Rooftop solar installations have continued on their booming way in Australia, with more than 100MW of registrations in January 2018 delivering the best start to a year, nationally – ever.

According to the latest data from industry analysts SunWiz, a total of 111MW of PV was registered again in the first month of 2018, although part of this would include some carry-over from the end of 2017.

Capacity commissioned in 2017 currently stands at 1.207GW, according to the report, with this expected to rise to over 1.25GW after registration lag plays out.

The numbers for January, meanwhile, put the month an impressive 69 per cent ahead of the same time last year, and among the top five months ever, SunWiz says – despite installs being down on December 2017 numbers.

Growth has been particularly strong in the commercial solar sector, driven by a “fantastic performance” in the 75-100kW installation range, the report says.

The average system size of STC systems jumped to 7kW, according to the data, although this was largely because of an increase in volume in the 50-100kW range while the rest of the sizes contracted slightly.

On a state by state basis, Victoria started the year by registering “a significant amount more volume than in December,” while all states posted volumes above their Q3-2017 levels.

Victoria was the number one location for commercial PV in January, though 80 per cent of its registration was from 2017 installations, meaning its position is principally due to a greater lag between installation and registration than the other states.