Australian
Monday 24/5/2010 Page: 26
THERE are so many prototypes being built or planned to capture wave energy that there seem to be as many shapes and sizes as you might find in a children's play box.
But there's one fundamental choice that distinguishes the offering: should it float on the water or be installed on the sea floor? Noone's done quite enough research and testing to discover which will be the most effective, and there seems good argument for both. One thing you don't want, however, is for your floating machine to sink to the bottom, or vice-versa.
The developers and financial backers of Oceanlinx's wave generation unit would have been mortified last week when its third-generation prototype, the Mk3PC, broke its moorings just off the industrial city of Port Kembla, and crashed into a nearby breakWater and sank, less than two months after the country's first grid-connected wave plant was officially launched.
The company is putting on a brave face, saying that enough data had been gleaned from the unit during its short period of operations, when it had performed at and even beyond expectations, for them to move ahead with a full-size model. It says the one-third-scale prototype, at 30m by 10m, and 170 tonnes, was only built to withstand 4m waves and this was easily exceeded last weekend. The full-scale model will be built to withstand 30m waves, the company says.
Oceanlinx is not the only wave energy developer to suffer such a misfortune. Finnevera lost its Aquaboy wave energy device in October 2007 because of a bilge pump failure. OPT, which has been chosen by the federal government to build Australia's first large-scale wave energy plant in Victoria, lost a device in 2002 it snapped when being towed into place.
Such mishaps can only be expected while new technologies are being developed, particularly in the harsh marine environment. Which is why Britain, in contrast to Australia, has gone for multiple projects, and its programs include Crown Estate's £4 billion ($6.9bn) investment to foster 10 different wave and tidal technologies and nursery sites at the marine energy centre in Scotland, and a new wave hub in Cornwall.
Two new-generation technologies have been unveiled in the past week, including a 230m-long, 1500-tonne "sea snake" developed by Pelamis Wave Power and energy firm E.ON. The extraordinary machine, which lies semi-submerged, is to be towed from London to Scotland next month. Just imagine 300 of those lying off the coast in a single array.
The other model was Aquamarine's "sea oyster," a 26m x 16m device that is attached to the ocean floor and has a large hinged flap that acts like a pump driven by ocean energy. Britain's fascination with offshore power can be partly explained by a report released last week that says the country has offshore energy resources, including wave, tidal, offshore wind and floating wind, equivalent to its North Sea oil and gas reserves.
The report, prepared by Boston Consulting and backed by the Offshore Valuation Group, a coalition of industrial and government organisations, paints three different scenarios: one where enough is developed to satisfy one half of Britain's energy needs; a second where it becomes a net electricity exporter via a European super grid; and the third where it becomes a net energy producer.
Wave and tidal energy sources would contribute a small but critical amount of this energy of up to 45GWs comparable to Australia's total current energy capacity with most coming from floating offshore wind turbines. "The UK is now most of the way through its first great offshore energy asset, our stock of hydrocarbon reserves," the report says. "The central finding of this report is that our second offshore asset, of renewable energy, could be just as valuable. Britain's extensive offshore experience could now unlock an energy flow that will never nun out."
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