We cannot create or destroy energy. It is only transferred from one form into another, and humans merely harness it where we can.
This law, the conservation of energy, underpins our physical world. Solar energy hits our oceans, turns into heat and creates water vapour, driving storms that whip up winds and waves – and it’s these natural energy currents that burgeoning renewable energy technologies are tapping into.
Most recently renewables have been tangled up in the aftermath of the superstorm that hit South Australia last week. While politicians squabble about the state-wide blackout, numerous renewable energy projects are whirring away uninterrupted across the country – producing clean energy and freshwater in unlikely places.
Under the sea
Off the coast of Fremantle, Western Australia, in an ocean usually known for its sharks, the Carnegie Wave Project is capturing the energy of the sea. An array of buoys sits fully submerged beneath the surface, each tethered to the ocean floor and invisible from the land.
The buoys rise and fall with passing waves, pumping high-pressure water ashore. This drives a series of hydroelectric turbines round-the-clock to generate electricity and simultaneously desalinate water.
This patented CETO technology has been connected to the grid since late 2014 and feeds Australia’s largest naval base, HMAS Stirling, on Garden Island with zero-emission electricity and fresh water.
Backed by the Australian Renewable Energy Agency, the array has already clocked up 14,000 cumulative operating hours but is set to expand further. The next generation of buoys, CETO6, will be installed together with on-land solar energy capture and battery storage to create a micro-grid designed for island settlements.
In sunburnt country
Meanwhile, outside of Port Augusta, South Australia, Sundrop Farms is transforming otherwise infertile land into a thriving agricultural greenhouse. There’s plenty of sunlight in the desert, but no fresh water. Sundrop desalinates saltwater from the nearby Spencer Gulf to irrigate their crops using concentrated solar-thermal power.
The assembly of mirrors is stunning: 23,000 panels (just regular bathroom mirrors) looking skyward to focus the sun’s rays onto a central tower, 127-metres tall. The intense solar energy is channelled into the water supply, producing steam. Steam turbines generate electricity and the heat powers the desalination process; excess electricity and heat can be stored on site. The energy is also used to regulate the temperature of the hydroponic greenhouses.
Sundrop’s farm in Port Augusta is officially opening today (6 October), but while running in test mode, it has already been supplying two truckloads of truss tomatoes daily to supermarkets. And the 20-hectare facility continued operating through the recent SA power blackout.
Not the future of renewables
However, renewable energy experts such as Professor Andrew Blakers from ANU will tell you that by far the most important renewables to focus on are the big ones - wind farm technologies and photovoltaic solar cells. “Ocean and thermal are tiny pimples in the graph,” he remarks.
Still, even if these two projects won’t transform the world as we know it, a strategically designed sustainable project built for a specific location can serve as inspiration for what humans can achieve when we look beyond traditional means of energy production.