Scientists explore the possible side-effects of large-scale solar farms. Photo: Fran.ATKINSON@theage.com.au
AUSTRALIA'S solar energy abundance is common knowledge. Now a CSIRO-led team wants to know if that power might one day be harnessed to make rain.
CSIRO climate scientist Alberto Troccoli said large clusters of wind turbines were known to have an effect on micro-climates. His team is among the first in the world to investigate whether vast arrays of solar photovoltaic panels in one location might have a modifying — and controllable — impact on rainfall patterns.
If it looks like it works, it's going to be the biggest project Australia's seen
John Riedl, chief executive of a private equity group Game Changer Ventures providing the bulk of the study's funding, said the concept was simple enough but might take years to confirm its full potential.
"If you make a big solar array, you're effectively making a big refrigerator because you're absorbing energy that would otherwise hit the ground," Mr Riedl said. The resulting heat differential, if large enough to reach up into the rain band, could trigger rainfall under the right conditions, he said.
The solar panels themselves could be constructed to amplify or reduce their impact. For instance, the panels' dark silicon surface could built with a reflective underside that would be flipped if operators seek to reverse the cooling effect.
"You can change how the wind flows over the surface [of the panels]," Dr Troccoli said.
Mr Riedl said the scale might need to be as large as 100 kilometres by 100 kilometres. Even though such magnitude might place any project in the realms of science fiction, he said the prospect of creating extra rain to turn fringe farmland into productive tracts - not to mention the electricity boon - was enticement enough to explore its potential.
"If it looks like it works, it's going to be the biggest project Australia's seen — far beyond the Snowy River Scheme."
Dr Troccoli is more circumspect. "It's really early days. It's too early to tell one way or the other," he says.
Still, Queensland, with its access to more moisture-laden weather flows, might be more suited to such solar-rain farms than much of Western Australia, he said.
The study may be of interest to other parts of the world, including to backers of the proposed Desertec project to develop a giant 500-megawatt solar energy plant in Morocco to export power to Europe.
The study's first results, modelling the impact of solar arrays using existing meteorological data, will be announced at a conference of the Australian Meteorological and Oceanographic Society in February, Dr Troccoli said.
The findings may have a side result – confirming or negating community concerns that the construction large-scale solar may have deleterious effects on the local environment.
“It works both for the critics and for the supporters,” Dr Troccoli said. “It’s a question many people will ask.”