These 5 charts show how far rooftop solar and home batteries can take us – and why we still need the grid

These five charts illustrate the potential and limitations of rooftop solar and home batteries in powering Australian homes and cities. As of April 2025, nearly 26 gigawatts of small-scale solar capacity existed in the National Energy Market. On average, solar panels generated 4GW of power during January to March, equivalent to 16% of demand.

This is a significant increase from eight years ago, with rooftop solar capacity projected to nearly triple by 2050. At the commercial, industrial, and other building level, technical potential increases to around 179GW. However, even with all suitable household rooftops fully utilized, rooftop solar capacity would reach around 61GW.

Rooftop solar's output is inconsistent, with clouds reducing efficiency and no sunlight at night. As a result, solar panels produced 4GW on average from January to March, which covers 16% of demand. During periods of sunny weather and low demand, rooftop solar can meet around 60% of National Energy Market demand. The "duck curve," which represents low daytime demand and high evening demand, poses a challenge for grid operators.

Home batteries can reduce the amount of power households purchase from the grid during peak times, but their usable stored energy remains limited compared to rooftop solar generation.

While rooftop solar and home batteries have the potential to significantly reduce power demand from the grid, they are not a complete replacement for the grid, especially during evenings, heatwaves, or prolonged cloudy periods. Heavy industries, data centers, and large power users require continuous power supplies that cannot be fully met by small-scale production.

Home batteries, though beneficial, have limited stored energy relative to rooftop solar generation. New transmission lines, long-duration energy storage, and a few gas plants will be necessary to support the energy system alongside large-scale renewables and storage. The goal should be to create a resilient, integrated system rather than individual households disconnecting from the grid.