Extracting twice the power from ocean waves

Senior Engineer Johannes Straub laying-up a glass fibre composite component for prototype development of wave energy converter project (image courtesy of ACS Australia). Composite mooring tensioner for wave energy converters (image courtesy of Carnegie Clean Energy).

aims to deliver efficiency advantages, significantly enhancing WEC technologies, and contributing towards the supply of lowcost energy to onshore grids, offshore platforms, and aquaculture operations. “We are inspired by the opportunity to work with Carnegie Clean Energy and the Blue Economy CRC project partners to develop advanced engineered composite mooring tensioners for Wave Energy Converters, enabling the evolution of renewable energy systems and reducing carbon emissions in aquaculture,” says Paul Falzon, General Manager at ACS Australia. ACS Australia’s talented team of engineers and technicians are continuously being challenged by a diverse range of projects where advanced composite materials are being applied. The team’s passion for advancing the technology of composites into sustainable renewable energy systems can be seen in their product development work with the Blue Economy CRC partners, among others. www.acs-aus.com

New clean energy tech extracts twice the power from ocean waves

Researchers have developed prototype technology that can double the power harvested from ocean waves, in an advance that could finally make wave energy a viable renewable alternative.

The power of coastal waves around the world has been estimated as equivalent to total global electricity production. With over 35,000km of coastline, Australia is ideally placed to tap into this power source. Analysis shows Australia could produce twice its current electricity output by harvesting just 17% of its wave energy. But the challenges of developing technologies to efficiently extract that power and withstand the harsh ocean environment have kept wave energy stuck at experimental stage. A research team led by RMIT University has created a wave energy converter that is twice as efficient at harvesting power as any similar technologies developed to date. The innovation relies on a worldfirst dual-turbine design. “While wind and solar dominate the renewable market, they are available only 20-30% of the time,” said lead researcher Professor Xu Wang. “Wave energy is available 90% of the time on average. Our prototype technology overcomes some of the key technical challenges that have been holding back the wave energy industry from large-scale deployment. With further development, we hope this technology could be the foundation for a thriving new renewable energy industry.” One of the most popular experimental approaches is to harvest wave energy through a buoy-type converter known as a “point absorber”. Ideal for offshore locations, this technology harvests energy from the rise and fall of waves, and is generally costeffective to manufacture and install. However, it must be precisely synchronised with incoming wave movement to efficiently harvest the energy. This usually involves an array of sensors, actuators and control processors, complicating the system and undermining performance and reliability. The RMIT-created prototype needs no special synching tech, as the device naturally floats up and down with the swell. “By always staying in sync with the movement of the waves, we can maximise the energy that’s harvested,” Wang said. “Combined with our unique counter-rotating dual turbine wheels, this prototype can double the output power harvested from ocean waves, compared with other experimental point absorber technologies.” The device has been developed by RMIT engineering researchers in collaboration with researchers from Beihang University in China. Two turbine wheels, stacked on top of each other and rotating in opposite directions, are connected to a generator. The generator is placed inside a buoy above the waterline to keep it out of corrosive seawater and extend the device’s lifespan. The prototype has been successfully tested at lab scale and the research team is keen to collaborate with industry partners to test a full-scale model, and work towards commercial viability. “We know it works in our labs, so the next steps are to scale this technology up and test it in a tank or in real-life ocean conditions,” Wang said. “Tapping into our wave energy resource could not only help us cut carbon emissions and create new green energy jobs, it also has great potential for addressing other environmental problems.” www.rmit.edu.au