cables becoming taut. It maintains enough restraint to keep the Pelamis positioned but allows the machine to swing head on to oncoming waves.
• The Pelamis is designed to be moored in waters approximately 50-70m in depth where the high energy levels found in deep swell waves can be accessed.

Advantages:

• Floating device: easy to install, transport, maintain etc.
• Able to withstand adverse maritime conditions due to its hydrodynamic profile

Disadvantages:

• How much of the available energy is it able to capture?
• Joints between sections in contact with sea water
• Many moving parts: hydraulic cylinders, electrical motors...

Cost:

• Unknown
• £4.8m of funding for the P2 version
• The Aguçadoura wave energy project in Portugal is supported by a specific feed-in tariff currently equivalent to approximately €0.23/kWh.

Other info:

• First prototype installed at EMEC in 2004
• Patents: US6476511, AU754950, ZA20012008, EP1115976B;
• Projects:

1. Aguçadoura: 2.25MW (3x750kW) in Portugal, commissioned
2. E.ON at EMEC: 750kW P2 prototype
3. Orcadian Wave Farm: 3MW (4 x 750kW) in project near Orkney, Scotland
4. Aegir: 20MW (26 x 750kW) in development near Shetland, Scotland

Links:

Official Website

http://www.pelamiswave.com/

Videos:

http://www.youtube.com/watch?v=JYzocwUfpNg

http://www.youtube.com/watch?v=F0mzrbfzUpM&NR=1