Typically 70% of energy in ocean waves is lost through bottom-friction as
the depth decreases from 100 m to 15 m. So the average wave-power per
unit length of coastline in shallow waters is reduced to about 12 kW/m.
The Oyster, developed by Queen’s University Belfast and Aquamarine
Power Ltd [www.aquamarinepower.com], is a bottom-mounted flap, about
12 m high, that is intended to be deployed in waters about 12 m deep,
in areas where the average incident wave power is greater than 15 kW/m.
Its peak power is 600 kW. A single device would produce about 270 kW in
wave heights greater than 3.5 m. It’s predicted that an Oyster would have
a bigger power per unit mass of hardware than a Pelamis.
Oysters could also be used to directly drive reverse-osmosis desalina-
tion facilities. “The peak freshwater output of an Oyster desalinator is
between 2000 and 6000 m3/day.” That production has a value, going by
the Jersey facility (which uses 8 kWh per m3), equivalent to 600–2000 kW