In Canberra, more than 20,000 households and businesses have solar panels installed, with one of the city's least wealthy areas, the postcode of 2615, leading the charge with 1502 systems installed. Queensland had the most installations of any state or territory.

Chief climate commissioner and report co-author Professor Tim Flannery said some of the biggest take-up was in mortgage-belt suburbs.

"It has astonished everyone. If you read the old energy white paper of 2009, it predicted we'd have about as much solar as we have today by 2030, so to get it that soon is pretty amazing,'' Professor Flannery said.

"The most significant factor has been the decline in cost. The manufacturing cost scale is so effective that you can now buy panels at a quarter of the price that you would have paid for them in 2002."

The report predicted solar PV would account for about 29 per cent of Australia's energy needs by 2050. Australia has the world's second-largest solar resource, with China's bigger landmass giving it the greatest potential. Despite this, Australia's 2400 megawatt hours per year of total installed solar capacity ranked only sixth in the world, well behind leader Germany's 32,200 MWh/year.