Released today, this 200+ page report paints a relatively glowing picture of the oceanic-based energy regime, finding that wave energy alone could provide as much as 10% of Australia's energy needs; enough to provide for the greater Melbourne area.
According to Ian Cresswell, Director CSIRO Wealth from Oceans Flagship, "Given the potential of ocean energy and the fact that it's a very new technology, CSIRO wanted to understand what is the sustainable level at which this resource could be used for energy supply and whether it could be competitive with other energy technologies. Assessing the opportunities and challenges from resource to the market is a first for ocean renewable energy in Australia."
The report contains two key findings:
- Although wave energy could supply about 10 per cent of our energy by 2050, there are many economic, technological, environmental and societal challenges that will determine its place in Australia's future energy mix.
- The areas that could benefit from wave energy technology include Perth, the southern coastline and to a lesser extent the east coast of Australia. Tidal technology could supply niche areas such as north east Tasmania and the Kimberley region in Western Australia.
Of interest is that (perhaps not surprising) wave energy is most abundant in the south and west of Australia, while tidal energy is generally most prominent in the north, where large tidal ranges are common.
CSIRO image of wave energy data
However, the report (quite deliberately) highlights many of the negatives associated will all of these resources.
The primary problem is for tidal energy. More than any other, the harvesting of this source of energy directly affects the environment from which it is taken. The reason is that the 'best' tides occur in geographically constrained locations where damming the flow has a direct influence on the surrounding area, a river estuary for instance.
Additionally, wave energy relies on thousands of small energy collectors at the mercy of sea water and its corrosive effects. As discussed on ABC Radio's AM program this can be a major concern where CSIRO's Alex Wonhas observed, "The technical challenges are really around making sure these devices last in the quite hostile ocean environment for maybe one or two decades. The commercial challenge is about reducing the cost of these devices."
According to the CSIRO report, "The west coast of Tasmania is about 300km long and the waves are incident nearly normal to the coastline, so the total energy incident on the west coast over a year is about 134TWh, or 12.2 times Tasmania's present consumption (11TWh/yr) of electrical energy."
It continues, "Hemer and Griffin [a referenced paper] made a more accurate model-based calculation of the total amount of energy crossing the 25m isobath between Geraldton, WA and the southern tip of Tasmania. This came to 1329TWh/yr (without attempting to correct for the possibility that the model slightly over-estimates the energy flux), about five times the energy requirements of the whole nation. Turning just 10 per cent of that into electricity would be a massive investment but would provide half the country's electricity."
Tempered with that of course is the fact that covering the ocean with wave energy collection buoys such that 10% of the available energy was harvested would be a major impact on shipping (to say the least!).
The third of the ORE resources is ocean currents. These are generally available in deep water and well off-shore. Neither aspect making them particularly amenable to harvesting. To make matters worse, they have an extremely wide profile and would require huge infrastructure to harvest a resource significantly smaller than waves. Can anyone picture a forest of sub-sea "wind turbines?"
Co-author of the report Dr Sam Behrens will be presenting the findings during Clean Energy Week, on Thursday 26 July at the Sydney Convention and Exhibition Centre.