Going deep to harness wave power: Carnegie’s CETO systems

25 April 2016 (Last Updated June 10th, 2020 15:33)

Australia’s Carnegie Wave Energy has secured funding for its CETO wave energy projects and plans to build the first renewable micro-grid. The systems are unique as they operate underwater, which has many advantages, so could Carnegie be a major player in the future of wave energy?

Going deep to harness wave power: Carnegie’s CETO systems

CETO 6 Carnegie

Wave energy has the potential to supply around a third of Australia's energy needs, so it is no surprise that energy companies are making innovative advancements in this area. Western Australia-based Carnegie Wave Energy is one of the companies working on projects, and recently announced a new round of financing to take it to the next level.

In previous wave power systems, the challenge has been to design a machine that can withstand the brutal power of the ocean, and to find a gap in the market in the face of plummeting costs of solar energy and other renewables. Carnegie may have found the answer with its CETO wave energy projects.

Named after the Greek sea goddess, CETO offers the potential to revolutionise power and water production globally, according to Carnegie's website.

"CETO harnesses the enormous renewable energy present in our ocean's waves and converts it into two of the most valuable commodities underpinning the sustainable growth of the planet: zero-emission electricity and zero-emission desalinated water," Carnegie states.

Starting out with confidence

CETO systems work by converting ocean wave energy into electricity and desalinated water. It operates underwater with a fully submerged buoy that drives pumps and a generator, which looks like a metal balloon on a string tied to the sea floor.

The first use of Carnegie's current-generation CETO 5 wave project was in 2014 when it was successfully installed operating at the company's Perth Wave Energy Project site off Garden Island in Western Australia. It was called the Perth project, and everything ran smoothly during the trial, with the machine surviving waters of 5.8m deep and waves of over 3m, giving the developers confidence in their design's resilience and reliability.

All three CETO 5 units installed were in operation for 13,000 cumulative hours, and demonstrated the long-term survivability of the system as a larger-capacity CETO unit than any previously developed.

"Zero-emission electricity and zero-emission desalinated water."

The company said the successful operation of CETO 5 marked the completion of a critical phase in Carnegie's journey as a culmination of three years of hard work, design, financing, development and construction.

Now, Carnegie is working on a new A$46m project, CETO 6, which will be used in future commercial projects. A$11m of the funding comes from The Australian Renewable Energy Agency (ARENA), as well as a debt facility from the Clean Energy Finance Council (CEFC).

Each CETO 6 unit will have 1MW of power capacity, approximately four times the output of the CETO 5 systems, transmitting that power onshore via a subsea cable. Being submerged makes the design unique from other wave energy devices, as well as offering the machines greater protection from large storms and being invisible from the shore. The technology means power can be generated onshore or offshore, depending on the characteristics of the project.

A world first: the renewable micro-grid

While CETO 5 was the world's first multi-machine wave energy installation to deliver zero-emissions electricity, the idea now is to take that concept a step further by building the first renewable energy micro-grid based around wave energy.

The plans for this micro-grid, which is also based at Garden Island, combines wave energy with solar energy, a desalination plant and energy storage facilities. It will use three CETO 6 wave energy machines, each with 1MW of power capacity, 2MW of added solar and 500kW hours of battery storage. The unit will provide power and water for Australia's largest naval base, HMAS Stirling, off the coast of Garden Island.

The micro-grid can disconnect from the electricity network and operate autonomously, as the idea is for Garden Island to be completely independent for its electricity and clean water requirements.

Carnegie believes that this micro-grid concept can be applied anywhere, in island communities off Australia's coast and in other areas in the Pacific, Atlantic and Indian oceans. It could also be handy for coastal communities in remote areas of the world.

"This progress is a clear example that given time, and with the right government support, emerging renewable energy technologies can progress along the innovation chain towards commercialisation," said ARENA chief executive officer Ivor Frischknecht in February 2015.

Carnegie worked through a rigorous programme of onshore testing of the CETO units - 13,000 hours of demonstration - so that any problems could be identified before deploying them offshore.

"With the right support, renewable energy technologies can progress towards commercialisation."

As the units convert ocean wave energy into zero-emission electricity and desalinated water, it is an environmentally friendly option. The tests have proven that there are minimal environmental effects to marine life and there is no visual impact from the shore.

Future projects in the pipeline

It is likely that Carnegie will build its biggest wave energy project to date in the UK. The planned 10MW-15MW project will use CETO 6 technology, using the full-size 1MW machines and will occur in two stages.

Firstly, a single CETO 6 unit will be installed, and then nine or 14 further units, possibly reaching 15MW worth of power generation.

"The first unit is to demonstrate to the financiers of the second stage the unit performance at the same site," said Carnegie CEO Michael Ottaviano in an interview with Renew Economy in March earlier this year. "This is required to unlock more traditional project financing for the second stage. We would expect the first stage would be substantially EU grant-funded and we're aiming to have secured this grant later this year."

The company has projects in the pipeline for Ireland, Canada, Bermuda and Chile. Also, it is working on studies for wave-based micro-grids in Mauritius, and expects to take the technology to other remote areas and islands.

According to Ottaviano, Carnegie is the leading wave energy company in the world. With the company's thorough testing, flexible products, and environmentally friendly outlook, it is clear to see why it could be a big contender in the future of wave power.