Graph of the Day: Queenslanders continue rush to rooftop solar

Today’s graph of the day shows the number of rooftop solar systems in south-east Queensland, including the capital Brisbane and the Gold Coast, that are serviced by the Energex network.

The number of houses adding rooftop solar continues to surprise the network operators, with another 2,794 systems of 5kW or less added during the month of August. This was the lowest since early 2011, but it brought another 11.5MW of capacity into the system, despite the fact that participating households are being paid little for their exports.

The average size of the systems has also surprised network operators – 4.12kW, which is large considering the tariffs are designed to encourage self consumption. Perhaps the households are just using more electricity, or preparing for the addition of battery storage down the line.

There are now 66,737 systems on the retail-only feed-in tariff (green bar in graph), representing one-quarter of all small PV systems. The number of systems with the 44c/kWh tariff  (red bar in graph) has fallen as houses hosting those systems are sold.

Another interesting statistic is the growth in larger rooftop systems (5kW or more) during the month. In August, 107 large systems worth 1.47MW of capacity were connected to medium and large business and commercial customers in August, bringing the commercial systems total to 1,347 at 17.8MW of capacity.

The network operator believes this growth in large systems is fuelled by focused marketing, a desire to remain on energy-only tariffs (i.e. remain below the 100MWh pa threshold) and the maturing and more efficient connection processes under the ‘zero export’ option.

In total, Energex now has 267,656 rooftop solar PV systems connected and  871MW rated inverter capacity.  About half of this output is fed into the network, and half consumed at the point of generation.

One other item of note is the amount of sunshine in the south-east corner of the state in the middle of winter. This graph below shows that in June and July, the amount of solar exposure was well ahead of the previous year. Given the increase in solar capacity (around 150MW) over the last 12 months, it helps explain how solar played a key role in the low wholesale prices and negative pricing events experienced in July.