Australasian Science Magazine

By Stephen Luntz

Modest-sized solar thermal plants could save almost $1 billion in investment that is otherwise required to upgrade electricity transmission to regional towns, with major reductions in carbon emissions a bonus.

Concentrated Solar Thermal (CST) power, where mirrors focus heat to boil a material, is substantially more expensive than photovoltaic (PV) panels or wind turbines but it has the advantage of offering relatively cheap storage. Of the 3 GW installed worldwide, the majority comes with storage, sometimes enough to run on full power through the night.

CST has much greater economies of scale than PV, so the trend internationally is towards larger systems. However, a new study suggests that 10–50 MW systems could prove more economically viable in Australia if sited appropriately.

Ms Jay Rutovitz of the University of Technology, Sydney’s Institute of Sustainable Futures says that Australia’s rising electricity costs are mostly driven by the poles and wires needed for transmission rather than on production costs or carbon pricing.

“We looked at case studies in Queensland where if a single element in the system failed there would be loss of supply to a town,” Rutovitz says. The cost of duplicating the transmission lines to avoid such risks would be very high, while transmission lines incapable of handling an increase in electricity demand link the South Australian riverland town of Monash to the grid.

Rutovitz found that CST would be cost-effective for Monash, Charleville, St George and Gunnedah. The systems would not supply the towns with 100% of their needs, but would remove the need for new transmission lines and keep essential services running if external lines failed.

“This study shows CST could be a viable alternative to traditional network augmentation in more than 70% of the cases examined,” Rutovitz says. “It also identified how $0.8 billion could be saved from network investment and how 533 MW of cost-effective CST power could alleviate constrained grid locations in the next 10 years.”

An additional benefit, Rutovitz believes, is that the construction of such systems would give Australia experience in building a technology with a big future. “Much of the research expertise is here, but it is going overseas to be commercialised. We missed the boat with PV, and it would be a shame if we missed out on being the owners of CST technology with the chances to sell to other countries.”