Some people claim that 50 per cent renewables by 2030 is ambitious, but it is entirely feasible and would not break the bank. It is also the minimum needed on the path to keeping emissions below the levels that would exceed the two degrees warming limit agreed to by the United Nations.

CSIRO modelling for our Deep Decarbonisation Pathways study show renewable energy shares of between 50 per cent and 70 per cent at 2030, on the way to a zero-carbon electricity system by mid-century. 

This would come mostly from a dramatic expansion of solar cells, both on rooftops and in large solar power stations, alongside an increase in wind power. Solar thermal power stations, including with storage, would also come into the system. Alternative trajectories include significant shares for nuclear power or carbon capture and storage, but renewables are the mainstay in all scenarios. 

This modelling takes into account the intermittent nature of renewable energy supply, and even assumes rising power demand on account of switching from direct use of oil and gas to electricity, to allow for very deep cuts in Australia's carbon emissions. Energy storage, new ways of managing energy demand and smarter power grids can make it happen. 

Our recent analysis shows doing cost-effective energy efficiency in buildings, industry and transport would keep Australia's emissions from growing. Switching to renewable energy in the electricity sector and using this low-emissions electricity to replace fossil fuels in cars, buildings and some industries would help reduce emissions to 25 per cent below 2005 levels. Carbon forestry and agricultural improvements can bring emissions down to about 45 per cent below 2005 levels. Switching to biofuels and gas, and reducing industrial non-energy emissions can bring Australia's emissions down to 50 per cent below 2005 levels by 2030. 

The economically sensible policy instrument to achieve all of these goals is to put a price on carbon. This could be in the form of an emissions trading scheme, or by turning the government's Direct Action policy into a baseline-and-credit scheme. Putting a price on carbon will also help with a renewables goal. Governments can also use direct regulation, which can work well for energy efficiency.  

Getting to a low-carbon economy will be about investment but also about innovation and managing the social transition that is inherent in any significant economic shift, and Australia has managed a few. It means being clear that building a resilient future means investing now, and building a societal consensus around this. Will Australia's politics be up to the challenge?