Next wave of the future

In theory, wave technology that captures power from the oceans has significant potential. It has been said it could possibly one day power the world without causing pollution. However, despite being under serious development for well over 10 years with millions of R&D dollars spent so far across the globe, it might be up to another 10 years before it is in widespread use as a commercially viable alternative to other renewables such as wind.

So what has been the challenge for the development of wave technology and what’s on the horizon for the future? Sustainability Matters talks to Edoardo Sommacal, Project Manager, Carnegie Wave Energy (CWE), to find out more about his company’s latest project and developments for the future of wave technology.

Named after a Greek sea goddess, the CETO technology developed by CWE harnesses the enormous renewable energy present in our ocean’s waves and converts it into zero-emission electricity and zero-emission desalinated water. Using a system of buoys that are fully submerged and permanently anchored to the sea floor, the current version CETO 5 has a rated capacity of approximately 240 kW per buoy.

“We believe there is a huge potential for capturing the energy in the oceans,” says Sommacal. “It can provide a continual source of energy and is not as seasonal as other renewable energy such as solar and wind. Our technology also has the added advantage that it has no visual pollution as the buoys sit under the water surface.”

Sommacal agrees that wave technology still requires some development but believes that in 10 years or maybe sooner, CWE’s new wave power technology (CETO 6), which has a target power capacity of 1 MW per buoy, has the potential to be a widespread competitive source of energy.

“In the past, the challenge with offshore wave technology has been finding a size of project that is cost effective and competitive in terms of power with other technology.

“Because the nature of offshore developments is expensive, our focus has been trying to minimise the offshore activities, such as the number of divers and construction of pipelines, in order to keep the cost down.”

So far, CWE and its partners have spent $100 million on the development of the CETO technology. In its most successful achievements to date, the first commercial demonstration of the technology is set to commence. CWE will be using three CETO 5 buoyant actuators to supply power and water to the Australian Department of Defence for use at HMAS Stirling, Australia’s largest naval base, located on Garden Island in Western Australia.

“This project came on the back of a 12-month feasibility study,” says Sommacal. “Garden Island, WA, was selected as an ideal spot to do the commercial demonstration as it is a safe location with waves not as big as further offshore sites.”

Unlike other wave energy devices, the CETO system will operate underwater close to the surface, where there is high kinetic energy in the waves and the CETO units are invisible from the shore. Attached to seabed pump units, the buoys move with the motion of the passing waves and drive the pumps. The pumps pressurise fluid which is then used to drive hydro-turbines, generating zero-emission electricity; as well as being fed into a reverse osmosis desalination plant.

“Desalination consumes a lot of power,” says Sommacal. “Therefore, the aim of the Garden Island demonstration project is to show how CETO can fit well with off-the-shelf desalination technology to reduce the power consumption with zero greenhouse gas emissions.

“The desalination system has already been pre-commissioned but is not yet using the wave hydraulic energy. We are waiting till the end of winter for the deployment of the first CETO buoy and to run the system through the hydraulic circuit. Additionally, once all the water quality approvals have been received, the water will be delivered to Department of Defence potable water infrastructure on Garden Island.”

The buoys float and are deployed by towing them offshore. Divers are then used to secure them to the seabed. Sommacal says the CETO 6 unit will be easier to deploy and will require fewer divers, saving time and costs on installation.

Timely access to capital can be one of the biggest challenges for technology development companies. However, Carnegie Wave Energy has recently received a large amount of investment to pursue its latest version of the technology - the CETO 6. Its $6 million capital raising measure in April was oversubscribed and reportedly generated more than $9 million through shares and private placements.

A further $11 million in funding will be provided by the Australian Renewable Energy Agency’s (ARENA) Emerging Renewables Program. In addition, the company is receiving a five-year, $20 million loan facility from the Clean Energy Finance Corporation.

The CETO 6 technology will have an increased generation capacity as the buoys are larger and can be placed further offshore in deeper water. Each unit has a target power capacity of 1 MW, four times that of the current CETO 5 generation.

“Currently, the CETO 5 requires a pipeline to deliver energy to shore,” says Sommacal. “The downside of this is you have to be closer to the shore because the pipeline CAPEX is high.

“CETO 6 will have all the hydraulic and power generation system inside the buoy so it can be deployed further offshore where more energy can be captured. It will also use oil and gas-style cable connection and avoid deploying pipeline. By using technology that is already available, the costs are minimised further.

“Also, the efficiency of the wave energy can be improved by ‘tuning’ the buoy to the prevailing swell conditions at any time. Additionally, an array of buoys can be installed on-site to accommodate prevailing swell direction, similar to how the turbines are oriented on a wind farm.”

Sommacal admits that the buoys are large and the new version will be even bigger, but they will be hidden under the water. “Wherever a buoy is installed, navigation will be limited,” he says. “But it will be simply marked on the map, straightforward, the same as mooring limitations for pipelines.”

Being able to supply both power and water with no emissions and no visual pollution makes this wave technology particularly suited to remote island locations.

The technology has potential and is certainly receiving a significant amount of interest from investors. It would be great if the spotlight remained on WA for the next wave of success - a commercial-scale wave technology.