The academy's research used electricity generation cost data from the industry-backed Electric Power Research Institute in the US, adapted to an Australian setting. It was funded by the Australian Research Council but there is separate funding (across a Chinese Wall) to promote the paper, from Victoria's energy department, the Energy Supply Association, and the utility TRUenergy, a subsidiary of China Light and Power, which has its own nuclear reactors (including a minority-owned power plant near Hong Kong at Daya Bay in Guangdong province, which local media reported suffered an embarrassing radioactive leak in October, its third in six months).

Suffice to say, the academy paper is a decent piece of analysis in a contentious and uncertain field. The findings are now open to debate - critics say it is overly optimistic about nuclear (particularly a construction time of six years, the allowance for a 50- rather than 30-year payback, and the assumption that greenhouse gas emissions are zero), overly pessimistic about solar thermal (EPRI provides little evidence, but many predict solar thermal will halve in cost by 2020), and dubious in calculating present costs for non-existent technologies such as carbon capture and storage and hot dry rocks geothermal.

EPRI's starting point is not especially controversial. Coal and gas are the cheapest energy sources. Conventional geothermal from underground streams and wind are the cheapest renewables. Costs go up from there - through combinations of coal and gas with carbon capture and storage, nuclear, and (last) the various solar technologies.

The big question is, what's going to happen to the cost of these various technologies over the next 10 to 30 years? That requires a set of challengeable assumptions about learning rates and scale economies as new plant is deployed. Those assumptions are especially contentious with nuclear energy. Stepping back from the figures, it boils down to this: is the cost of nuclear going up or down?

Two papers released over the past fortnight come to exact opposite conclusions. Nuclear energy will be more expensive than most forms of renewable energy by 2020, according to a paper given at this week's solar industry conference in Canberra by Mark Diesendorf, the deputy director of the Institute of Environmental Studies at the University of NSW, which found that by 2020 offshore wind farms, solar thermal and solar photovoltaics (both residential and power stations) will all be less expensive than nuclear energy.