Rooftop solar at 23% of homes in South Australia – is storage next?

The surge in rooftop solar continues unabated in South Australia, with the local grid operator reporting that another 17,000 homes installed rooftop solar in 2014, a rise of 11 per cent over the previous year – and 23 per cent of all residential customers now produce their own solar energy.

The latest update was included in the annual results of Spark Infrastructure, which owns SA Power Networks, as well as two network operators in Victoria.

South Australia is the star performer, thanks to excellent solar resources and historically high retail prices. It is estimated there is now more than 550MW of rooftop solar on 174,000 installations in the state.

Interestingly, SA Power Networks seems to indicate that solar is helpful to the network. “PV is shifting (the) peak, but also helping reduce stress on the network during heat-waves,” it said in its presentation, echoing comments of previous years. Indeed, the peak is now at 7pm to 7.30pm in the evening, when it would have been late afternoon previously.

This means that the volatility on the electricity markets has been greatly reduced, much to the chagrin of the fossil fuel generators who used to profit from those regular surges in demand.

However, SA Power Networks indicated it would be moving to change its network charges to “demand” based, rather than consumption based. This would address the overall fall in demand caused by the big uptake in rooftop solar.

But executives also admitted it could encourage home-owners to install battery storage. The timing of that, said Sean Kelly, was still unclear. But he said that could provide a further benefit for the stabilisation of the network.

It is a different story in Victoria, however. Powercorp, which services the western suburbs of Melbourne and the central and western regional districts, has a penetration rate of 12.6 per cent, up from 11.1 per cent. But CitiPower, which is based around the inner suburbs of Melbourne and the CBD, has a solar penetration rate of just 2.8 per cent in residential homes, presumably because so many residential accounts are in apartment blocks.