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Wave power device a swell innovation

News story

Despite Australia boasting a coastline of around 35,000 kilometres, wave power has typically placed a distant third to the country’s wind and solar developments, and is an expensive pursuit. One company looking to challenge this is Bombora Wave Power.

A breaking wave.

Based in Technology Park, Perth, Bombora has invented a revolutionary and environmentally friendly conversion system that transforms ocean waves into clean, renewable electricity. Named the mWave, the electricity it produces could be cost competitive with other renewable energy sources by the mid 2020s.

“Ten per cent of the world’s energy could be derived from waves,” says Executive Director of Bombora and Curtin engineering alumnus, Shawn Ryan. “There’s a huge opportunity to make a substantial difference to the world’s future.”

What lies beneath

In many respects, wave energy is a very attractive source of power in comparison to other renewables due to its density, abundance and predictability. Waves are immensely strong. In an average wave, where each cubic metre of water weighs about one tonne, a 10ft tall wave across a 20ft wave front weighs approximately 410 tonnes, the equivalent of around 315 small cars. That is a very large moving mass of water.

It is difficult and expensive to build structures in the ocean that can withstand such a force. But research has revealed that more than 80 per cent of wave energy is accessible 10 meters below the ocean’s surface, and it’s here that Bombora’s technology flourishes.

Bombora’s mWave captures wave pressure from the sea floor, enabling a simpler and more cost-effective design. It comprises a concrete structure that rests on the sea floor and features a series of air-inflated rubber membranes arranged at an angle to the incoming waves. As waves pass over the device, air inside the membranes is squeezed into a central duct and through a turbine, which spins a generator to produce electricity. The air is then recycled to reinflate the membranes, ready for the next wave.

Each full-scale Bombora mWave has the potential to supply sustainable electricity to 350 homes.

Falling costs

“The reason we can produce energy at very low cost is because we use very simple components; concrete, membranes and a turbine,” says CEO of Bombora, Sam Leighton.

“The mWave is able to survive winter storms because it is a very robust construction and is mounted on the sea floor away from destructive waves. Combining our excellent energy conversion efficiency with the low cost of each device enables Bombora to achieve a very low-cost power.”

“All the features and benefits of the device come back to cost of energy,” adds Ryan. “Our convertors are located close to the shore so we can have a shorter cable run. Our electronic plant is sitting on the shoreline; we can drive up to it with an electrician and a screwdriver, we don’t have to get on a boat that could cost thousands of dollars a day.”

Curtin University is the first institution to partner with Bombora, and the company has been able to optimise the mWave’s engineering and technology with input from the University’s research facilities and the Pawsey Supercomputing Centre.

Market expectations

The mWave’s optimised design, combined with low installation and maintenance costs, means Bombora can deliver a Levelised Cost of Electricity (LCOE) below current market expectations for the wave energy industry.

Wave energy Levelised Cost of Energy projection graph. Source: ARENA.

Wave energy LCOE (€/kWh) projection as industry deployment increases (blue curves) (SI Ocean, 2013) (MRIA, 2016). Bombora mWave LCOE results from this Study (orange arrow). Ireland wave energy feed in tariff (26c/kWh green line). Wave Energy Scotland LCOE target for wave energy (green dot). Borrssele offshore wind farm (10c/kWh yellow dot). Source: ARENA.

An independent review of a 2016 Bombora wave farm feasibility study found that the LCOE for a 60 megawatt (MW) wave farm had an estimated range of 25 to 49 cents per kilowatt per hour (kWh). By comparison, current projections for other wave farms of equivalent capacity estimate power costs between 46 and 86 cents per kWh.

As Bombora, and indeed all renewable companies, continue to develop their technology and deploy more devices, total costs of renewable energy will continue to decrease. This trend is already well underway for wind and solar energy costs.

According to the latest Bloomberg New Energy Finance report, globally, the LCOE from solar is now a quarter of its 2009 value and is predicted to decrease by another 66 per cent by 2040. The report also predicts the cost of on and offshore wind to continue to fall by 47 and 71 per cent respectively as competition increases and turbines become more efficient.

Politics and the planet

Such predictions are certainly welcome at a time when the nation’s energy strategy is facing uncertainty. At the time of writing, the Federal Government proposed to scrap the proposed Clean Energy Target recommended by Dr Alan Finkel in The Finkel Review (a 26-28 per cent cut to greenhouse emissions by 2030) and is now tabling two new targets put forward by economist Ross Garnaut.

Though Western Australia’s energy system has developed in isolation from the eastern states, a new report by the Bankwest Curtin Economics Centre shows that the state government also lacks a clear strategy when it comes to renewable energy.

The report, Power to the People, WA’s energy future, states that accessible, secure and affordable energy is a necessary component of any well-functioning economy, and the imperative to move to a greener source is a position that many citizens, communities and governments are taking. However, the report states that Western Australia is lagging behind on this front, and has no clear renewable energy plan or target, despite other states taking such steps.

Renewables progress

Gas remains the main source of energy in WA, accounting for more than 50 per cent of our net energy consumption in 2014-15. In comparison, 2.1 per cent of our energy consumption is sourced from renewables. But there are pockets of progress. Bombora’s device has generated keen national and global interest, and the company has recently launched a project to construct and install its first 1.5MW commercial-scale mWave.

Bird'seye view of Como Jetty with Bombora wave energy convertor.

Bombora installed its first wave energy convertor off Como Jetty in 2015. Photo credit: Bombora.

Bombora is also supportive of the recently announced $19.5million state-funded Wave Energy Centre of Excellence in Albany, which includes a wave energy demonstration project and the creation of a supporting research hub. The Centre will bring together Western Australian universities and industry to progress wave power technology, and aims to transform Albany into Australia’s first renewable energy city.

Looking ahead

Wave energy has many attractive features, however the commercialisaton of wave energy converters technology is not without its challenges. Clear renewable energy policies with supporting funding initiatives are necessary to create the business environment for continued investment and commercialisation activities in the wave energy technology sector.

With companies like Bombora leading the way in the renewable wave energy space, Western Australia’s energy future looks awash with possibilities.

“Renewables are going to be business as usual in the not too distant future,” says Ryan. “Coal and gas have already had their day in terms of an economic case. Solar and wind renewable energy have attracted a huge amount of support and they are now becoming fully cost-competitive. Wave power is the next key energy source in this transformation to renewable energy. I don’t see how we can go back from this new paradigm.”

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