Anthony Doesburg: Nuclear power likely casualty in tide of change

By Anthony Doesburg

Tsunami has swamped one energy trend but the sea is ushering in another.

Nuclear energy is seen as a lost cause for the next few decades. Photo / APN
Nuclear energy is seen as a lost cause for the next few decades. Photo / APN

Nuclear power can be all but written off in the wake of Japan's reactor emergency, believes the director of energy studies at Otago University.

"I would have thought that Japan will pretty much spell the end of the nuclear industry," says Bob Lloyd, an associate physics professor whose research speciality is renewable energy.

American radiation screening of airline passengers from Japan, and German moves to shut down old nuclear plants are helping to stoke anti-nuclear hysteria, Lloyd says.

"Even China, which is absolutely desperate for energy, is shutting down its plans and having a rethink. So I'm afraid nuclear is going to be pretty much a lost cause for the next 20 or 30 years."

Lloyd holds out little hope for development of new nuclear generation methods, the proponents of which believe they solve some of the intractable problems of today's fission reactors. Chief among fission's shortcomings is the risk of a reactor core meltdown and release of large amounts of highly toxic radiation, and the disposal of radioactive waste.

Fusion reactors - mimicking, for instance, the Sun's conversion of hydrogen to the lighter element helium, with the the release of limitless energy - remain a pipe dream. Some researchers are pinning their hopes on hybrid fusion reactors instead.

Graham O'Connor, a former scientist on the ITER project, an international effort to build a commercial fusion reactor, and Julian Hunt, a former fusion researcher, wrote last year in New Scientist that a hybrid reactor, combining fission and fusion, has several advantages over fission alone.

Hybrid fusion "minimises the environmental impact, reduces risks, enlarges reserves of nuclear fuel and is more flexible to operate". The fission reaction of a hybrid plant could burn nuclear waste produced in conventional fission reactors, changing it into material that decays in hundreds - rather than tens of thousands - of years. What's more, the pair wrote, hybrid reactors could produce variable power output, so would work well with renewable generation sources, whose output is unpredictable.

"Workable hybrid technology is still some way off, but given the inherent problems with fission and the uncertainty over fusion it has to be worth pursuing," they wrote.

Lloyd is unconvinced, saying more sophisticated technology tends to be orders of magnitude more complex and, as the Japan emergency demonstrates, today's difficulties are hard enough to solve.

No New Zealand Government of recent times has entertained the nuclear option. But in the 1960s a National Government considered building a nuclear power plant on the Kaipara Harbour.

Last week the National Government approved a quite different power scheme for the Kaipara, giving Crest Energy the go-ahead for the first three of up to 200 tidal flow turbines.

It's the breakthrough they've been waiting for, says Crest director Anthony Hopkins, who has been steering the project through the resource consent process for the past five years. If all 200 turbines are installed - a condition of the consent is that the plug can be pulled if harmful environmental effects are observed - the scheme will produce 200MW of power, enough for about 250,000 homes.

Tidal flow power generation has nothing like the complexity of nuclear. However, it is largely untested technology.

Crest will choose from two turbine types: one sort sits on the sea floor, and the other is buoyant and anchored to the bottom. Whichever Crest chooses, their scale is huge: the turbines will be more than 20m in diameter, with each revolution in the 9km/h current taking about six seconds.

But getting them in the water is still a couple of years away, Hopkins says. First, Crest has to raise some money: $600 million will be needed over 10 years.

How would they fare in a tsunami? Hopkins says that was a question they had to answer as they sought consent: they concluded large sand banks off the harbour mouth would be an effective barrier.

Lloyd backs renewable electricity generation but thinks a looming energy crunch worldwide counts against tidal schemes.

"In terms of tidal energy we're at about the same stage we were with wind energy 30 years ago, and wind energy has now evolved, it's there.

"Unfortunately 30 years gets us out to 2040 and by then the world will have half as much oil, we'll be at peak coal, we'll have even greater climate change problems, so the world economy is going to be pretty shaky. Given that, putting money into tidal energy is risky." Not as risky as nuclear, however, given Japan's experience.

Anthony Doesburg is an Auckland technology journalist.

- NZ Herald

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