Wave Swell plans wave device deployment off Tasmania

Wave Swell Energy plans to install a commercial scale wave energy plant in the Bass Strait, off King Island in Tasmania.

Wave Swell’s series of one-megawatt generators will cost up to $7 million to build, and at peak times will provide up to half the power for King Island’s 1,600 residents, according to the Australian Maritime College (AMC).

The Australian-based wave energy developer said it expects the cost of wave power to be less than 10 cents per kilowatt hour when built at scale.

The news follows the testing of Wave Swell’s device in AMC’s shallow water basin which demonstrated the technology was ready for commercialization, and found the performance of the device was at least 120% more efficient than a conventional device, according to AMC.

Tom Denniss, CEO of Wave Swell Energy, said: “The results indicate the technology is ready to assume its place as part of the world’s commercial energy generation mix, with a strong potential to be among the very lowest cost sources of power within a few years.”

Wave Swell Energy’s design is a concrete gravity structure that sits on the seabed at the water depth of 10 meters. It is based on the oscillating water column concept, which acts like an artificial blowhole with water rising and falling inside a chamber.

AMC said Wave Swell introduced novel vents that allow the air to escape from the chamber as a wave enters. The vents then close and as the wave passes, it draws air through the turbine.

This has two significant advantages, according to AMC, as the venting of the chamber when the wave enters reduces damping, meaning more water enters the chamber – resulting in an increase in efficiency.

This means that a simpler, more robust and efficient unidirectional turbine can be used, rather than a bi-directional turbine used by conventional wave energy converters of this type, AMC said.

Gregor Macfarlane, Associate Professor who led the research at AMC, said: “With advanced measurement techniques using laser diagnostics, we looked very closely at how water flows in and out of the chamber. This allowed us to modify the geometry of the device to make further significant improvements in efficiency.”

The AMC team also performed experiments in extreme weather conditions to measure the loads experienced by the concrete structure. The information has been used by the structural engineers to ensure the concrete device will withstand the conditions of the Southern Ocean over a 25-year period, AMC said.