Clean and green ... or nuclear?

"If nuclear power is the answer, it must have been a pretty stupid question." So says Prof. Ian Lowe, an academic at Griffith University and President of the Australian Conservation Foundation.

But others disagree. A recent article in the peer-reviewed journal Energy by Australians Martin Nicholson, Tom Biegler and Barry Brook (NBB), and summarised in On Line Opinion, asks which is the cheapest of the "fit for service", low carbon, baseload electricity sources. They find that nuclear is cheaper than gas or coal (both with carbon capture and storage), and that solar thermal power with energy storage is the most expensive option.

The findings are disputed. University of NSW academic Dr Mark Diesendorf argues that the cheapest renewable energy sources - including landfill gas, onshore wind, conventional geothermal and hydro - are already cost-competitive with nuclear power. Tom Burke, a senior adviser to Rio Tinto in the UK, states: "The brutal truth is that no one has yet managed to work out a way of getting nuclear reactors to burn uranium as effectively as they burn money."

But my main beef with the NBB paper is the way they frame the question. Of course it's important to consider the cost and immediate availability of low carbon, baseload electricity sources. And of course it isn't a "stupid" question. But even if we agreed with their conclusion that nuclear is the cheapest of those options, that's not the end of the debate.

The question that needs to be asked is this: what's the best mix of electricity supply sources for Australia in the context of growing scientific and public concern about climate change?

Energy efficiency and conservation (ignored by NBB) provide the first part of the answer - they can provide large, quick, cheap greenhouse emissions reductions. Numerous studies envisage energy efficiency and conservation doing much of the "heavy lifting" to reduce greenhouse emissions. For example a 2007 Australian Bureau of Agricultural and Resource Economics study estimated that energy efficiency would account for 55% of Australia's greenhouse emissions reductions, and 58% of global emissions reductions, by 2050.

We can curb the growth in electricity demand through energy efficiency and conservation, but we also need a major restructure of the electricity sector. Too much of the literature on "clean energy" options pays too little attention to the issues stressed by NBB - cost, and the need for reliable electricity supply.

Can we meet the NBB objectives, and can we do so without nuclear power? One relevant study was written by Hugh Saddler, Richard Denniss and Mark Diesendorf (SDD) in 2004. The SDD study maps out a restructure of the Australian electricity sector to the year 2040. It makes virtually no allowance for technical innovation, although there has been innovation in the six years since the report was written and there will be much more by the year 2040.

The SDD report also makes no allowance for cost reductions for renewable energy sources, either through innovation or mass production - the main practical consequence is that the role of solar electricity is limited in the SDD plan because of its cost.

Even with those constraints, SDD map out a credible plan which would reduce greenhouse emissions from the electricity sector by 78% by 2040 compared to 2001. The electricity supply plan comprises solar 5%, hydro 7%, coal and petroleum 10%, wind 20%, bioenergy 28%, and natural gas 30%.

What's not to like about the SDD plan? The main concerns are bioenergy and gas. In the SDD plan, a large majority of the bioenergy comes from crop wastes. This addresses one of the major global problems with bioenergy - competition for productive land, and flow-on effects such as increased food prices. There are other concerns with bioenergy that would need to be carefully considered, not least whether it delivers the claimed reductions in greenhouse emissions.

Gas, a finite resource, could replace coal fired plants for no more than a period of several decades. Emissions from gas fired plants are about half those from coal fired plants, but about 10 times greater than emissions from nuclear power and most renewables.