One in five homes in South Australia has rooftop solar. In Melbourne, adoption rates in western suburbs outstrips inner city by a factor of 5:1

Some interesting data on the penetration of rooftop solar PV in the southern states of Australia was included in the interim results of one of the major private network operators, Spark Infrastructure.

According to Spark, the main electricity distributor in the state, the level of residential solar penetration in South Australia has grown to 19.2 per cent as at June 30, confirming anecdotal estimates that one in five houses in the state now have rooftop solar in the state.

The level of penetration rose from 17.2 per cent a year earlier, and helped contribute to another 4 per cent fall in electricity volumes from residential customers, along with a 9 per cent fall in hot water. Spark has 835,000 customers in South Australia, most of them residential.

The story in Victoria was quite different. Spark owns two distribution networks in that state, one based on the western suburbs of Melbourne (Powercor) and the central and western regional districts, and another on the inner suburbs of Melbourne and the CBD (CitiPower).

The penetration of rooftop solar in PowerCor’s area (it has 774,000 customers and accounts for more than one quarter of the state’s electricity users rose to 10.4 per cent of homes from 8.0 per cent a year earlier, while in CitiPower’s area, the penetration in the inner city rose to just 2.3 per cent from 1.8 per cent.

Powercor’s electricity volumes from homes were down 3.3 per cent over the year, while CitiPower’s were relatively muted because of the low penetration, but fell 0.8 per cent.

In all three areas, the consumption of electricity by small and large business increased, offsetting the decline in residential consumption.

Despite the fall in consumption and the impact of solar PV, Spark’s revenues are protected because the bulk of them are regulated under setting from the Australian Energy Regulator.

The latest five year period, which has shown consistent over-estimates of consumption, will conclude in 2015. From then on, it could get more interesting for the network operator.