Harnessing ocean power is no longer just a dream for New Zealand

WELLINGTON, NEW ZEALAND - This is a blue planet and it's getting bluer. Seventy percent of the Earth's surface is covered in water. The ice-caps are melting, shorelines are slowly receding, islands are going under.

Suddenly marine power - the new thing on the energy scene - looks mighty appealing.

It takes advantage of the immense (and free) power of the oceans and, because the process is so clean, it might also help stop the rising oceans drowning us all.

That's at least one reason the Government is now so interested. In the draft New Zealand Energy Strategy released recently, marine energy was hailed as "a developing technology of significant potential".

"New Zealand has a vast marine energy resource if it can be tapped," the report said. To back that up, Energy Minister David Cunliffe announced an $8 million contestable funding package for the industry.

Put simply, marine power is technologies to capture the motion of waves and tides, and turn it into electricity.

Already, the technological approaches come in all shapes and sizes. Last year, three 150m-long snake-shaped devices were planted off the northern coast of Portugal.

The long, red pontoons - the first of a planned wave farm for the area - stretch out across the ocean surface like lane markers in a swimming pool.

As waves hit them, they bend at specially designed hinges, transforming the motion into electricity using power-converter modules that run down their sides.

Other wave-power designs include buoy-like machines that catch the ocean swells, as well as structures built into coastal cliff faces that use air pressure from waves to power turbines.

Tidal power is the other half of marine energy and it's simpler to understand.

Typically, one long barrage, or a series of underwater turbines, uses the tide's energy as it moves in and out. It's this sort of project which has so far been most developed in New Zealand. Auckland firm Crest Energy plans to install turbines in Kaipara Harbour, which it says could eventually generate 200 megawatts - or enough power for 250,000 homes - at full capacity.

Plans are also afoot to develop something similar in Cook Strait, where Neptune Power director David Beach believes thousands of small turbines could sit 40m under the water.

The idea of using the ocean to generate electricity emerged in the 1970s when University of Edinburgh engineer Stephen Salter devised a prototype wave-power device known as the nodding duck.

However, with oil prices declining again in the 1980s, development money dried up.

The comeback is on now, though, with Britain leading the charge. A wave farm is close to being launched in Scottish waters, while plans to milk at least three of Britain's largest rivers for their power are under way.

Marine power prototypes have also been launched in seas or rivers off Western Australia, Japan, China and Spain. One British device, dubbed the Snapper, has shown the potential to be 10 times as efficient as existing models.

Governments have been taking notice. A report by Britain's Carbon Trust - set up by the government there to reduce greenhouse gas emissions - estimated last year that marine energy might eventually power 20% of Britain.

That's about 12,000 megawatts a day, or three times what the largest British power plant now produces.

Meanwhile, the World Energy Council has estimated the global export market for such technology could eventually be worth more than $1.5 trillion (New Zealand dollars).

In the United States, congressional committees have started taking submissions from marine energy players, while state- sponsored projects are sprouting along the seaboard, especially in California and the northeast.

Dr John Huckerby, one of the drivers of the local movement, and the head of Awatea - the Aotearoa Wave and Tidal Energy Association, welcomes the $8 million Government injection.

He says blue energy could contribute to our power supply by 2010, and eventually provide 20% of our power.

The Government's recent cash investment will encourage private capital, adding that with 14 local projects already in the pipeline, marine energy is perfect for New Zealand's creative approach to technology, he says.

There are hurdles to marine power. One barrier that the Economic Development Ministry and Dr Huckerby identify is the Resource Management Act.

"The Government needs to give consideration to whether the Act is the best mechanism for the allocation of space and resources for marine energy projects."

The next step, Dr Huckerby says, is for the Government to come up with incentive packages.

Feed-in tariffs are one option and are already being used in Europe, particularly for solar power, with electricity companies paying for electricity that is fed back into the public grid.

The other hurdle is cost. No matter what the incentive, it is clear that marine power will be expensive for the first few years.

The London Economist puts the average cost of British marine power at somewhere between two and five times the cost of power from natural gas.

Dr Huckerby says it's about twice as expensive as wind power at the moment, although many industry experts think they may even up in the future.

Another challenge for innovators is designing machines that are hardy enough to withstand what the sea can throw at them, without having to be prohibitively huge or expensive.

"To be frank, no devices have been put in the water for long enough to really test that yet," Dr Huckerby says.

Other issues critics have raised are similar to those levelled at the wind power industry - unsightly blots on the landscape (for those visible from land), lack of predictability, and damage to wildlife.

Where wind turbines have attracted charges of killing birds, The New York Times reported one case where a series of tidal turbines in the East River were scuttled after environmentalists complained of potential damage to fish.

However, environmental economist Ralph Chapman, an associate professor at Victoria University, says it's a smart move for New Zealand to develop new technologies.

"We've got to pick a few areas where we can develop an edge. There are really good examples of where governments have invested strategically in these areas - the Danish wind industry, for one. It's made a big difference there."

Wave power was a good option as New Zealand had a long coastline and big wave resources because of our latitude, he says.

"The British are really zooming ahead, so we would have to work with them."

If anything, $8 million may not be enough to keep up, Mr Chapman says.

But evidence of climate change grows by the week and it is clear governments like New Zealand's are keen to be seen as responsive to an issue of which the public is growing more aware.