"How The Power Of Ocean Waves Could Yield Freshwater With Zero Carbon Emissions"
A new project in Australia aims to create freshwater by harnessing the kinetic force of ocean waves, RenewEconomy reports. Run by the Perth-based firm Carnegie Wave Energy in cooperation with the Water Corporation, and supported by a $1.27 million grant from the Australian Federal Government’s AusIndustry Clean Technology Innovation Program, the plant will use Carnegie’s proprietary CETO wave energy technology to power reverse osmosis desalination. The resulting process, free of carbon emissions, “will be a world first” according to CEO Michael Ottaviano.
Reverse osmosis desalination has been in use for several decades, and works simply enough: high pressure is used to force saltwater through a membrane, producing drinkable freshwater on the other end. Traditionally the pressure is provided with electric pumps powered by fossil fuels, resulting in both carbon dioxide emissions and lots of points for energy loss.
But instead of relying on those electric pumps, Carnegie is using the latest iteration of its CETO technology — CETO 5 — to supply that pressure with wave energy instead. Underwater buoys eleven meters in diameter are installed offshore, and as ocean waves catch them, the movement supplies hydraulic power to pump seawater up underground pipes to shore. At that point, the water runs into the desalination plant, where it directly supplies the pressure for the reverse osmosis. Some of that hydraulic energy is also converted into electric power as needed.
CREDIT: Carnegie Wave Energy
The resulting system not only cuts out all carbon dioxide emissions, it also greatly reduces the points where energy can be lost, making the process much more energy efficient and cost-effective.
The two megawatt demonstration project will be situated on Garden Island, near the coastal city of Perth in Western Australia, and will ultimately supply roughly 55 billion litres of drinking water per year. A previous desalination plant set up by Water Corporation in Kwinana, south of Perth, already supplies 45 billion litres. The final total of 100 billion litres a year is half the city’s drinking water needs.
Southwestern Australia has been especially hard hit by droughts, and unaffected by the reprieve from the dry period the rest of the continent has enjoyed. And climate change models project that the traditional freshwater supplies for Perth will dry up even further by 2030. Meanwhile, Australia as a whole has been suffering the ravages of climate change, what with record-setting heat waves, floods, and other extreme weather. So anything that could provide the country freshwater without adding anymore to the globe’s carbon emissions is a welcome development.