Australia has passed through another significant solar milestone, reaching 3GW of solar PV this month, as Queensland nudged the 1GW mark and states such as South Australia reached household penetration rates of 25 per cent.

“Solar power is reshaping Australia’s electricity market,” says Warwick Johnston, the head of solar research group SunWiz, who compiled the data. “This is a milestone as note-worthy as the one millionth solar power system that was installed in April.”

The growth in solar PV in Australia is quite remarkable, given that Australia’s capacity was barely more than 180MW in 2009. Much of this growth came as a result of generous feed in tariffs, but the growth continues as a new generation of households look to solar to hedge against the rising cost of grid-based electricity, to make a statement about green energy, or to do both.

Australia is almost unique in the world in having its solar installations almost exclusively in rooftop solar PV. That, according to Johnston, now totals 3GW on its own, mostly residential but also on a growing number of commercial rooftops, such as wineries.

Australia has only one solar PV array above 1.2MW, the 10MW Greenough River solar farm in Western Australia, although three projects have begun or are about to begin construction in the ACT, and the 102MW Nyngan project will also begin construction in January. Others are in the wings. To put this into comparison, the Japanese market is expected to install 9GW of solar in 2013 alone, much of it at commercial or larger scale.

Some other striking figures in the latest data release from Sunwiz include the penetration rates in individual states.

Johnston says that nationwide, 14 per cent of dwellings host solar power systems; and one in four dwellings in South Australia have rooftop solar. Queensland has a penetration rate of 22 per cent, and WA 18 per cent.

This is having an impact on Australian electricity markets. Here’s another interesting statistic: At midday on Sunday, September 29, solar power contributed to 9.4 per cent of electricity demand in the National Electricity Market, and 28 per cent in the state of South Australia.

“Over the winter months, solar power contributed to 1.4% of total power consumption in the National Electricity Market, reaching a daily peak of 2.75% of energy NEM-wide production on September’s “Solar Sunday”, Johnston says. (See the graph below).

The solar market is having an impact on incumbent fossil fuel generators, and network operators. That’s because solar reduces demand from the grid, and also takes away revenues on what has traditionally been the most profitable part of the day for generators.

Queensland state-owned generator Stanwell Corp blamed solar for most of its woes, the decline of base-load generation and its inability to return a profit from generation last financial year. As Hugh Saddler remarks in another story today, some of its generators are operating at less than 50 per cent capacity. Many industry experts suggest solar is having such an impact on electricity markets that it is causing a near equal amount of fossil fuel generation to be mothballed or closed.

The Sunwiz report says that the solar market has contracted from its giddy, FiT-inspired peaks in the middle of 2012, but it is now stable. However, profitability for industry players remains a challenge, although the customer is benefiting. The months of October and November both recorded around 75MW of installations.

The average rooftop system has jumped to 4.3kW, the most popular size is now between 3kW and 5kW (depending on the state and its solar resources) up from 1.5kW, and 5 per cent of systems are more than 8kW (the average in the US).

South Australia boasted an average size of 4.8kW and that state overtook Queensland to be the largest market in Australia over the last two months. Localities such as Hilton, Lonsdale, Rosewater and Emu Flat set records for installations.

More information on the Sunwiz data can be found here.

