Power from the waves

Global ocean wave energy resource(annual averages in kW/m width of wave)

3249

19

18

17

25

33

97

50

24

15

15

38

48102

92 70

38

19

21

5038

12

3414

40

43

7884

7248

37

10

20

18

41

Masuda buoy

Japanese wave-powerednavigation buoy, firstintroduced in 1960’s.Overall diameter 3m.Air turbine and 60W

generator, powered byoscillating water column.

Output stored inlead-acid batteries.

Flotation chamber

Oscillating air flow

Generator

NorwegianOWC schematic

Generator

Wells turbine

Circular splash guardwith annular spacefor air flow to turbine

OWC chamber

Norwegian OWC

500 kW prototypedevice on shoreline

near Stavanger.

Concrete OWCchamber toppedby steel tubular

tower. Single-rotorWells turbine.

Constructed in1985, destroyed by

storm in 1988

Prototype oscillating water column device, Portnahaven, Islay.Wells turbine and generator rated at 75 kW. Constructed

in 1985, de-commissioned in 1999

Islay prototype OWC schematic

OWC chamberWells turbine

Generator

500 kW rated, shoreline mounted oscillating water columndevice near Portnahaven, Islay

Aerial view of tapered channel wave power plant

Tapered channelSea

Reservoir

Turbine house (250 kW)

Wave Dragon

A Danish design: the arms amplify the incoming waveswhich spill over into a central chamber. Power take-off

uses simple low-head hydro power technology

An artist’simpression

of the device.

At full scale,it would be260 m wideand woulddevelop up to 4 MW

A 1/4.5 scale prototype Wave Dragon during sea trialsoff the Danish coast, 2003

Cockerell raft wave energy converterFunded under UK wave energy programme in the 1980s

Segmentedraft flexes

under waveaction. Powertake-off usinghigh-pressure

hydraulics.

1/10-scaleprototype

tested in theEnglishchannel

Salter’s DuckFunded under UK wave energy programme in the 1980s.

Schematic view of cross-sectionAngular motion between duck and spine actuates

hydraulic pumps for power take-off

Testing of ducks at about 1/10 scale in Loch Ness, late 1980s.Each duck is free to take up its own angular position relative

to the common spine

1/7 scale Pelamisin sea trials in the

Firth of Forth nearEdinburgh, 2001

Pelamis power conversion module

Hydraulic ram

High pressureaccumulator

Hydraulic motorand generator

Fluid reservoir

Hinged joint

Pelamis 750 kW prototype in transit to Orkney test centre