Australian wave energy pilot ends after two years at sea

Australian company Wave Swell Energy has retrieved its UniWave200 wave energy device after being deployed for over two years off the coast of King Island in Tasmania.

In late March 2023, the 1,000-tonne wave energy machine was successfully refloated from the seabed at Grassy Harbour in the Bass Strait, where it was fist installed at the beginning of 2021.

The Perth-based marine services provider Engage Marine assisted Wave Swell Energy with the retrieval and the tow of 200kW unit to the shore using its Engage Rival vessel, after which the decommissioning operation began.

“Outstanding support, customer focus and operational execution from Engage Marine and the team aboard Engage Rival. An important achievement proving the mobility of Wave Swell’s ocean-based power generation tech. Thank you,” said Paul Geason, of CEO Wave Swell Energy.

The UniWave200 device was installed approximately 100 meters from shore, in 5.75 meters of water depth.

The device started exporting power into the King Island’s grid in June 2021, operated by Hydro Tasmania, the island’s energy and network provider.

The power generation was then gradually scaled up, with the electricity being exported intermittently in relatively small sea states while the onboard systems were physically monitored.

The unit then began to be operated remotely, with some manual operation required while the control systems continued to be optimized.

Wave Swell Energy’s technology is based on the well-established concept of the oscillating water column (OWC). The UniWave200 device is partially submerged as it sits on the seabed, with an opening on one side to allow the movement of the waves in and out of the chamber.

The design of the UniWave200 has been modified from a bi-directional turbine which rotates in two directions, to a unidirectional turbine which rotates in one direction only, which is expected to result in a simpler and more robust design with high energy conversion efficiency and lower costs.

There are no moving parts below the water which means maintenance is only ever required to be performed on the easy-to-access areas of the device.

Wave Swell Energy commissioned Marine Solutions Tasmania, one of the leading environmental services companies, to complete a marine environment impact assessment at Grassy Harbour in December 2022.

The assessment concluded that the two-year long deployment and operation of the UniWave200 wave-energy converter had no noticeable effect on the ocean, seafloor and ecology of immediately surrounding areas.

The survey identified the marine species colonizing on the structure were representative of the surrounding reef community and any ongoing deployment of the unit would create an extended habitat for local marine species.

Geason said: “Whilst proving the capabilities of the WSE technology was the primary objective of the trial at Grassy Harbour, we take our responsibility to the environment seriously and we want to be assured the unit at Grassy Harbour, and future deployments, do not cause harm to the marine environment in which they are located.”

The assessment included mapping of the seabed, water-quality profiling and ecological field surveys at the location of the UniWave200 unit and in nearby surrounding locations.

In a positive outcome, the report provided by Marine Solutions concluded with respect to all parameters tested in the survey, there did not appear to have been any noticeable effects on the environment in which the UniWave200 unit was located and operated.

The pilot demonstration of the UniWave200 device at Grassy Harbour has been a success, fulfilling Wave Swell Energy’s objective to design a simpler, cheaper and robust wave-energy converter, according to the company.

“As we transition to scaling up deployments, this report provides data and analysis to include in future proposals addressing potential concerns for environmental impacts. A key reason for our technology having no noticeable effect on the marine environment is simplicity in design. The unit has no moving parts below the waterline which enhances the reliability of our technology.

“Establishing our technology has a benign effect on the marine environment further supports our ambition to ensure Wave Swell Energy’s technology delivers utility-scale clean electricity to mainland grids around the world and becomes a core part of the mix of renewables required to achieve net zero emissions,” Geason concluded.

Despite the demonstration being deemed a success, Geason said for ABC News that the technology is unlikely to experience significant uptake in the Australian market, due to the lack of appropriate policy and funding measures, and that Wave Swell Energy is looking into overseas markets, like the European, which has more progressive policies and funding options for emerging technologies.

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